Abstract P6-10-03: Does participation in clinical trials influence on survival in patients with metastatic breast cancer?

Abstract

Abstract Background Recently, many clinical trials (TRIAL) especially incorporated with molecular-targeted agents are being conducted in treatment for breast cancer worldwide. However, the relation of participating clinical trials with survival has not been actively studied. This study was designed to evaluate whether participation in clinical trials could improve overall survival (OS) or not in patients with metastatic breast cancer (MBC), compared with conventional treatment. Method Korean Cancer Study Group (KCSG) has successfully established Nationwide Cohort in KOREA to conduct diachronic analysis (KCSG BR 14-07). Clinical data for patients with MBC were collected from this Cohort. OS was defined as the time duration from first diagnosis of metastasis to any cause of death. This work is supported by National Strategic Coordinating Center for Clinical Research (H110C2020). Results A total of 575 patients with metastatic breast from 26 institutes in KOREA cancer MBC were consequently enrolled between September 2014 and May 2015. 156 (27.1%) of patients were enrolled to at least one or more clinical trials and 419 patients received only conventional treatment (CONV). Age, hormone status, HER2 status, initial pathologic stage, metastasis versus recurrence, adjuvant treatment, ECOG performance status (PS) (0, 1 vs 2 or more) were similar between TRIAL and CONV. 30% of trials were associated with HER2-targeted agents. As initial treatment, chemotherapy was more frequently used in TRIAL (85.9%) than in CONV (79.0%) (P=0.038). Number of regimens of chemotherapy was greater in TRIAL (2.9+/-1.8) than CONV (2.1+/-1.6) (P<0.001). Number of regimens of endocrine therapy (E) was similar between TRIAL (1.4+/-0.6) and CONV (1.5+/-0.7) (P=0.474). Overall survival of all patients was 16.2 months (95% CI, 14.1-18.1). TRIAL showed significant prolongation of survival, compared with CONV [21.1 (95% CI, 17.7-24.6) vs 15.1 months (95% CI, 13.1-17.2); P=0.005]. The differences in OS was constantly observed in HER2-positive [23.8 (16.7-30.9) vs 17.2 months (95% CI, 12.4-21.9); P=0.018] and Triple-negative [15.4 (10.5-20.3) vs 12.0 months (95% CI, 10.2-13.8); P=0.025]. In multivariate analysis, initial metastasis, hormone status, ECOG PS did not influence on OS between TRIAL and CONV (P=0.849) Conclusion Participating in clinical trials could be associated with prolongation of survival. This results constantly maintained in HER2-positive and triple-negative MBC. These findings suggested that clinical trials are useful for the patients with MBC, even if the patients do not complete the standard treatment. Citation Format: Kim T-Y, Sohn JH, Kim S-B, Yoon JH, Kim GM, Lee KH, Koh S-J, Park YH, Lee SE, Chae Y, Lee KS, Lee KE, Won HS, Kim JH, Jeong J, Park KH, Cho EK, Im Y-H, Im S-A, Jung KH. Does participation in clinical trials influence on survival in patients with metastatic breast cancer?. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-10-03.