[Radiotherapy for SMARCA4-deficient Pulmonary Neoplasms: Efficacy and Related Parameter Analysis].

Abstract

Background: SMARCA4-deficient pulmonary neoplasms have emerged as a major focus of lung cancer research in recent years. This subtype is characterized by aggressive behavior and poor prognosis. However, radiotherapy-related studies in this population remain scarce, and evidence is lacking regarding the optimal selection of radiotherapy parameters and the sequencing of combination with immunotherapy. The present study aimed to evaluate the efficacy of radiotherapy in these tumors and to explore the prognostic value of radiotherapy parameters.

Methods: Clinical data of 88 patients with SMARCA4-deficient pulmonary neoplasms were retrospectively analyzed. Patients were divided into a radiotherapy group (n=20) and a non-radiotherapy group (n=68). Overall survival (OS) was compared between groups using the Kaplan-Meier method. Subgroup analyses were performed for radiotherapy site, biological equivalent dose (BED), fractionation mode, and the timing of radiotherapy combined with immunotherapy.

Results: The radiotherapy group had a lower proportion of patients aged ≥60 years (25.0% vs 66.2%, P<0.001) and a higher proportion receiving immunotherapy (65.0% vs 33.8%, P=0.013) compared with the non-radiotherapy group. The median OS was not reached in the radiotherapy group, which was significantly superior to that in the non-radiotherapy group (22.9 mon, P=0.048). Among patients receiving radiotherapy, those who also received immunotherapy had a significantly longer median OS than those receiving radiotherapy alone. No statistically significant differences in OS were observed among subgroups stratified by radiotherapy site, BED, fractionation schedule or timing.

Conclusions: Radiotherapy effectively improves OS in SMARCA4-deficient lung tumors, with synergistic potential when combined with immunotherapy. The lack of prognostic impact of radiotherapy parameters supports regimen simplification, while the timing of combined therapy needs refinement. These exploratory results lay a critical foundation for future large‑sample confirmatory studies.