Primary tumor location and survival in general population with metastatic colorectal cancer (mCRC).

674Background: Recent evidence from clinical trials suggests that location of the primary tumor in patients with mCRC correlates with differential outcomes and patients with tumors originating in the right side of colon have inferior survival. This large population-based cohort study using individual patient data was performed to confirm this findings in general population with mCRC. Methods: A cohort of 1947 patients who were diagnosed with synchronous mCRC from 1992-2010 was studied. Ascending and transverse colon cancers were defined as right-sided tumors (RT) and remainder tumors were define as left-sided tumors (LT). Cox proportional multivariate analyses were done to determine prognostic significance of primary tumor location and to adjust other prognostic variables including age, Charlson comorbid index (CCI) and WHO performance status (PS) in patients treated with chemotherapy. Results: Median age was 70 years (IQR: 60-78) and M:F was 1.3:1. Mean CCI was 9.7±1.4 and 29% had WHO PS of > 1. 770 (39%...