Primary tumor location and survival in colorectal cancer: A retrospective cohort study
Himani Aggarwal, Kristin M. Sheffield, Li Li, David Lenis, Rachael Sorg, Afsaneh Barzi, Rebecca A. Miksad
Abstract
BACKGROUND: Primary tumor location is a prognostic factor for metastatic colorectal cancer (mCRC). Post hoc analyses of mCRC clinical trials, including FIRE-3, CALGB/SWOG 80405, suggest that primary tumor location is also predictive of survival benefit with cetuximab or bevacizumab in combination with 5-fluorouracil-based chemotherapy. AIM: Evaluate prognostic/predictive roles of primary tumor location in real-world mCRC patients treated with cetuximab or bevacizumab plus 5-fluorouracil-based chemotherapy. METHODS: wild-type mCRC who initiated first-line therapy with cetuximab or bevacizumab in combination with 5-fluorouracil/leucovorin/irinotecan (FOLFIRI) or 5-fluorouracil/ leucovorin/oxaliplatin (FOLFOX) between January 2013 and April 2017 from the Flatiron Health electronic health record-derived database of de-identified patient-level data in the United States. Primary tumor location was abstracted from patients' charts. Left-sided primary tumor location (LPTL) was defined as tumors that originated in the splenic flexure, descending colon, sigmoid colon, or rectum; right-sided primary tumor location (RPTL) was defined as tumors that originated from the appendix, cecum, ascending colon, hepatic flexure, or transverse colon. Propensity score matching was used to balance the baseline demographic and clinical characteristics between patients treated with cetuximab and patients treated with bevacizumab. Kaplan-Meier and Cox regression methods were used for survival analyses. RESULTS: = 0.996). The interaction of treatment and primary tumor location was not significant in the Cox regression. CONCLUSION: bevacizumab in combination with 5-fluorouracil-based chemotherapy.