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Effect of Age on Survival Benefit of Adjuvant Chemotherapy in Elderly Patients with Stage III Colon Cancer
Author(s) -
Zuckerman Ilene H.,
Rapp Thomas,
Onukwugha Ebere,
Davidoff Amy,
Choti Michael A.,
Gardner James,
Seal Brian,
Mullins C. Daniel
Publication year - 2009
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/j.1532-5415.2009.02355.x
Subject(s) - medicine , hazard ratio , colorectal cancer , confidence interval , cancer , chemotherapy , epidemiology , stage (stratigraphy) , proportional hazards model , retrospective cohort study , cohort , propensity score matching , oncology , surgery , paleontology , biology
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.