Abstract
BackgroundThe distinction between right-sided and left-sided colon cancer has recently received considerable attention due to differences regarding underlying genetic mutations. There is an ongoing debate if right- versus left-sided tumor location itself represents an independent prognostic factor. We aimed to investigate this question by using propensity score matching.MethodsPatients with resected, stage I - III colon cancer were identified from the Surveillance, Epidemiology, and End Results (SEER) database (2004–2012). Both univariable and multivariable Cox regression as well as propensity score matching were used.ResultsOverall, 91,416 patients (51,937 [56.8 %] with right-sided, 39,479 [43.2 %] with left-sided colon cancer; median follow-up 38 months) were eligible. In univariable analysis, patients with right-sided cancer had worse overall (hazard ratio [HR] = 1.32, 95 % CI:1.29–1.36, P < 0.001) and cancer-specific survival (HR = 1.26, 95 % CI:1.21–1.30, P < 0.001) compared to patients with left-sided cancer. After propensity score matching, the prognosis of right-sided carcinomas was better regarding overall (HR = 0.92, 95 % CI: 0.89 − 0.94, P < 0.001) and cancer-specific survival (HR = 0.90, 95 % CI:0.87 − 0.93, P < 0.001). In stage I and II, the prognosis of right-sided cancer was better for overall (HR = 0.89, 95 % CI:0.84–0.94 and HR = 0.85, 95 % CI:0.81–0.89) and cancer-specific survival (HR = 0.71, 95 % CI:0.64 − 0.79 and HR = 0.75, 95 % CI:0.70–0.80). Right- and left-sided colon cancer had a similar prognosis for stage III (overall: HR = 0.99, 95 % CI:0.95–1.03 and cancer-specific: HR = 1.04, 95 % CI:0.99–1.09).ConclusionsThis population-based analysis on stage I - III colon cancer provides evidence that the prognosis of localized right-sided colon cancer is better compared to left-sided colon cancer. This questions the paradigm from previous research claiming a worse survival in right-sided colon cancer patients.
Highlights
The distinction between right-sided and left-sided colon cancer has recently received considerable attention due to differences regarding underlying genetic mutations
Primary cancer site and histology were coded according to criteria in the third edition of the International Classification of Diseases for Oncology (ICD-O-3) and used to identify 246,390 patients with colon cancer diagnosed between 2004 and 2012 [22]
Patients with cancer of the cecum and ascending colon were accounted for right-sided colon cancer and patients with cancer of the descending or sigmoid colon were accounted for left-sided colon cancer
Summary
The distinction between right-sided and left-sided colon cancer has recently received considerable attention due to differences regarding underlying genetic mutations. The majority of studies demonstrated a poorer survival in right-sided compared to left-sided colon cancer [14,15,16,17,18]. In contrast to those data, Weiss et al [19] found no overall difference in 5-year mortality between right- and left-sided colon cancer after adjusting for various variables. The objective of the present population analysis of 91,416 colon cancer patients from the Surveillance, Epidemiology, and End Results (SEER) Program was to compare overall and cancer-specific survival between two large, virtually identical groups of patients with right- and left-sided colon cancer using propensity-score matching
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