Effectiveness of Maintenance Therapy After the End of the First Line of Treatment for Patients With Metastatic Colorectal Cancer – The Results of a Population-Based Study

Abstract

Aim.To evaluate the effectiveness of different regimens of maintenance chemotherapy after the first line of treatment for patients with metastatic colorectal cancer.Materials and methods.We performed retrospective analyses of the data from 432 patients from 17 clinics in 14 regions of the Russian Federation who started systemic therapy for metastatic cancer in 2013. The main inclusion criterion was objective response or stabilization after the first 16 weeks of first-line therapy. Four groups of patients were compared, depending on the nature of maintenance therapy: those receiving fluoropyrimidines, a combination of fluoropyrimidines with bevacizumab, monotherapy of bevacizumab and monotherapy of anti-EGFR antibodies. The main criteria for assesment of the effectiveness of treatment were progression-free survival and overall survival. The statistical analysis was performed with the SPSS 20.0 sof tware package.Results.Maintenance therapy after completion of the first 16 weeks of the 1st line of chemotherapy was administered in 126 patients, most of them were treated with fluoropyrimidines (53.1 %). The median overall survival in the maintenance group was 27 versus 21 months in the observation group, p=0.01, HR=0.78 (95 % CI 0.6–1.02) Median progression-free survival in the maintenance group was 11 vs 7 months in the observation group (p<0.001, HR=0.6, 95 % CI 0.5–0.8). The worst results of progression-free survival were observed in the group with monotherapy of bevacizumab – median was 10 months versus 12 months in the fluoropyrimidine monotherapy group, 10 months for the combination of fluoropyrimidine with bevacizumab and 14 months for monotherapy of the anti-EGFR (p=0,9, HR=1.0, 95 % CI 0.9–1.2).Conclusions.There were no statistical differences in survival with different regimens of maintenance therapy. Monotherapy of bevacizumab in maintenance treatment was associated with the worst sur vival rates.