Definitive Radiation for Stage I Lung Cancer in a Screened Population: Results From the I-ELCAP

Purpose: The International Early Lung Cancer Action Program is a cohort study to assess the cure rate of participants undergoing annual low-dose computed tomography screening for lung cancer. This study compares the characteristics and outcomes of patients who received a diagnosis of clinical stage I non-small cell lung carcinoma (NSCLC) treated with definitive radiation therapy and surgical resection.

Methods and materials: Patient information was drawn from the International Early Lung Cancer Action Program database from 1992 to 2017. All instances in which treatment was performed for histologically proven stage I NSCLC using definitive radiation therapy and surgery were identified. The home institution determined radiation plans. Patient characteristics and Kaplan-Meier lung cancer-specific (LCS) long-term survival rates were compared for both types of treatment. Follow-up time was calculated from time of diagnosis until death from lung cancer, loss to follow-up, or December 31, 2017, whichever came earlier.

Results: Among 82,628 baseline and 109,250 annual repeat screenings, 853 patients received a diagnosis of clinical stage I NSCLC, of whom 31 (3.6%) were treated by definitive radiation therapy and 702 (82.3%) by surgical resection alone. Radiation therapy prescription information was obtainable for 24 of the 31 patients: The median dose was 54.5 Gy, the median number of fractions was 5, and 17 patients were treated using stereotactic body radiation therapy. LCS survival rates were not significantly different for radiation therapy compared with surgery: 90.0% (95% confidence interval, 84.9%-100.0%) versus 94.8% (95% confidence interval, 93.0%-96.6%) (P = .09). Median follow-up time was 9.7 years for all, but it was shorter for those treated by radiation therapy than for those who underwent surgery (4.3 vs 10.0 years, P < .0001).

Conclusions: The majority of patients identified by computed tomography screening were treated with surgical resection. Despite being older and having more comorbidities, LCS long-term survival rates of patients treated with definitive radiation therapy were not significantly different compared with survival rates of patients treated with surgery alone. Radiation therapy appears to be a viable alternative to surgery for screen-diagnosed patients with lung cancer.