The Association of Tumor Laterality and Survival After Cytoreduction for Colorectal Carcinomatosis

Background: Primary tumor location has emerged as an important surrogate for tumor biology in metastatic colorectal cancer treated with systemic chemotherapy. It is unclear if primary tumor location is associated with survival after cytoreductive surgery (CRS) with or without heated intraperitoneal chemotherapy (HIPEC) for colorectal carcinomatosis. Methods: Study of a contemporary cohort merged data from the California Cancer Registry, 2004-2012, and the Office of Statewide Health Planning and Development inpatient database. For patients undergoing CRS/HIPEC, clinicopathologic variables, treatment characteristics, and survival were compared by right versus left colon primary site. Survival was analyzed by Cox proportional hazards. Results: Of 272 patients identified, 128 (47.1%) had right-sided tumors. Left- and right-sided cohorts had similar patient, tumor, and treatment factors. Patients with left-sided primary tumors had significantly prolonged overall survival (mean 34 versus 15.5 mo, P = 0.0010). Factors independently associated with decreased overall survival included age >80 (HR 7.0, P < 0.0001), advanced T4 stage (HR 3.6, P = 0.0031), and positive lymph nodes (HR 2.2, P = 0.0004). Metachronous peritoneal involvement (HR 0.38, P < 0.0001) and left-sided primary tumors (HR 0.72, P = 0.041) were independently associated with improved overall survival. Conclusions: This study identifies location of primary tumor as an important determinant of long-term survival after CRS/HIPEC. Patients with left-sided tumors have a more favorable prognosis.