Clinical Cancer Research Meeting Calendar Advances in Breast Cancer
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Meeting Abstracts Online
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Dowsett, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Dowsett, M.
Clinical Cancer Research Vol. 9, 502S-510s, January 2003
© 2003 American Association for Cancer Research

Supplement

Preoperative Models to Evaluate Endocrine Strategies for Breast Cancer1

Mitch Dowsett2

Academic Department of Biochemistry, Royal Marsden Hospital, London SW3 6JJ, United Kingdom


   ABSTRACT
Top
 ABSTRACT
Introduction
 Therapeutic Trials
 Incidental Trials
 Summary and Conclusions
 REFERENCES
 
There are essentially two approaches to presurgical therapy. The first strategy is one in which the therapy is given to downstage the disease over a period of some 3–4 months. In these circumstances, biological studies can be conducted that can be associated with clinical response. The second strategy involves the institution of medical therapy before surgery with no delay to that surgery. This is essentially incidental and is not given with the aim of having a therapeutic benefit but rather for the biological study of the particular therapeutic approach. In the incidental therapy scenario, we have conducted a number of studies to evaluate the biological effects of raloxifene, idoxifene, fulvestrant (in comparison with tamoxifen), and the aromatase inhibitor 4-hydroxyandrostenedione. Significant reductions in proliferation were noted in all, as was down-regulation of estrogen receptor levels. The changes were most profound in those estrogen receptor-positive tumors that were also progesterone receptor positive, consistent with the greater clinical effect of these therapies in this population. This setting is particularly valuable for treatments in which there is no particular evidence for clinical benefit but in which the therapy is known to be safe. It is possible to evaluate potential resistance mechanisms by associating changes in Ki67 or apoptosis with the expression of the putative determinant of resistance in the short-term presurgical model.


   Introduction
Top
 ABSTRACT
 Introduction
Therapeutic Trials
 Incidental Trials
 Summary and Conclusions
 REFERENCES
 
Over recent years, a series of studies has been conducted in which endocrine agents have been assessed in breast cancer before surgery. Largely on the basis of Fisher’s studies in rodents (1) , there has been consideration that preoperative medical treatment might have a beneficial effect on long-term outcome (disease-free or overall survival). The National Surgical Adjuvant Breast and Bowel Project B18 trial (2) established that for cytotoxic chemotherapy there were no significant differences in long-term outcome between adjuvant and neoadjuvant therapy, thus refuting survival benefit but importantly establishing the safety of the approach. It also demonstrated that achievement of a pathological complete remission in the primary tumor was significantly associated as an independent factor with improved survival, thus linking the behavior of the disease preoperatively to long-term benefit from treatment. However, there have been no randomized trials to establish whether these relationships hold for endocrine therapy.

There are two scenarios of preoperative treatment: (a) therapeutic trials in which surgery is delayed, normally for 3 or 4 months, to allow the treatment(s) to achieve a reduction in tumor size; and (b) incidental trials in which there is no substantive delay to surgery, treatment is given normally for 1–3 weeks after diagnosis, and efficacy is judged by changes in biological markers.

The two scenarios have different advantages and limitations, which are compared below, but both are highly attractive for the rapid evaluation of strategies in early-stage breast cancer. Such evaluation would take upwards of 10 times as many patients and follow-up for a number of years rather than weeks to months if conducted as postsurgical adjuvant therapy. A substantial advantage in making comparisons of drugs in the preoperative setting is that the heterogeneity of the disease can be established for known prognostic and predictive factors to avoid the uncertainty that can occur in studies in metastatic disease. In both circumstances, however, it is important to consider that the benefit of the agents seen in the preoperative setting may vary from that in the adjuvant setting and in metastatic disease.

Possibly the most valuable aspect of the preoperative setting is the possibility of studying the biological characteristics of responsive and resistant tumors and the biological changes that accompany response and resistance (and therefore may be useful as surrogate markers of response). In most cases, this involves the collection of tissue samples (Fig. 1)Citation , but it may also involve the application of imaging techniques such as nuclear magnetic imaging/spectroscopy or positron emission tomography (3 , 4) .



View larger version (29K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 1. Diagrammatic representation of the two preoperative settings (therapeutic and incidental) and the samples available. The filled circles represent the breast tumor. R, responder; NR, nonresponder. 3w, 3 weeks; 3m, 3 months presurgical therapy.

 
In addition, presurgical studies provide an opportunity for parallel metabolic studies of the treatment(s) in the absence of the confounding impact that metastases and concurrent treatment have in advanced disease. For example, in advanced disease, studies of the metabolic effects of treatment on bone biomarkers are impossible to distinguish from the resorptive effect of bone metastases, even if these are not clinically obvious, and the impact that treatment may have on any resorption. Such studies may be readily undertaken in preoperative studies without the risk of such confounding factors (5) .


   Therapeutic Trials
Top
 ABSTRACT
 Introduction
 Therapeutic Trials
Incidental Trials
 Summary and Conclusions
 REFERENCES
 
Clinical Results
There is substantial experience in the use of endocrine therapies for inoperable primary tumors, which might eventually result in their operability, and in patients with operable tumors who are unsuitable for surgery, for example, the frail and elderly (reviewed in Ref. 6 ). There is, however, much less experience in the use of these agents in patients for whom surgery is feasible. The major goal in the latter circumstances has been to downstage the tumor, for example, converting a tumor unsuited to breast-conserving surgery to a stage in which mastectomy is avoidable or providing a more cosmetic result in women in whom conservative surgery is already possible.

The importance of selecting only ER3 -positive patients for presurgical therapy is clear. In a study of women with large tumors and elderly patients who wished to avoid surgery, the Edinburgh group found that only 1 of 27 patients with ER-poor tumors compared with 35 of 62 (56%) patients with ER-rich tumors responded to primary endocrine therapy (premenopausal: oophorectomy or GnRH (Gonadotrophin Releasing Hormone) agonist; postmenopausal: aminoglutethimide, formestane, or tamoxifen; Ref. 7 ). In a recent multicenter comparative study between letrozole and tamoxifen, 28 patients entered on the basis of locally diagnosed ER positivity were deemed by central testing to be ER negative (8) . Only 1 of the 28 responded to the preoperative therapy.

The complete and partial response rates reported in a number of preoperative therapy studies in ER-positive patients are substantially higher (often higher than 70%) than those reported in metastatic disease (9) . This may be explained by the loss of responsiveness as a tumor becomes more advanced, has experienced cell selection through the metastatic process, and may have undergone a series of medical maneuvers. It also may reflect the difficulty in characterizing objective response at some metastatic sites. There have been no randomized trials to compare the effectiveness of cytotoxics and endocrine therapy in downstaging ER-positive breast carcinomas.

A duration of 3 months of preoperative therapy is supported by the observation that by this time 72 of 100 patients treated with tamoxifen had reductions in tumor volume of >25%, and only 1 patient progressed. Of the 27 patients with stable disease continuing on tamoxifen for a further 3 months, 4 responded, 5 progressed, and 18 remained stable (9) .

A series of nonrandomized relatively small-scale studies have been reported by Dixon (9) with tamoxifen (n = 65) and the aromatase inhibitors anastrozole (n = 23), letrozole (n = 36), and exemestane (n = 12). All patients had ER-positive tumors [>20 fmol/mg protein or histoscore > 80 (histoscore = percentage of cells intensity 1 x 1 + percentage of cells intensity 2 x 2 + percentage of cells intensity 3 x 3; range, 0–300)]. Overall, in this series of 136 patients, only 2 patients progressed over the 3-month presurgical period. The response rates (>50% reduction in tumor volume) were as follows: tamoxifen, 46%; anastrozole, 78%; letrozole, 89%; and exemestane, 83%. This is suggestive of a greater responsiveness to third-generation aromatase inhibitors compared with tamoxifen and provided support for the conduct of randomized trials.

Two randomized trials of a third-generation aromatase inhibitor and tamoxifen have been reported in the presurgical setting (5 , 10) . A relatively small study of vorozole versus tamoxifen (n = 53), which was powered on changes in biomarkers, reported response rates of 39% for tamoxifen and only 22% for vorozole. However, because of the small size of the study, the 95% confidence interval in the difference in response rates was -9% to +44%.

The other much larger study compared 4 months of presurgical therapy with either letrozole or tamoxifen in 337 patients diagnosed with ER-positive and/or PgR-positive, T2, T3, or T4a-c breast cancer. The response rates on clinical measurements were 36% for tamoxifen and 55% for letrozole (P < 0.001). Lower response rates were recorded for ultrasound and mammographic responses, but in each case, letrozole was superior. These data concur with the superiority of letrozole over tamoxifen reported in the metastatic setting (11) . For cases that were confirmed as receptor positive by central analysis, the clinical response rates were higher at 41% for tamoxifen and 60% for letrozole (8) .

Biological Results
Pretreatment Prediction of Response.
As described above, it is clear that few patients with ER-negative disease respond to primary endocrine treatment. It has also been reported that the proportional reduction in tumor volume at 3 months of women treated with primary tamoxifen was correlated with the pretreatment ER content (7) . In the comparative trial of letrozole and tamoxifen, there was a suggestion that patients with low positive ER levels (3–5 on the Allred scoring system) were less likely to respond to tamoxifen than letrozole. However, because a total of only 6.7% of the patient population was in these categories, the data do not allow a robust comparison (8) . We have reported that in addition to ER, pretreatment PgR positivity and low S-phase fraction as estimated in fine-needle aspirates are associated with response to tamoxifen (12) .

Of particular interest, the type 1 growth factor receptor status of tumors was reported to differentially influence their responsiveness to either tamoxifen or letrozole (8) . In patients with tumor that was positive for either epidermal growth factor receptor or HER2 or both, as well as being positive for ER or PgR or both, 4 of 19 (21%) patients responded to tamoxifen, and 15 of 17 (88%) patients responded to letrozole (P = 0.0004). The response rates in those negative for both growth factor receptors were 42% for tamoxifen and 54% for letrozole (P = 0.078). Our demonstration (13) of a reduced antiproliferative effect of endocrine therapy in HER2-positive hormone receptor-positive disease supported the partial resistance of this group of tumors, but this study did not have the power to distinguish the effects of different endocrine agents (see below). The apparent improved response of the growth factor receptor-positive group to the aromatase inhibitor requires confirmation to allow confident application of the data in terms of treatment selection. However, it does emphasize the value of the preoperative model in assessing the influence of biological parameters on treatment response.

Changes with Treatment.
The change in biomarkers with treatment is of interest in considering them as surrogate markers of response, particularly if these changes occur before the development of clinical response and are therefore predictive of it. In this regard, biomarkers that intimately relate to the process of tumor growth or regression might be expected to be good candidates as surrogates. We have therefore focused on the influence of these therapies on proliferation as measured by expression of the Ki67 antigen and apoptosis as measured by the terminal deoxynucleotidyl transferase-mediated nick end labeling assay. This approach was supported by the observation that endocrine treatment with either tamoxifen, idoxifene, or estrogen deprivation would lead to decreased proliferation and increased apoptosis in MCF-7 human breast cancer xenografts in immune-deprived mice (14) . It is notable from these xenograft studies, however, that reductions in Ki67 and/or increases in apoptosis are associated with reductions in the rate of tumor growth but not necessarily with objective regressions. Fig. 2Citation is a stylized version of these results and illustrates that approximately 3-fold increases in apoptosis accompanied by about 2-fold decreases in proliferation (with tamoxifen) only result in static disease in this rapidly growing tumor. Extrapolating this to the preoperative scenario, it would be expected that the likelihood of such changes predicting clinical response would depend in part on the growth rate of the tumor at presentation, a parameter that is not available to the clinical investigator. The data from clinical studies do nonetheless generally support a significant relationship between effects on proliferation and clinical response.



View larger version (17K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 2. Stylized figure of the growth changes occurring after tamoxifen treatment or estradiol (E2) withdrawal from MCF-7 tumor breast cancer xenografts. AI, apoptotic index. The full data are available in Johnston et al. (14) .

 
Clarke et al. (15) reported that there were significant reductions in Ki67 after a median 21 days of tamoxifen; Makris et al. (12) found that in responders to 3 months of tamoxifen, there was a median change in percentage of Ki67 of -4.8 after 14 days compared with -0.15 in nonresponders (P = 0.005). More recently, we reported trends to a correlation between reduced tumor volume after 3 months and reduced Ki67 after 14 days for both vorozole (r = 0.49; P = 0.09) and tamoxifen [r = 0.38; P = 0.17 (5) ]. Miller et al. (16) noted a more consistent reduction in Ki67 after 3 months with the aromatase inhibitors anastrozole and letrozole than with tamoxifen, and this may relate to the greater clinical response seen with the aromatase inhibitors.

We reported that in a small series of patients tamoxifen also increased apoptosis; additional studies have been consistent with this, but the increases are small and sometimes statistically insignificant and therefore not useful as a single surrogate marker. It may, however, be helpful in combination with Ki67 as an indicator of overall growth changes as a growth index or cell turnover index (5 , 17) . We noted an unexpected and significant fall in apoptosis after 2 weeks of treatment with vorozole that was not apparent after 12 weeks. This may have been due to the greater antiproliferative effect with vorozole than with tamoxifen but is contrary to our and others’ observations on the effects of estrogen deprivation in xenografts (14 , 18) . Such changes in the clinical situation are also likely to preclude the widespread use of changes in apoptosis as a surrogate indicator of response for endocrine therapy.

Changes in hormone receptor status have also been reported, and, to some extent, these vary with time and between endocrine agents. Staining indices for ER were reduced by about half by both tamoxifen and vorozole after 3 months (P = 0.001 for both), with lesser degrees of change being apparent at 2 weeks. These data are consistent with the results of Bajetta et al. (19) using 3 months of tamoxifen treatment, but they differ from the observations of estrogen deprivation in MCF-7 xenografts (20) . PgR levels are often increased after 2 weeks of tamoxifen and unchanged or increased after 12 weeks (5 , 16 , 21) , an effect that is reflective of the partial agonist activity of tamoxifen. This is in major contrast to the effects of vorozole, letrozole, and anastrozole, which result in near universal suppression of PgR after 2 and 12 weeks (5 , 16) . These effects are important to consider if receptor measurements are made for diagnostic purposes after preoperative therapy because they could lead to false-negative results.

The suppressive effects of treatment with aromatase inhibitors on intratumoral aromatase activity and intratumoral estrogen levels have also been demonstrated in the preoperative setting (22 , 23) . Detailed discussion of these data are outside of the context of this review, but the studies demonstrate the possibility of detailed study of the treatment target and its downstream products in the preoperative setting.

Future Opportunities
The therapeutic preoperative setting is particularly attractive for comparing new agents with existing agents, but it is not ethically acceptable for the evaluation of agents with no known therapeutic effect or a poor therapeutic effect as single agents. It is, however, attractive for the evaluation of agents that might be of benefit in combination with existing endocrine therapies. For example, the evaluation of signal transduction inhibitors such as growth factor receptor tyrosine kinase inhibitors in combination with hormonal agents is justified by preclinical data and will be tested in the near future.

The value of this scenario would be markedly enhanced if there was confidence that relative efficacy of preoperative therapy was predictive of relative efficacy in the adjuvant setting. In this regard, the presurgical comparison of anastrozole versus tamoxifen versus tamoxifen plus anastrozole (IMPACT) will report in 2003 and will be compared with the differences in relapse-free survival seen with these agents in the ATAC (Arimidex, Tamoxifen Alone or in Combination) trial (24) . Similarly, the data from the preoperative comparison of letrozole with tamoxifen cited above will eventually be comparable with the outcome data from the ongoing BIG-FEMTA (Breast International Group-Femara-Tamoxifen) adjuvant trial.


   Incidental Trials
Top
 ABSTRACT
 Introduction
 Therapeutic Trials
 Incidental Trials
Summary and Conclusions
 REFERENCES
 
General Points.
Studies of hormonal drugs that take place between the time of diagnosis and surgery are inevitably judged on the basis of surrogate end points of response. The most common primary end point is change in proliferation because this has been validated as having a relationship with clinical response as described above. Given that no medical (or other) treatment is generally delivered during this period, and no therapeutic advantage is envisaged by these studies, the randomization to a no-treatment or preferably a placebo arm is permissible and valuable. Changes in the parameter of interest could conceivably occur as a result of the initial biopsy (e.g., release of cytokines affecting an end point) or differences in the effects of fixation on tissue samples, which are frequently of different size at diagnosis, and surgery may cause artifactual changes that differ between the pre-and posttreatment biopsies.

Although no therapeutic advantage is envisaged by this treatment, it is ethically unacceptable to evaluate drugs for which there are insufficient safety data in this potentially curable population. This limits the use of this approach, which is at its most instructive early in drug development, when some initial evidence of efficacy is valuable, but inevitably, safety data are also limited at that time. It is particularly suited, however, to investigations of established agents where differential efficacy in biologically distinct subgroups is to be investigated. It is similarly valuable with agents for which there are substantive safety data from other disease settings but for which there are no available efficacy data (yet efficacy is a possibility) in breast cancer (e.g., cyclooxygenase-2 inhibitors).

Another consideration for the comparison of different agents in this short-term setting is the effect of pharmacokinetics. There are substantial differences between the half-lives and therefore time to steady state of many endocrine agents. For example, tamoxifen has a half-life of 7–10 days, and steady state is not approached for several weeks. In contrast, the aromatase inhibitors anastrozole and letrozole have half-lives of approximately 48 h. Whereas this is a theoretical concern, the data from the study of vorozole (half-life about 11 h) versus tamoxifen revealed similar further reductions in the primary end point Ki67 between 2 and 12 weeks for both agents (5) . The changes in Ki67 for individual patients and the relationship between the 2-week and 12-week changes are shown in Fig. 3Citation . Although further reductions occurred between the two time points, in general those patients whose tumor showed changes by 12 weeks also showed (a lesser) change at 2 weeks. There was a statistically significant relationship between the changes at the two time points (P = 0.01). Nonetheless, strategies for loading doses may be required to minimize the effects of pharmacokinetic differences.



View larger version (25K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 3. Changes in the percentage of Ki67 in individual patients after 2 weeks and 12 weeks of treatment with tamoxifen or vorozole (5) .

 
The availability of only a small diagnostic biopsy for biological analysis may be problematic for both therapeutic and incidental studies but is particularly severe in the latter setting, in which tumors and therefore the biopsy tend to be smaller. Studies may be conducted in which patients consent to a postdiagnostic pretreatment biopsy, but this is clearly a disadvantage that one would wish to avoid. An approach that is proving helpful in our own center and in Edinburgh4 is the request for consent for the taking of additional tissue at the time of the diagnostic biopsy for use in association with research protocols that the patient is likely to be eligible for. These protocols are subsequently fully discussed with the patient, and the tissue is not used unless participation occurs.

Efficacy Results.
The pure antiestrogen fulvestrant (ICI 182,780, Faslodex) was the first new drug to be evaluated in this short-term setting (25) . Fifty-six patients were randomized to no treatment or 6 or 18 mg/day fulvestrant delivered as an i.m. injection in propylene glycol-based formulation for 7 days. In patients on fulvestrant, ER levels fell significantly, confirming the down-regulation of ER seen in preclinical studies (26) . Ki67 levels fell from a median 3.2% to 1.1% (P < 0.05). These values of Ki67 are lower than those reported in the other studies described below, having been measured using a different antibody and differently prepared tissue. More recently, in a much larger study of 201 patients, single injections of fulvestrant of 50, 125, or 250 mg were randomized against daily tamoxifen or daily tamoxifen-placebo for between 14 and 21 days presurgically (27) . In the ER-positive population, there were dose-dependent statistically significant reductions in Ki67, but at no dose were these significantly different from tamoxifen. However, whereas there were no significant changes in apoptotic index with any of the treatments, there was a statistically significant greater reduction in the Ki67:apoptotic ratio (cell turnover index) by fulvestrant at 250 mg than by tamoxifen (P = 0.0003). This suggests that this index may be a more sensitive indicator of treatment effectiveness, but it has been evaluated in few other studies and has not been validated against clinical response.

Two other SERMs have been studied in this short-term preoperative setting, idoxifene and raloxifene, both in randomized, double-blind, placebo-controlled trials. In the idoxifene study, 77 patients were randomized, of whom 57 were ER positive and fully evaluable for Ki67 levels, which fell from 19.7% to 13.4% in the idoxifene-treated group (P = 0.0043) with no change in the placebo group (28) . The proportional change was greater in the group of patients whose tumors were also PgR positive, consistent with the known greater sensitivity of such tumors to antiendocrine agents (Fig. 4)Citation . Apoptosis was unaffected by treatment in the total group of ER-positive patients and also those additionally positive for PgR.



View larger version (23K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 4. Mean changes in Ki67 after 2 weeks of treatment with idoxifene according to ER and PgR status. The percentages shown in each panel show the mean change at 2 weeks relative to the pretreatment value (28) .

 
The variability of the primary end point in the absence of treatment is an important criterion when determining the statistical power of studies. With this in mind, the raloxifene study was powered on the variability determined in an earlier study in which Ki67 and apoptotic index were measured in pairs of core cuts taken at the same time from individual tumors (29) . A total of 167 patients were randomized to placebo, 60 or 600 mg/day raloxifene, and 143 had evaluable efficacy data (30) . There were significant reductions in Ki67 in the ER-positive group at both of the raloxifene doses relative to placebo, but no greater effect at the higher dose. Marginally greater effects were seen in the tumors also positive for PgR, and there were no significant effects on apoptosis. It is notable that this study was initiated to assess the anti-breast cancer activity of raloxifene at a time when there were no clinical data on its efficacy either in established tumors or in prevention. The subsequent data from these clinical efficacy studies of raloxifene and idoxifene (31 , 32) support the validity of antiproliferative studies in the preoperative setting for the prediction of clinical benefit.

Whereas these two studies and those for fulvestrant recruited their target number of patients, the difficulty in some settings to do so was emphasized in the interim publication by Singletary et al. (33) of a randomized trial of 2–4 weeks of tamoxifen or N-[4-hydroxyphenyl] retinamide in patients with ductal carcinoma in situ or early invasive breast cancer. Of the planned sample size of 100 patients, 52 were registered on study after 3 years of recruitment and the screening of 4514 women. The major reasons for nonparticipation were no evidence of malignancy (46%), ineligibility per protocol (13%), preoperative chemotherapy/tamoxifen (11%), and surgery scheduling conflict (8%). It may be significant that this trial is being conducted in the United States, and those described above were done in Europe and predominantly the United Kingdom. Differing approaches to initial treatment may influence recruitment rates.

Biological Results.
In addition to those end points considered as primary in the above trials, other data were collected, most frequently on PgR levels. The influence of therapy at 2 weeks on PgR levels is shown in Fig. 5Citation , including data from the studies of anastrozole and letrozole. This emphasizes that the agents that act to withdraw estrogen or as pure antagonists elicit major decreases in PgR. However, the SERMs tested led to an increase or no change in PgR. Whereas raloxifene and idoxifene led to lesser increases than tamoxifen, it is clear that there was no antagonist effect.



View larger version (14K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 5. Change in PgR levels after 2 weeks of treatment with the aromatase inhibitors vorozole and anastrozole (5 , 23) ; the SERMs tamoxifen, idoxifene, and raloxifene (5 , 28 , 30) ; and the pure antiestrogen fulvestrant (25) .

 
Levels of another protein considered to be estrogen dependent, pS2, were measured in the first of the fulvestrant studies, but no change was noted (25) , and this end point has not been included in subsequent studies. Similarly, no effect was seen of fulvestrant on immunocytochemical expression of epidermal growth factor receptor or transforming growth factor {alpha} (34) .

The possible importance of placebo or no-treatment controls in these short-term studies was noted above. This concern was supported by the decrease in ER levels seen in the placebo arm of the idoxifene, raloxifene, and the second fulvestrant studies, which was statistically significant in the first two studies. None of the other parameters were significantly different at surgery in the placebo arm (27, 28, 29) . The reason for this consistent change in ER is not known but might be due to the comparisons being made between surgical excision samples and core cuts at diagnosis, which would be expected to be subject to different rates of fixation.

Future Opportunities.
Opportunities exist in terms of the study of new agents and the application of new diagnostic tools to these and established agents. So far as new agents are concerned, the limitations considered above in relation to tolerability pertain but may allow the early evaluation of new anti-growth factor agents.

The identification of responsive and resistant subgroups has rarely been attempted to date, save for the analyses of ER- or PgR-positive and -negative tumors, but may be useful in establishing subgroups that may be targeted with alternative or additional medication. The principle of this approach was demonstrated by the assessment of antiproliferative effects of endocrine therapy in ER-positive patients according to HER2 status (13) . Although this involved measurements at both 2 and 12 weeks, it was clear that the effects were similar at both time points (Fig. 6A)Citation . This study not only supported the relative resistance of the HER2-positive patients but also suggested that this effect might be due in part to low ER levels in many HER2-positive tumors and in part to the impact of HER2 itself in those with high ER levels (Fig. 6B)Citation .



View larger version (37K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 6. A, change in mean ± SE Ki67 after 2 and 12 weeks of hormonal therapy in 115 breast tumors according to HER2 status. B, change in Ki67 after 2 weeks in the same 115 patients to pretreatment levels according to ER levels and HER2 status (13) .

 
It is likely that such exploratory studies will be markedly extended in the future with the application of modern gene screening techniques such as the use of cDNA microarrays. The impact of short treatment with cytotoxics has been studied with chips of 7000 genes using extracts of fine-needle aspirates, but this study was a proof of principle rather than an effort to identify new genes (35) . There have been no substantive publications on the impact of endocrine treatments on such expression profiles, but the recent publication of the validation of a method for using core needle biopsies in expression arrays is helpful in guiding such studies (36) . The use of these in pretreatment samples of short-term studies using change in proliferation as a surrogate end point of response could be a valuable alternative to their use in therapeutic presurgical studies with evaluation in terms of clinical response.


   Summary and Conclusions
Top
 ABSTRACT
 Introduction
 Therapeutic Trials
 Incidental Trials
 Summary and Conclusions
REFERENCES
 
The value of preoperative studies of endocrine therapy in the evaluation of new hormonal strategies is clear and is likely to be extended in the near future to the evaluation of these agents with new signaling agents. Although the studies to date have not identified any safety concerns, the widespread use of these approaches would be enhanced by the demonstration that they are not deleterious to the individual patient. This will need a large randomized trial of the type conducted with cytotoxic chemotherapy by National Surgical Adjuvant Breast and Bowel Project B18. Early changes in Ki67 as a measure of how effects on proliferation relate to clinical response are becoming widely accepted as a valid surrogate end point of efficacy and have already been used as such in a series of short-term presurgical studies. The judicious application of gene expression arrays to the biological samples available is likely to enhance the value of preoperative studies yet further.


   ACKNOWLEDGMENTS
 
I thank the large number of clinical collaborators who have contributed to the conduct of the trials cited, most particularly my colleagues at the Royal Marsden Hospital. I am also grateful to the laboratory staff who conducted the analyses, particularly Janine Salter, Margaret Hills, and Simone Detre.

Open Discussion

Dr. Adrian Lee: You mentioned that the last excisional biopsy may give a different result because of the fixation issue. Why didn’t you just take that excision biopsy and run some cores through it?

Dr. Mitch Dowsett: In the more recent studies, Mike Dixon has been doing that. It’s not that easy. It takes a bit more coordination to ask the surgeon to remember to take a core. If you get it when it’s out of the patient, it’s a slippery beast, and you’re liable to put the core through your finger as well. Those are pretty mundane issues, but they are there.

Dr. Lee: How much are you worried about it? How often have you seen Ki67 go down in a placebo sample?

Dr. Dowsett: Ki67 has not changed with placebo. The only issue we’ve identified concerns ER. PgR doesn’t show the same change. Where we have plenty of paraffin material, we can look back at the placebo studies and examine other end points we’re interested in; for phosphorylated HER2, for example, we’ve got antibodies. We don’t have the frozen tissues to address some of the markers we might want to look at in fresh tissue.

Dr. Carlos Arteaga: You mentioned that you had looked at the interpatient variability in your set of controls. So I assume you’ve only looked at Ki67 and apoptosis, correct? Are those blocks still available to see whether there are any changes in other markers, such as phospho-Akt, phospho-MAPK, etc.?

Dr. Dowsett: The blocks are available from the placebo studies, but as paraffin-embedded tissue. Some of this is multicenter cores, and some is in house. So some of it I’ve got good control on, some I haven’t.

Dr. Brian Long: Have you looked at the mechanisms of apoptosis, expression of the bcl-2 protein family, etc., that you had on the blocks?

Dr. Dowsett: In the presurgical chemotherapy setting, even within 24 hours, we’re getting doubling of apoptosis overall. It’s a very good model to begin to try to look at the biology of these different processes, and we have started doing so, but we’ve not done it in the endocrine setting. The surprise is, there is massive apoptosis in the MCF-7 model in our hands.

Dr. Long: Did you analyze those tumors while they were actively shrinking at 2 or 3 weeks?

Dr. Dowsett: We took the first sample while they were actively shrinking. We got a change in apoptosis there. The surprise to me was that even 12 weeks out there is this small nub of tumor and we still had greater apoptosis. I thought the apoptosis would have been more of a transient effect.

Dr. Arteaga: One reason why you could be seeing a lot of apoptosis in the MCF-7 model is you have a very high proportion of proliferating cells, which is strikingly different than what you see in tumors. Also, can you estimate the doubling time of those tumors? Because it’s very possible that some of those cells are destined to die but do not exhibit overt signs of apoptosis when you sample them. I would argue the 2-week window is too short to see apoptosis. Those cells may be destined to die, but they may still have to go through one or two cycles to then undergo programmed death.

Dr. Dowsett: We have not tried to estimate doubling time. By the time we get out to 12 weeks, we’re clearly getting true regression. The problem with just taking the 12-week sample is that you really don’t know whether you have a still responsive or a resistant population.

Dr. Kent Osborne: That’s the biggest problem with apoptosis. You don’t know whether to take it at 24 hours to see the changes you want or whether the timing of it is different—and it’s probably different for different cells in the population. When we tried to do this years ago, we didn’t have the staining method. By the old techniques, we never could demonstrate any apoptosis in our model with tamoxifen, not even a hint of it.


   FOOTNOTES
 
1 Presented at the Second International Conference on Recent Advances and Future Directions in Endocrine Manipulation of Breast Cancer, June 28–29, 2002, Cambridge, MA. Back

2 To whom correspondence should be addressed, at Academic Department of Biochemistry, Royal Marsden Hospital, London SW3 6JJ, United Kingdom. Phone: 44-20-7808-2887; Fax: 44-20-7376-3918; E-mail: mitch{at}icr.ac.uk Back

3 The abbreviations used are: ER, estrogen receptor; PgR, progesterone receptor; SERM, selective estrogen receptor modulator. Back

4 Michael Dixon, personal communication. Back


   REFERENCES
Top
 ABSTRACT
 Introduction
 Therapeutic Trials
 Incidental Trials
 Summary and Conclusions
 REFERENCES
 

  1. Fisher B., Saffer E., Rudock C., et al Effect of local or systemic treatment prior to primary tumor removal on the production and response to a serum growth-stimulating factor in mice. Cancer Res., 49: 2002-2004, 1989.[Abstract/Free Full Text]
  2. Fisher B., Bryant J., Wolmark N., et al Effect of preoperative chemotherapy on the outcome of women with operable breast cancer. J. Clin. Oncol., 16: 2672-2685, 1998.[Abstract]
  3. Esserman L., Hylton N., Yassa L., et al Utility of magnetic resonance imaging in the management of breast cancer: evidence for improved preoperative staging. J. Clin. Oncol., 17: 110-119, 1999.[Abstract/Free Full Text]
  4. Schelling M., Avril N., Nahrig J., et al Positron emission tomography using [18F]Fluorodeoxyglucose for monitoring primary chemotherapy in breast cancer. J. Clin. Oncol., 18: 1689-1695, 2000.[Abstract/Free Full Text]
  5. Harper-Wynne C. L., Sacks N. P., Shenton K., MacNeill F. A., Sauven P., Laidlaw I. J., Rayter Z., Miall S., Howes A., Salter J., Hills M. J., Lowe F. M., A’Hern R., Nasiri N., Doody D., Iqbal J., Dowsett M. Comparison of the systemic and intratumoral effects of tamoxifen and the aromatase inhibitor vorozole in postmenopausal patients with primary breast cancer. J. Clin. Oncol., 20: 1026-1035, 2002.[Abstract/Free Full Text]
  6. Cheung K. L., Howell A., Robertson J. F. Preoperative endocrine therapy for breast cancer. Endocr. Relat. Cancer, 7: 131-141, 2000.[Abstract]
  7. Miller W. R., Anderson T. J., Hawkins A., et al Neoadjuvant endocrine treatment: the Edinburgh experience Howell A. Dowsett M. eds. . Primary Medical Therapy for Breast Cancer: Clinical and Biological Aspects, 89-99, Elsevier New York 1999.
  8. Ellis M. J., Coop A., Singh B., et al Letrozole is more effective neoadjuvant endocrine therapy than tamoxifen for ErbB-1- and/or ErbB-2-positive, estrogen receptor-positive primary breast cancer: evidence from a Phase III randomized trial. J. Clin. Oncol., 19: 3808-3816, 2001.[Abstract/Free Full Text]
  9. Dixon J. M. Neoadjuvant therapy: surgical perspectives Miller W. R. Ingle J. N. eds. . Endocrine Therapy in Breast Cancer, 197-212, Marcel Dekker, Inc. New York 2002.
  10. Eiermann W., Paepke S., Appfelstaedt J., et al Preoperative treatment of postmenopausal breast cancer patients with letrozole: a randomized double-blind multicenter study. Ann. Oncol., 12: 1527-1532, 2001.[Abstract/Free Full Text]
  11. Mouridsen H., Gershanovich M., Sun Y., et al Superior efficacy of letrozole versus tamoxifen as first-line therapy for postmenopausal women with advanced breast cancer: results of a Phase III study of the International Letrozole Breast Cancer Group. J. Clin. Oncol., 19: 2596-2606, 2001.[Abstract/Free Full Text]
  12. Makris A., Powles T. J., Allred D. C., et al Changes in hormone receptors and proliferation markers in tamoxifen treated breast cancer patients and the relationship with response. Breast Cancer Res. Treat., 48: 11-20, 1998.[CrossRef][Medline]
  13. Dowsett M., Harper-Wynne C., Boeddinghaus I., et al HER-2 amplification impedes the antiproliferative effects of hormone therapy in estrogen receptor-positive primary breast cancer. Cancer Res., 61: 8452-8458, 2001.[Abstract/Free Full Text]
  14. Johnston S. R. D., Boeddinghaus I. M., Riddler S., et al Idoxifene antagonizes estradiol-dependent MCF-7 breast cancer xenograft growth through sustained induction of apoptosis. Cancer Res., 59: 3646-3651, 1999.[Abstract/Free Full Text]
  15. Clarke R. B., Laidlaw I. J., Jones L. J., et al Effect of tamoxifen on Ki67 labelling index in human breast tumours and its relationship to oestrogen and progesterone receptor status. Br. J. Cancer, 67: 606-611, 1993.[Medline]
  16. Miller W. R., Dixon J. M., Cameron D. A., et al Biological and clinical effects of aromatase inhibitors in neoadjuvant therapy. J. Steroid Biochem. Mol. Biol., 79: 103-107, 2001.[CrossRef][Medline]
  17. Bundred N., Anderson E., Nicholson R. I., et al Fulvestrant, an estrogen receptor downregulator, reduces cell turnover index more effectively than tamoxifen. Proc. Am. Soc. Clin. Oncol., 20: 416a 2001.
  18. Kyprianou N., English H. F., Davidson N. E., et al Programmed cell death during regression of the MCF-7 human breast cancer following estrogen ablation. Cancer Res., 51: 162-166, 1991.[Abstract/Free Full Text]
  19. Bajetta E., Celio L., Di Leo A., et al Effects of short-term pre-operative tamoxifen on steroid receptor and Ki-67 expression in primary breast cancer: an immunocytochemical study. Int. J. Oncol., 12: 853-858, 1998.[Medline]
  20. Detre S., Salter J., Barnes D. M., et al Time-related effects of estrogen withdrawal on proliferation- and cell death-related events in MCF-7 xenografts. Int. J. Cancer, 81: 309-313, 1999.[CrossRef][Medline]
  21. Howell A., Harland R. N., Barnes D. M., et al Endocrine therapy for advanced carcinoma of the breast: effect of tumor heterogeneity and site of biopsy on the predictive value of progesterone receptor estimations. Cancer Res., 47: 296-299, 1987.[Abstract/Free Full Text]
  22. Miller W. R., Dixon J. M. Local endocrine effects of aromatase inhibitors within the breast. J. Steroid Biochem. Mol. Biol., 79: 93-102, 2001.[CrossRef][Medline]
  23. Geisler J., Detre S., Berntsen H., et al Influence of neoadjuvant anastrozole (Arimidex) on intratumoral estrogen levels and proliferation markers in patients with locally advanced breast cancer. Clin. Cancer Res., 7: 1230-1236, 2001.[Abstract/Free Full Text]
  24. The ATAC Trialists’ Group. Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early breast cancer: first results of the ATAC randomised trial. Lancet, 359: 2131-2139, 2002.[CrossRef][Medline]
  25. DeFriend D. J., Howell A., Nicholson R. I., et al Investigation of a new pure antiestrogen (ICI 182780) in women with primary breast cancer. Cancer Res., 54: 408-414, 1994.[Abstract/Free Full Text]
  26. Wakeling A. E., Dukes M., Bowler J. A. potent specific pure antiestrogen with clinical potential. Cancer Res., 51: 3867-3873, 1991.[Abstract/Free Full Text]
  27. Robertson J. F., Nicholson R. I., Bundred N. J., et al Comparison of the short-term biological effects of 7{alpha}-[9-(4,4,5,5,5-pentafluoropentylsulfinyl)-nonyl]estra-1,3,5,(10)-triene-3,17ß-diol (Faslodex) versus tamoxifen in postmenopausal women with primary breast cancer. Cancer Res., 61: 6739-6746, 2001.[Abstract/Free Full Text]
  28. Dowsett M., Dixon J. M., Horgan K., et al Antiproliferative effects of idoxifene in a placebo-controlled trial in primary human breast cancer. Clin. Cancer Res., 6: 2260-2267, 2000.[Abstract/Free Full Text]
  29. Ellis P. A., Smith I. E., Detre S., et al Reduced apoptosis and proliferation and increased Bcl-2 in residual breast cancer following preoperative chemotherapy. Breast Cancer Res. Treat., 48: 107-116, 1998.[CrossRef][Medline]
  30. Dowsett M., Bundred N. J., Decensi A., et al Effect of raloxifene on breast cancer cell Ki67 and apoptosis: a double-blind, placebo-controlled, randomized clinical trial in postmenopausal patients. Cancer Epidemiol. Biomark. Prev., 10: 961-966, 2001.[Abstract/Free Full Text]
  31. Gradishar W., Glusman J., Lu Y., et al Effects of high dose raloxifene in selected patients with advanced breast carcinoma. Cancer (Phila.), 88: 2047-2053, 2000.[CrossRef][Medline]
  32. Johnston S. R. D., Gorbunova L., Evans T. R. J., et al A multi-double-blind randomised Phase III trial of idoxifene versus tamoxifen as first-line endocrine therapy for metastatic breast cancer. Proc. Am. Soc. Clin. Oncol., 20: 29 2001.
  33. Singletary E., Lieberman R., Atkinson N., et al Novel translational model for breast cancer chemoprevention study: accrual to a presurgical intervention with tamoxifen and N-[4-hydroxyphenyl] retinamide. Cancer Epidemiol. Biomark. Prev., 9: 1087-1090, 2000.[Abstract/Free Full Text]
  34. McClelland R. A., Manning D. L., Gee J. M., et al Effects of short-term antiestrogen treatment of primary breast cancer on estrogen receptor mRNA and protein expression and on estrogen-regulated genes. Breast Cancer Res. Treat., 41: 31-41, 1996.[CrossRef][Medline]
  35. Sotiriou C., Powles T. J., Dowsett M., et al Gene expression profiles derived from fine needle aspiration correlate with response to systemic chemotherapy in breast cancer. Breast Cancer Res., 4: R3 2002.[CrossRef][Medline]
  36. Ellis M., Davis N., Coop A., et al Development and validation of a method for using breast core needle biopsies for gene expression microarray analyses. Clin. Cancer Res., 8: 1155-1166, 2002.[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 Clin TrialsHome page
W. Demark-Wahnefried, S. L George, B. R Switzer, D. C Snyder, J. F Madden, T. J Polascik, M. T Ruffin IV, and R. T Vollmer
Overcoming challenges in designing and implementing a phase II randomized controlled trial using a presurgical model to test a dietary intervention in prostate cancer
Clinical Trials, June 1, 2008; 5(3): 262 - 272.
[Abstract] [PDF]

Home page
 Clin. Cancer Res.Home page
M. J. Ellis
Neoadjuvant Endocrine Therapy as a Drug Development Strategy
Clin. Cancer Res., January 1, 2004; 10(1): 391S - 395S.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Dowsett, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Dowsett, M.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Meeting Abstracts Online