Evaluating the impact of cardiac substructure dosimetric parameters on survival in lung cancer patients undergoing postoperative radiotherapy.

Abstract

Purpose: The association of cardiac dosimetric parameters with survival in lung cancer patients is well established. However, most research has concentrated on patients undergoing definitive treatment. This study aims to investigate the relationship between cardiac dosimetric parameters and survival in patients receiving postoperative radiotherapy (PORT).

Methods: Sixty patients who received PORT between 2011 and 2021 were retrospectively evaluated. The substructures of the heart were delineated on the simulation computed tomography scans of the patients. Univariate and multivariate Cox regression analyses were conducted to investigate the correlation between dosimetric parameters and overall survival. The Statistical Package for the Social Sciences (SPSS) version 23.0 (IBM Corp., Armonk, NY, USA) was utilized for statistical analyses.

Results: Right atrium (RA) maximum dose (Dmax) was the only variable that was significantly associated with a shorter OS. Further receiver operating characteristic (ROC) analysis revealed that the optimum cut-off value for RA Dmax was 43.6 Gy, with a sensitivity of 69% and a specificity of 62%. In addition, inclusion of the upper right paratracheal (2R), lower right paratracheal (4R), left pulmonary ligament (9L), and right hilus (10R) lymphatic stations in the treatment field led to an increase in RA Dmax.

Conclusion: The results of this retrospective study show that RA Dmax appears to have an impact on overall survival in patients undergoing PORT. Limiting the RA Dmax dose to below 43.6 Gy and avoiding elective nodal irradiation might potentially enhance survival in this patient cohort.