Mortality by Stage for Right- Versus Left-Sided Colon Cancer: Analysis of Surveillance, Epidemiology, and End Results–Medicare Data

• Published in: Journal of clinical oncology Vol. 29; no. 33; pp. 4401 - 4409
• Main Authors: WEISS, Jennifer M, PFAU, Patrick R, O'CONNOR, Erin S, KING, Jonathan, LOCONTE, Noelle, KENNEDY, Gregory, SMITH, Maureen A
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Society of Clinical Oncology 20.11.2011
• Subjects: Aged; Aged, 80 and over; Biological and medical sciences; Colonic Neoplasms - mortality; Colonic Neoplasms - pathology; Female; Gastroenterology. Liver. Pancreas. Abdomen; Humans; Male; Medical sciences; Medicare; Neoplasm Staging; Original Reports; SEER Program; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Tumors; United States; United States; Health insurance; Right colon; Mortality; Malignant tumor; Epidemiology; Colonic disease; Clinical stage; Colon cancer; Cancerology; Surveillance; Digestive diseases; Intestinal disease; Left colon; Comparative study; Cancer
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/JCO.2011.36.4414

Recent studies have reported increased mortality for right-sided colon cancers but had limited adjustment for patient characteristics and conflicting results by stage. We examined the relationship between colon cancer location (right- v left-side) and 5-year mortality by stage. We identified Medicare beneficiaries from 1992 to 2005 with American Joint Commission on Cancer stages I to III primary adenocarcinoma of the colon who underwent surgery for curative intent through Surveillance, Epidemiology, and End Results (SEER) -Medicare data. Adjusted hazard ratios (HRs) and 95% CIs for predictors of all-cause 5-year mortality were obtained by using Cox proportional hazards regression. Of 53,801 patients, 67% had right-sided colon cancer. Patients with right-sided cancer were more likely to be older, to be women, to be diagnosed with a more advanced stage, and to have more poorly differentiated tumors. Adjusted Cox regression showed no significant difference in mortality between right- and left-sided cancers for all stages combined (HR, 1.01; 95% CI, 0.98 to 1.04; P = .598) or for stage I cancers (HR, 0.95; 95% CI, 0.88 to 1.03; P = .211). Stage II right-sided cancers had lower mortality than left-sided cancers (HR, 0.92; 95% CI, 0.87 to 0.97; P = .001), and stage III right-sided cancers had higher mortality (HR, 1.12; 95% CI, 1.06 to 1.18; P < .001). When analysis was adjusted for multiple patient, disease, comorbidity, and treatment variables, no overall difference in 5-year mortality was seen between right- and left-sided colon cancers. However, within stage II disease, right-sided cancers had lower mortality; within stage III, right-sided cancers had higher mortality.