Comparative analysis of different maintenance regimens after first-line induction in patients with metastatic colorectal cancer.

Abstract

789 Background: Although, previous trials have demonstrated the benefits of maintenance chemotherapy for unresectable metastatic colorectal cancer (MCRC), the optimal maintenance regimen with acceptable safety profile is still undetermined. The primary objective of this meta-analysis was to compare the effectiveness of the most common clinically used maintenance regimens after first line therapy in MCRC. Methods: Among 52 prospective studies published 2009-2017, 14 were qualified for inclusion. Random-effect model was used for pooled effects within different categories include those with no maintenance treatment versus different maintenance regimens (Bevacizumab, capecitabine, bevacizumab plus capecitabine, bevacizumab plus erlotinib, and cetuximab). Primary endpoint was median progression free survival (PFS), and secondary endpoint was median overall survival (OS). All statistical tests were two-sided and p values < 0.05 were considered significant. Results: 14 studies with 3553 patients (57% males) were included in final analysis. Induction treatment was 5-FU or capecitabine - based chemotherapy with either oxaliplatin or irinotecan with or without bevacizumab. After stratifying for induction status, patients who did not receive treatment had worse PFS compared to maintenance treatment [pooled median PFS 3.52 months, 95% CI (2.97- 4.07) Vs 5.08 months, 95% CI (4.59- 5.57), z-test adjusted p-value 0.0005]. Among different maintenance regimens, capecitabine /bevacizumab combination showed better PFS [pooled median PFS 6.87 month, 95% CI (5.17- 8.57)], however the results were not significant (z test adjusted p-value 0.1383). No statistical significant difference in median OS between maintenance regimens. Conclusions: MCRC patients who did not receive maintenance treatment had shorter PFS. Although the superiority of bevacizumab plus capecitabine maintenance cannot be confirmed, there was a trend towards better PFS. This study suggests that bevacizumab plus capecitabine may be an appropriate maintenance option after first induction therapy depending on the tolerability and compliance with oral capecitabine.