Clinical Practice Patterns in Chemotherapeutic Treatment Regimens for Metastatic Colorectal Cancer

Abstract

Background: The treatment of patients with metastatic colorectal cancer (mCRC) has evolved during the past 2 decades, and patient survival has increased. Consequently, patients are exposed to more chemotherapeutic agents and regimens. Little is known about therapeutic drug sequencing and the factors influencing these choices.

Materials and methods: An observational, retrospective medical record review was conducted of patients with newly diagnosed adult mCRC from January 2002 to September 2013 identified in the McGill University-Jewish General Hospital's local tumor registry. All patients presented with mCRC (stage IV) and received ≥ 2 cycles and/or ≥ 28 days of first-line chemotherapy. The patient demographics, CRC characteristics, treatment patterns, and outcomes were recorded. The reason for changing or halting therapy was also reported.

Results: Of the 215 patients who underwent treatment, 74.4% received second-line, 36% third-line, and 16.3% fourth-line treatment. In total, 88% received ≥ 3 classes of cytotoxic chemotherapy and 80% received ≥ 1 biologic agent. The most common first-line treatment was FOLFOX (5-fluorouracil, leucovorin, oxaliplatin) (47.4%) or CAPOX (capecitabine, oxaliplatin) (28.8%), and more than one half received bevacizumab (56%). Among the second- and third-line treatments, FOLFIRI (irinotecan, 5-fluorouracil, leucovorin) was the most common (40.3% and 30.3%, respectively), and bevacizumab was the most frequently used biologic agent (48.1% and 39.2%, respectively). For fourth-line treatment and beyond, most patients participated in clinical trials (45.7%) or received panitumumab monotherapy (31.4%). Across the first 4 therapy lines, disease progression was the primary motive for discontinuation (39.5%, 53.8%, 58.2%, and 37.1%).

Conclusion: FOLFOX was the most common first-line and FOLFIRI the most common second- and third-line mCRC therapy. Bevacizumab was the most frequently used targeted therapy across all 3 treatment lines. Therapy discontinuation was primarily due to disease progression.

Keywords: Attrition; Biologic; Discontinuation of therapy; Longitudinal; Real world.