Recent trends in use of adjuvant chemotherapy in elderly stage II- III non-small cell lung cancer

Background: Although randomized trials demonstrated survival benefit of adjuvant chemotherapy, previous reports have suggested that its use in elderly populations for early stage non-small cell lung cancer (NSCLC) was infrequent. The current status of adjuvant chemotherapy in this population is unknown. Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database, we examined the incidence of chemotherapy in resected stage II-III NSCLC between 2004 and 2015. Staging was determined according to the American Joint Committee on Cancer (AJCC) 6th version. Cases were grouped by age (20-69, 70-79, and 80+). Trends in use of chemotherapy by age group were assessed by univariate and multivariate analyses. Results: A total of 35,009 cases were selected as surgically resected stage II-III NSCLC. Use of chemotherapy was 66.9%, 48.2%, 25.0% in age 20-69, 70-79, 80+, respectively. Multivariate analysis demonstrated that younger age [20-69] and recent year [2010-2015] of diagnosis were associated with increased use of chemotherapy. Chemotherapy use increased from 2004 to 2015 by 11.0%, 18.3%, and 11.3% in age 20-69, 70-79, 80+, respectively. In the age 70-79 group, increased use of chemotherapy was greater in stage II (24.3%) than stage III (14.1%). Five-year overall survival in age 70-79 group mildly increased by 7.6% from 2004 to 2011. Conclusions: This study suggests that use of adjuvant chemotherapy in the elderly population increased primarily in age 70-79. Few patients in the 80+ age group received adjuvant chemotherapy even in recent years.