Songphol Malakorn1, Akira Ouchi2, Chung-Yuan Hu3, Lakhbir Sandhu3, Arvind Dasari4, Yi-Qian Nancy You3, E Scott Kopetz4, Lee M Ellis3, George J Chang5. 1. Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX; Department of Colorectal Surgery, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. 2. Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX; Department of Gastroenterological Surgery, Aichi Cancer Center Hospital, Aichi, Japan. 3. Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX. 4. Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX. 5. Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX; Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, TX. Electronic address: gchang@mdanderson.org.
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.
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.