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 Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Zhang, H. Articles by Tsujii, H. Search for Related Content PubMed PubMed Citation Articles by Zhang, H. Articles by Tsujii, H.

[¹¹C]Methionine Positron Emission Tomography and Survival in Patients with Bone and Soft Tissue Sarcomas Treated by Carbon Ion Radiotherapy

¹ Department of Medical Imaging, ² Clinical Diagnosis Section, and ³ Clinical Oncology Section, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan

Purpose: The development of the novel carbon ion radiotherapy (CIRT) in the treatment of refractory cancers has resulted in the need for a way to accurately evaluate patient prognosis. We evaluated whether L-[methyl-¹¹C]-methionine (MET) uptake and its change after CIRT were the early survival predictors in patients with unresectable bone and soft tissue sarcomas.

Experimental Design: MET positron emission tomography was prospectively performed in 62 patients with unresectable bone and soft tissue sarcomas before and within 1 month after CIRT. Tumor MET uptake was measured with the semiquantitative tumor:nontumor ratio (T/N ratio). The MET uptake in the tumor and relevant clinical parameters were entered into univariate and multivariate survival analysis.

Results: The overall median survival time was 20 months. Patients with a baseline T/N ratio of 6 had a significant better survival than patients with a baseline T/N ratio >6 (2-year survival rate: 69.4% versus 32.3%; P = 0.01). Patients with a post-CIRT ratio of 4.4 had a better survival than that with a post-CIRT ratio >4.4 (2-year survival rate: 63.7% versus 41.3%; P = 0.01). A significant higher survival rate was observed in patients with post-therapeutic MET uptake change of >30% than patients in lower change group (2-year survival rate: 74.6% versus 41.6%; P = 0.049). The multivariate analysis showed that both baseline and post-CIRT T/N ratio were statistically significant independent predictors of patient survival. Tumors with larger T/N ratio had a significantly poorer prognosis.

Conclusions: MET uptake as measured by either baseline or post-CIRT T/N ratio was an independent predictor of survival in patients with bone and soft tissue sarcomas treated by carbon ion radiotherapy, whereas post-therapeutic MET uptake change might have potential value for the same purpose.