Survival analysis of metastatic colorectal cancer patients who were treated with the five major therapeutic agents over the course of disease

Abstract

Purpose: Exposure to all active agents may be more important than specific sequence of drug administration in the treatment of patients with metastatic colorectal cancer (mCRC). The purpose of this study was to evaluate the overall survival (OS) of mCRC patients who were treated with all 5 major therapeutic agents used in this malignancy. Methods: We retrospectively reviewed the medical records of 395 mCRC patients referred to our clinic. The study included patients who received 5-fluorouracil (5-FU)-, irinotecan- or oxaliplatin-based chemotherapy and at least 3 cycles of bevacizumab and 4 weeks of cetuximab sequentially in various combinations. Results: Forty mCRC patients received the 5 major therapeutic agents effectively and sequentially, and their mean OS was 26.43 +/- 2.04 months. The 3- and 4- year OS survival rates were 26.7% and 16.7%, respectively. When survival analysis was limited to the metastatic patients with at least 6 cycles of bevacizumab therapy in addition to standard duration of other chemotherapeutic agents (N=33), the mean OS was 26.7 +/- 2.38 months. With a further survival analysis limited to metastatic patients who were treated with at least both 6 cycles of bevacizumab and 8 weeks of cetuximab in addition to other therapies (N=17), the mean OS was 44.8 +/- 11.03 months. Conclusion: This study demonstrated that in mCRC patients there may be a significant survival advantage if an adequate tumor response was achieved with all major therapeutic agents. Therefore, we believe that we should treat our patients with the 5 major therapeutic drugs as effectively as possible.