Nationwide trends in radiotherapy use among older patients with early-stage non-small cell lung cancer in Japan, 2013-2022.

This study examined trends in radiotherapy use among older patients with early-stage non-small cell lung cancer (NSCLC) in Japan. Using hospital-based cancer registry data (2013–2022), we analyzed 295,662 patients aged ≥ 65 years with epithelial lung tumors (clinical Tis–T2N0M0), excluding those with poorly differentiated endocrine carcinoma or missing treatment data. Overall, 80% underwent surgery, 11% received radiotherapy, and 9% received other management. Radiotherapy use increased from 10.5% in 2013 to 12.8% in 2022 (age- and sex-standardized increase of + 1.2% points). Logistic regression showed increased odds of radiotherapy use in the later period across subgroups according to age, sex, clinical T category, and facility volume, except among patients aged 75–84 years and those treated at high-volume facilities. From 2013 to 2022, radiotherapy use changed by + 1.7, + 0.2, and + 4.5% points among patients aged 65–74, 75–84, and ≥ 85 years, reaching 6.2%, 14.8%, and 35.5%, respectively. Surgery use changed by − 2.1, + 1.3, and − 3.2% points, with values of 89.6%, 76.3%, and 32.8%, respectively. Radiotherapy use increased only modestly, with variation across age groups. Over 30% of patients aged ≥ 85 years underwent surgery, indicating the need to clarify the roles of surgery and radiotherapy in this population.