Abstract
PURPOSE: To evaluate the safety and efficacy of Helical Tomotherapy stereotactic body radiotherapy (HT-SBRT) in treating multiple primary lung cancers (MPLCs) and second primary lung cancer (SPLC). METHODS: From January 2010 to September 2023, 106 MPLCs and SPLC (T1-3N0M0) underwent HT-SBRT. The cumulative incidence for local recurrence (LR) was calculated using the competing risk approach and compared using Gray's test. Cancer-specific survival (CSS) and progression-free survival (PFS) were assessed using Kaplan-Meier analysis and log-rank tests. RESULTS: After adjusting for competing risks, the LR rates for all lesions (n = 150) was 15.3%, with 2- and 4-year rates of 7.5% and 11.4%. For second primary lung nodules post-surgery, the cumulative incidence of LR was 16.1%, with 2- and 4-year rates of 6.9% and 8.7%. In MPLCs treated with HT-SBRT, the cumulative incidence of LR was 14.3%, with 2- and 4-year rates of 8.2% and 14.3%. In patients with MPLCs treated with HT-SBRT (n = 27), the CSS rates at 2, 4, and 10 years were 90.5%, 78.6%, and 53.6%, respectively, and the PFS rates were 59.5%, 32.8%, and 24.6%. In patients with SPLC who received HT-SBRT after surgery (n = 79), the CSS rates at 2, 4, and 10 years were 90.9%, 81.7%, and 61.0%, respectively, while the PFS rates were 75.4%, 64.4%, and 58.5%. Additionally, 0.9% of patients experienced grade 3 acute radiation pneumonitis, and no severe (grade 4-5) toxicities were reported. CONCLUSIONS: HT-SBRT may be a safe and effective treatment for MPLCs and SPLC, though prospective studies are needed to confirm its efficacy.