Abstract
BACKGROUND: The ML18174 study, which showed benefits of bevacizumab (BEV) continuation beyond progression (BBP) for metastatic colorectal cancer (mCRC), excluded patients with first-line progression-free survival (PFS) shorter than 3 months. The present study was conducted to evaluate the efficacy of second-line chemotherapy after early disease progression during first-line chemotherapy containing bevacizumab. METHODS: The subjects of this study were mCRC patients who experienced disease progression < 100 days from commencement of first-line chemotherapy containing BEV initiated between Apr 2007 and Dec 2016. Second-line chemotherapy regimens were classified into two groups with and without BEV/other anti-angiogenic agents (BBP and non-BBP) and efficacy and safety were compared using univariate and multivariate analysis. RESULTS: Sixty-one patients were identified as subjects of this study. Baseline characteristics were numerically different between BBP (n = 37) and non-BBP (n = 25) groups, such as performance status (0-1/> 2/unknown: 89/8/3 and 56/40/4%), RAS status (wild/mutant/unknown: 32/54/16 and 76/16/8%). Response rate was 8.6% in BBP group and 9.1% in non-BBP group (p = 1.00). Median PFS was 3.9 months in BBP group and 2.8 months in non-BBP group (HR [95%CI]: 0.79 [0.46-1.34], p = 0.373, adjusted HR: 0.87 [0.41-1.82], p = 0.707). Median overall survival was 8.5 months in BBP group and 5.4 months in non-BBP group (HR 0.66 [0.38-1.12], p = 0.125, adjusted HR 0.53 [0.27-1.07], p = 0.078). CONCLUSION: In mCRC patients who experienced early progression in first-line chemotherapy, second-line chemotherapy showed poor clinical outcomes regardless use of anti-angiogenic agents.