Adjuvant chemotherapy for stage II right-sided and left-sided colon cancer: analysis of SEER-medicare data.

Autor: Weiss JM; Department of Medicine, University of Wisconsin School of Medicine and Public Health (UWSMPH), Madison, WI, USA, jmw@medicine.wisc.edu., Schumacher J, Allen GO, Neuman H, Lange EO, Loconte NK, Greenberg CC, Smith MA
Jazyk: angličtina
Zdroj: Annals of surgical oncology [Ann Surg Oncol] 2014 Jun; Vol. 21 (6), pp. 1781-91. Date of Electronic Publication: 2014 Mar 19.
DOI: 10.1245/s10434-014-3631-8
Abstrakt: Background: Survival benefit from adjuvant chemotherapy is established for stage III colon cancer; however, uncertainty exists for stage II patients. Tumor heterogeneity, specifically microsatellite instability (MSI), which is more common in right-sided cancers, may be the reason for this observation. We examined the relationship between adjuvant chemotherapy and overall 5-year mortality for stage II colon cancer by location (right- vs left-side) as a surrogate for MSI.
Methods: Using Surveillance, Epidemiology, and End Results (SEER)-Medicare data, we identified Medicare beneficiaries from 1992 to 2005 with AJCC stage II (n = 23,578) and III (n = 17,148) primary adenocarcinoma of the colon who underwent surgery for curative intent. Overall 5-year mortality was examined with Kaplan-Meier survival analysis and Cox proportional hazards regression with propensity score weighting.
Results: It was found that 18 % of stage II patients (n = 2941) with right-sided cancer and 22 % (n = 1693) with left-sided cancer received adjuvant chemotherapy. After adjustment, overall 5-year survival benefit from chemotherapy was observed only for stage III patients (right-sided: hazard ratio [HR], 0.64; 95 % CI, 0.59-0.68; p < .001 and left-sided: HR, 0.61; 95 % CI, 0.56-0.68; p < .001). No survival benefit was observed for stage II patients with either right-sided (HR, 0.97; 95 % CI, 0.87-1.09; p = .64) or left-sided cancer (HR, 0.97; 95 % CI, 0.84-1.12; p = .68).
Conclusions: Among Medicare patients with stage II colon cancer, a substantial number receive adjuvant chemotherapy. Adjuvant chemotherapy did not improve overall 5-year survival for either right- or left-sided colon cancers. Our results reinforce existing guidelines and should be considered in treatment algorithms for older adults with stage II colon cancer.
Databáze: MEDLINE
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