Role of surgical resection among chemotherapy-treated patients with colorectal cancer stage IV disease: A survival analysis.

Abstract

3564 Background: Advances in systemic chemotherapy have provided significant survival improvements in patients with stage IV colorectal cancer (CRC). The benefit of surgery to remove the primary tumor among these patients is controversial. The purpose of this study was to analyze CRC-specific survival (CRC-SS) and overall survival (OS) associated with surgical resection of primary tumor among chemotherapy-treated CRC patients with stage IV disease. Methods: 12,239 chemotherapy-treated CRC patients with stage IV disease in the California Cancer Registry between 1989 and 2008 were analyzed. Patients with contraindications to undergo surgery were excluded. Patients were stratified into surgery and no-surgery groups. Estimates of median CRC-SS and OS were generated using the Kaplan-Meier method. Multivariate CRC-SS and OS analyses were performed using Cox proportional-hazard ratios adjusted for age, gender, race/ethnicity, histology, primary tumor site, surgery, and socioeconomic status. Results: Surgical resection of the primary tumor was performed in 76.6% of patients (9,373 of 12,239); partial colectomy was the most frequent type of surgery performed (44.0%). Median age was similar in both surgery and no-surgery groups, 64.0 (range 11-94) vs. 64.0 (range 15-97) years. Proximal/transverse colon was the most likely primary tumor site in the surgery group (45.1%); rectum was the most likely primary tumor site in the no-surgery group (35.6%). Patients undergoing resection had higher median CRC-SS and OS rates, 18 vs. 9 months (P <0.0001) and 17 vs. 8 months (P <0.0001) respectively. In the multivariate model, surgical resection of the primary tumor was associated with a statistically significant improvement in both CRC-SS (HR 0.44; 95% CI 0.42-0.46; P < 0.0001) and OS (HR 0.42; 95% CI 0.40-0.44; P < 0.0001). The benefit was seen in both colon cancer (CRC-SS HR 0.40; 95% CI 0.37-0.43; P <0.0001; OS HR 0.39; 95% CI 0.36-0.41; P < 0.0001) and rectal cancer (CRC-SS HR 0.45; 95% CI 0.41-0.49; P <0.0001; OS HR 0.45; 95% CI 0.41-0.48; P < 0.0001). Conclusions: Surgical resection of primary tumor provided significant improvements in both CRC-SS and OS among stage IV chemotherapy-treated CRC patients.