This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Wittner, B. S. Articles by Ramaswamy, S. PubMed PubMed Citation Articles by Wittner, B. S. Articles by Ramaswamy, S.

Analysis of the MammaPrint Breast Cancer Assay in a Predominantly Postmenopausal Cohort

Authors' Affiliations: ¹ Massachusetts General Hospital Cancer Center; Departments of ² Medicine and ³ Pathology, Harvard Medical School, Boston, Massachusetts and ⁴ Agendia BV; Divisions of ⁵ Molecular Carcinogenesis and ⁶ Diagnostic Oncology, Netherlands Cancer Institute, Amsterdam, the Netherlands

Requests for reprints: Sridhar Ramaswamy, Massachusetts General Hospital Cancer Center, 185 Cambridge Street, Boston, MA 02114. Phone: 617-643-3140; Fax: 617-643-3170; E-mail: sridhar{at}mgh.harvard.edu.

Purpose: Most node-negative breast cancer patients are older and postmenopausal and are increasingly being offered adjuvant chemotherapy despite their low overall risk of distant relapse. A molecular diagnostic test with high negative predictive value (NPV) for distant metastasis in this subgroup would spare many older breast cancer patients adjuvant treatment.

Experimental Design: We determined the NPV and positive predictive value of the MammaPrint assay in breast cancer patients who were consecutively diagnosed and treated at the Massachusetts General Hospital between 1985 and 1997. Primary tumors from 100 patients with node-negative, invasive breast cancer (median age, 62.5 years; median follow-up, 11.3 years) were subjected to MammaPrint analysis and classified as being at either low or high risk for distant metastasis.

Results: The MammaPrint 70-gene signature displayed excellent NPV as in previous studies, correctly identifying 100% of women at low risk for distant metastases at 5 years. However, this assay had a lower positive predictive value (12% at 5 years) than previously observed.

Conclusions: The MammaPrint assay was originally designed to identify younger breast cancer patients at low risk for distant metastasis, who might consequently be spared systemic treatment. We show here that the same signature has a very high NPV for distant recurrence after adjuvant treatment in older breast cancer patients.