Dynamics of Pulmonary Perfusion and Function Following Radical Treatment for Lung Tumors: A Prospective Comparative Study of Surgery, Radiotherapy, and Thermal Ablation.

Background/Objectives: Accurate assessment of pulmonary function is essential before planning radical lung cancer treatment. While spirometry reflects global lung function, perfusion imaging provides detailed information on regional perfusion patterns. This study aimed to characterize the pre-treatment profile of patients and compare the impact of surgical resection, radiotherapy, and thermal ablation on global pulmonary function and regional perfusion using SPECT/CT. Methods: In this prospective study of 68 patients, pre- and post-treatment assessments were conducted using lung perfusion SPECT/CT. While the entire cohort underwent imaging, longitudinal global pulmonary function (spirometry and gas diffusion) was analyzed for 45 patients who completed the three-month follow-up. Quantitative analysis included perfusion percentages and lung volumes, while a semi-quantitative scoring system evaluated the severity of perfusion defects. Results: In the overall cohort, the affected lung perfusion and volume significantly decreased (p = 0.002). Subgroup analysis revealed that the surgical resection group experienced significant reductions in perfusion (from 54.0% to 41.0%, p = 0.002) and volume (p < 0.001) of the affected lung, whereas no statistically significant changes were observed in the thermal ablation and radiotherapy groups (p > 0.05). Notably, 60.3% of patients presented with perfusion defects before treatment. Post-treatment spirometry parameters, particularly FEV1% (threshold 83.5%, AUC = 0.783), served as reliable predictors of persistent perfusion impairment. Conclusions: Radiotherapy and thermal ablation are lung-perfusion-sparing treatments compared to surgical resection. The high prevalence of pre-existing perfusion defects emphasizes the importance of incorporating lung perfusion SPECT/CT into routine pre-treatment evaluation to optimize treatment selection.