Purpose: Maintenance therapy after oxaliplatin withdrawal is useful in patients with metastatic colorectal cancer (mCRC). This study aimed to investigate the timing of discontinuation or reintroduction of oxaliplatin and the optimal maintenance therapy regimen for survival. Materials and Methods: PubMed and conference abstracts were searched to select phase II and III trials of first-line oxaliplatin-containing therapy with or without bevacizumab using maintenance therapy for mCRC. Correlations of median overall survival (OS) with induction therapy regimens, induction therapy duration, maintenance therapy regimens (fluoropyrimidine plus bevacizumab [FP+Bev], FP/Bev alone, and no treatment), and oxaliplatin reintroduction were investigated using correlation and weighted multivariate regression analyses. Results: Twenty-two treatment arms were analyzed, including 2,581 patients. The maintenance therapy regimen FP+Bev showed the strongest correlation with a prolonged OS (Spearman’s partial correlation coefficient=0.42), and the other three variables correlated weakly with the OS. The maintenance therapy regimen significantly interacted with the induction chemotherapy duration (p=0.019). The predicted OS for FP+Bev crossed the lines of FP/Bev alone at 18 weeks of induction therapy, and of no treatment at 23 weeks. The corresponding OS at 12 and 27 weeks of induction therapies were 28.6 and 24.2 months for FP+Bev, 25.9 and 28.8 months for FP/Bev alone, and 20.5 and 27.5 months for no treatment. Conclusion The optimal maintenance therapy regimen for the OS is a continuous induction therapy as long as possible followed by FP/Bev alone and switching to FP+Bev within approximately 4 months if induction therapy is discontinued.

Purpose: Maintenance therapy after oxaliplatin withdrawal is useful in patients with metastatic colorectal cancer (mCRC). This study aimed to investigate the timing of discontinuation or reintroduction of oxaliplatin and the optimal maintenance therapy regimen for survival. Materials and Methods: PubMed and conference abstracts were searched to select phase II and III trials of first-line oxaliplatin-containing therapy with or without bevacizumab using maintenance therapy for mCRC. Correlations of median overall survival (OS) with induction therapy regimens, induction therapy duration, maintenance therapy regimens (fluoropyrimidine plus bevacizumab [FP+Bev], FP/Bev alone, and no treatment), and oxaliplatin reintroduction were investigated using correlation and weighted multivariate regression analyses. Results: Twenty-two treatment arms were analyzed, including 2,581 patients. The maintenance therapy regimen FP+Bev showed the strongest correlation with a prolonged OS (Spearman’s partial correlation coefficient=0.42), and the other three variables correlated weakly with the OS. The maintenance therapy regimen significantly interacted with the induction chemotherapy duration (p=0.019). The predicted OS for FP+Bev crossed the lines of FP/Bev alone at 18 weeks of induction therapy, and of no treatment at 23 weeks. The corresponding OS at 12 and 27 weeks of induction therapies were 28.6 and 24.2 months for FP+Bev, 25.9 and 28.8 months for FP/Bev alone, and 20.5 and 27.5 months for no treatment. Conclusion The optimal maintenance therapy regimen for the OS is a continuous induction therapy as long as possible followed by FP/Bev alone and switching to FP+Bev within approximately 4 months if induction therapy is discontinued.