Effect of age on the efficacy of adjuvant chemotherapy for resected non-small cell lung cancer

BACKGROUND Adjuvant chemotherapy after surgical resection improves outcomes for patients with early-stage non-small cell lung cancer (NSCLC). To the authors' knowledge, there are no published prospective trials to date of adjuvant chemotherapy after surgical resection administered exclusively in older patients. In the current study, the authors sought to evaluate the efficacy of adjuvant chemotherapy in older patients in a Veterans Health Administration cohort. METHODS Patients who underwent surgical resection for American Joint Committee on Cancer stages IB to III NSCLC between 2001 and 2011 were analyzed. Data regarding patient demographics and comorbidities, tumor characteristics, and primary treatment were collected. Patients were divided into 2 groups based on age at diagnosis: those aged <70 years and those aged ≥70 years. The primary exposure was use of adjuvant chemotherapy. A Cox proportional hazards model was used to estimate the significance of patient characteristics. Survival curves were estimated using the Kaplan-Meier method and group comparisons were performed using the log-rank test. RESULTS The analysis included 7593 patients who underwent surgical resection for stage IB to stage III NSCLC. Among these, 2897 patients (38%) were aged ≥70 years. The percentage of older patients who received adjuvant chemotherapy was approximately one-half that of younger patients who did so (15.3% vs 31.6%; P<.0001). Carboplatin-based doublets were used most often in all patients (64.6%). Both younger patients (hazard ratio, 0.79; 95% confidence interval, 0.72-0.86) and older patients (hazard ratio, 0.81; 95% confidence interval, 0.71-0.92) were found to have a lower risk of death with receipt of adjuvant chemotherapy. CONCLUSIONS Older patients derive a similar magnitude of benefit from adjuvant chemotherapy as younger patients and therefore adjuvant chemotherapy should not be withheld based on age alone. Cancer 2015;121:2578-2585.