Surgical Resection of the Primary Tumor in Stage IV Colorectal Cancer Without Metastasectomy Is Associated With Improved Overall Survival Compared With Chemotherapy/Radiation Therapy Alone

BACKGROUND: Controversy exists over whether resection of the primary tumor in stage IV colorectal cancer with inoperable metastases improves patient outcomes. OBJECTIVE: The purpose of this study was to evaluate whether resection of the primary tumor without metastasectomy in patients with stage IV colorectal cancer is associated with improved overall survival compared with patients undergoing chemotherapy and/or radiation therapy alone. DESIGN: This was a retrospective review of a multi-institutional dataset. SETTINGS: This study was conducted in all participating commission on cancer (CoC)-accredited facilities. PATIENTS: The 2003-2006 National Cancer Data Base was reviewed to identify patients with stage IV adenocarcinoma of the colon or rectum who underwent palliative treatment without curative intent, either in the form of surgical resection of the primary tumor without metastasectomy consisting of a colectomy or rectal resection with or without chemotherapy and/or radiation or chemotherapy and/or radiation alone. MAIN OUTCOME MEASURES: Groups were compared for baseline characteristics. Overall survival was compared using Kaplan-Meier analysis before and after propensity matching with a 1:1 nearest-neighbor algorithm. RESULTS: Of the 1446 patients included in the analysis, 231 (16%) underwent surgical resection of the primary tumor without metastasectomy. Surgical resection was associated with a significant survival benefit on unadjusted analysis (median survival, 9.2 vs. 7.6 months; p < 0.01). After propensity matching to adjust for nonrandom treatment selection, surgical resection continued to be associated with a significant survival benefit (median survival, 9.2 vs. 7.3 months; p < 0.01). LIMITATIONS: This study was limited by the potential for selection bias regarding which patients received surgical resection. There was also a lack of data regarding the indication for operation, specifically whether a patient was symptomatic or asymptomatic before resection. The inability to account for tumor size or grade among patients who did not receive surgical resection was another limitation. CONCLUSIONS: Surgical resection of the primary tumor without metastasectomy in patients with metastatic colorectal cancer is associated with improved survival as compared with chemotherapy/radiation therapy alone. Additional research is necessary to determine which patients may benefit from this intervention.