Maintenance therapy in patients with unresectable metastatic colorectal cancer receiving oxaliplatin plus antiangiogenic-based induction regimen: a study cohorts analysis.

Objectives: Maintenance therapy is frequently proposed to patients with unresectable metastatic colorectal cancer (mCRC). However, the optimal regimen has not been defined, and studies have failed to characterize the patients who benefit from the maintenance strategy.

Research design and methods: A systematic search of studies of maintenance was performed. Prospective studies that evaluated the progression-free survival (PFS) from the start of induction to progression and reported overall survival (OS) were selected. The efficacy of induction + maintenance therapy was assessed by the PFS/OS ratio. Twenty-one baseline variables were extracted and a linear regression was performed, separating cohorts in which maintenance included antiangiogenic agent (AAG)-based or fluoropyrimidine (FP)-based regimen.

Results: Twenty-three study cohorts related to 18 trials were selected. Analysis of variables versus PFS/OS ratio showed a significant relationship with sex (23 cohorts; β = -0.0082, p-value = 0.016). In the 19 cohorts that received an AAG-based regimen, a benefit was found for females, patients receiving longer oxaliplatin-based induction chemotherapy, lung metastases, while in the 17 cohorts that received an FP-based treatment only patients without a previous primary tumor resection reported higher PFS/OS.

Conclusions: Despite the heterogeneity of the studies, female sex was associated with a more pronounced effect of maintenance regimens, particularly AAG-based.