Chapter 3
Comparative Effectiveness of Fluoropyrimidine-Based Chemotherapy in Elderly Medicare Patients Diagnosed with Metastatic Colorectal Cancer
by Sacha Satram-Hoang, Carolina Reyes, Edward McKenna and Khang Q. Hoang
Abstract
Background: Treatment advances have led to improved outcomes in clinical trials of patients with metastatic colorectal cancer (mCRC). Less is known about treatment outcomes for patients in real-world settings. This study evaluated treatment patterns, overall survival, and frequency of complications requiring medical resource utilization in an older, demographically diverse patient population undergoing treatment for mCRC in routine medical practice. Methods: Using the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we conducted a retrospective cohort analysis of 4,250 first primary mCRC patients diagnosed from January 1, 2000 to December 31, 2007. Patients were ≥ 66 years, enrolled in Medicare Parts A and B, received treatment with any oral or infused chemotherapy after diagnosis, and survived at least 60 days following the date of first-line chemotherapy initiation. Statistical comparisons were made between 5-FU/LV (fluorouracil and leucovorin) vs. CAP (capecitabine) and FOLFOX (5-FU/LV plus oxaliplatin) vs. CAPOX (CAP plus oxaliplatin). Differences between treatment groups were evaluated with chi-square tests for categorical variables and analysis of variance or t-test for continuous variables. Multivariate Cox proportional hazards regression with backward elimination, and propensity score-weighted Cox proportional hazards regression estimated the relative risk of death. Date of last follow-up was December 31, 2009. Results: There were 2213 patients who received 5-FU/LV, 1298 received FOLFOX, 617 were administered CAP, and 122 received CAPOX who met the study inclusion criteria. Compared to 5-FU/LV, patients treated with CAP were older (mean age 78 vs. 76; P < 0.0001) and more likely female (61% vs. 54%; P = 0.0017), while patients receiving CAPOX and FOLFOX were similar in age (mean age 74 vs. 73; P =0.0924). Complications requiring medical resource utilization within 180 days following initiation of therapy were significantly higher among patients administered 5-FU/LV (54%) vs. CAP (17%; P < 0.0001) and FOLFOX (75%) vs. CAPOX (57%; P < 0.0001). The multivariate Cox proportional hazards regression revealed no significant differences in mortality between 5-FU/LV and CAP (HR= 0.94; 95% CI: 0.89-1.23) and between FOLFOX and CAPOX (HR=0.88; 95% CI: 0.56-1.37). The propensity score-weighted Cox regression analyses confirmed these findings. Conclusions: Overall survival for elderly mCRC patients who were treated in routine medical oncology practice was comparable between CAP and 5-FU/LV and between CAPOX and FOLFOX with fewer complications requiring medical resource utilization associated with CAP and CAPOX. These data provide real-world confirmation of clinical trial data in younger patients and imply that age should not discourage the use of guideline-recommended therapies for mCRC.
Author Details
Department of Epidemiology, Q.D. Research Inc., USA
Health Economics & Outcomes Research, Genentech Inc., USA; Department of Clinical Pharmacy, University of California, San Francisco, USA
U.S. Medical Affairs, Genentech Inc., USA
Medical Affairs, Q.D. Research Inc., USA