Tumor Sidedness, Recurrence, and Survival After Curative Resection of Localized Colon Cancer.

ABSTRACT

BACKGROUND: Right-sided primary tumor location is associated with worse prognosis in metastatic colon cancer, but the effect of sidedness on recurrence and prognosis for non-metastatic disease is less understood. The purpose of this study was to examine the relationship between sidedness, recurrence, and survival among patients with localized colon cancer. PATIENTS AND METHODS: Consecutive patients who underwent curative resection of colon cancer (2006-2013) were identified from a prospective database and retrospectively analyzed. Risk for recurrence, overall survival, and survival after recurrence (SAR) were compared between left- and right-sided tumors using the log-rank test, and multivariable Cox proportional hazards regression. RESULTS: We evaluated 673 patients (347 right-sided). There was no difference in overall recurrence rates (adjusted hazard ratio [HR], 0.92; 95% confidence interval [CI], 0.54-1.55; P = .75) or overall survival (HR, 1.22; 95% CI, 0.75-1.97; P = .42) between right- and left-sided primary tumors. However, right-sided tumors were more likely to develop multi-focal and poor prognostic site recurrence (P = .04). Among the 71 patients who developed recurrence, those with right-sided tumors had significantly lower SAR (HR, 3.88; 95% CI, 1.42-10.62; P = .008). CONCLUSIONS: Among patients with colon cancer who underwent curative resection, tumor sidedness was not associated with recurrence risk. However, among patients who developed recurrence, right-sidedness was associated with unique recurrence patterns and inferior SAR. For patients presenting with localized disease, treatment stratification should not be based on tumor sidedness alone.