Effect of Age on Survival Benefit of Adjuvant Chemotherapy in Elderly Patients with Stage III Colon Cancer

• Published in: Journal of the American Geriatrics Society (JAGS) 2009-08, Vol.57 (8), p.1403-1410
• Main Authors: Zuckerman, Ilene H., Rapp, Thomas, Onukwugha, Ebere, Davidoff, Amy, Choti, Michael A., Gardner, James, Seal, Brian, Mullins, C. Daniel
• Format: Article
• Language: English
• Subjects: Age; Age Factors; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Biological and medical sciences; Chemotherapy; Chemotherapy, Adjuvant; Clinical outcomes; Colonic Neoplasms - drug therapy; Colonic Neoplasms - mortality; Colonic Neoplasms - pathology; Colorectal cancer; Effects; elderly; Female; Fluorouracil - administration & dosage; Gastroenterology. Liver. Pancreas. Abdomen; General aspects; Humans; Leucovorin - administration & dosage; Logistic Models; Male; Medical sciences; Medicare; Miscellaneous; Neoplasm Staging; Older people; Proportional Hazards Models; Public health. Hygiene; Public health. Hygiene-occupational medicine; Retrospective Studies; SEER; SEER Program; Stage III colon cancer; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; survival; Survival Analysis; Treatment Outcome; Tumors; United States
• ISSN: 0002-8614; 1532-5415
• DOI: 10.1111/j.1532-5415.2009.02355.x

OBJECTIVES: To estimate the modifying effect of age on the survival benefit associated with adjuvant chemotherapy receipt in elderly patients with a diagnosis of Stage III colon cancer. DESIGN: Observational, retrospective cohort study using two samples: an overall sample of 7,182 patients to provide externally valid analyses and a propensity score–matched sample of 3,016 patients to provide more internally valid analyses by reducing the presence of treatment endogeneity. An interval‐censored survival model with a complementary log‐log link was used. Hazard ratios and 95% confidence intervals were obtained for all regressions. SETTINGS: Data from the National Cancer Institute's Surveillance, Epidemiology and End Results database and the linked Medicare enrollment and claims database were used. PARTICIPANTS: Selected patients were aged 66 and older and had a diagnosis of Stage III colon cancer. Patients were followed from surgery to time of death or censorship. MEASUREMENTS: The outcome was colon cancer–specific death during the follow‐up period. Receipt of adjuvant chemotherapy was measured according to the presence of a claim for 5‐fluorouracil or leucovorin within 6 months after surgery. RESULTS: All elderly patients had a significant survival benefit associated with adjuvant chemotherapy receipt, although the survival benefit of adjuvant chemotherapy was not uniform across all age groups. CONCLUSION: These findings have important clinical and policy implications for the risk–benefit calculation induced by treatment in older patients with Stage III colon cancer. The results suggest that there is a benefit from chemotherapy, but the benefit is lower with older age.