Systemic Therapy for Metastatic Colorectal Cancer: Patterns of Chemotherapy and Biologic Therapy Use in US Medical Oncology Practice

Purpose: With the emergence of new chemotherapies and biologic agents in the treatment of metastatic colorectal cancer (mCRC), the optimal combination and sequencing of these therapies are yet to be determined. This study examined the extent and pattern of chemotherapy and biologic therapy use by line of treatment. Biologic continuation and dose escalation were also examined. Methods: This study used an integrated electronic medical record database of 91 US oncology practices. Records were analyzed for 1,655 adult patients with mCRC who were treated from January 1, 2004 to January 31, 2008 with systemic therapy and could be observed for >= 3 months beyond their diagnosis of metastatic disease. Combination and sequence of individual drugs and regimens were examined. Results: For first-line therapy, the most common chemotherapy backbone was infused fluorouracil, leucovorin, and oxaliplatin (FOLFOX; 40.5% of patients), and the most common treatment regimen was FOLFOX plus bevacizumab (26.2%). For second-line therapy, fluorouracil, leucovorin, and irinotecan (FOLFIRI) was the most common chemotherapy backbone (25.7%), and FOLFIRI plus bevacizumab was the most common treatment regimen (18.3%). Across the study period, 68.6%, 22%, and 7% of patients received bevacizumab, cetuximab, and panitumumab, respectively. Among 412 patients receiving bevacizumab-containing regimens as first-line therapy who then received second-line therapy, 58% continued receiving bevacizumab, with dose escalation observed in 44%. Conclusion: The most commonly used chemotherapy backbones for mCRC treatment were first-line FOLFOX and second-line FOLFIRI. Bevacizumab was the most frequently administered biologic therapy. Continuation and dose escalation with bevacizumab were frequently observed across lines of therapy.