Effect of subsequent chemotherapy on overall survival in first-line chemotherapy with targeted agents for patients with metastatic colorectal cancer: Systematic review and meta-analysis of randomized control trials.

Abstract

782 Background: One of recent standard first line chemotherapies for metastatic colorectal cancer is doublet of cytotoxic agents, fluorouracil and oxaliplatin or irinotecan, in combination with target agent, bevacizumab, or anti-EGFR antibody as cetuximab or panitumumab for KRAS or RAS wild type (WT). In this decade, nevertheless progression free survival (PFS) of clinical trials was little improved, overall survival (OS) had been increased. Methods: We analyzed data from 14 recently published phase III randomized clinical trials in mCRC to correlate the percentage of patients receiving subsequent chemotherapy with the reported OS. Results: Median PFS and OS were 10.3 and 25.0 months, respectively. In all comer trials, median OS is significantly correlated with the percentage of patients who received subsequent chemotherapy after first line chemotherapy of their disease [regression coefficient (R2) = 0.85 p = 0.0018]. In trials with KRAS WT, a correlation between OS and the rate of subsequent therapy was modest [r2 = 0.605, p = 0.0637]. Median PFS and RR were not correlated with median OS. Conclusions: Our results support the strategy of making salvage chemotherapy available to all patients with advanced CRC to maximize OS. In addition, our findings suggest that, with the availability of effective salvage options, PFS might no longer be regarded as the appropriate surrogate end point of OS by which to assess the efficacy of a palliative first-line treatment in CRC.