Background/Objectives: Despite advancements in treatment for patients with unresectable locally advanced non-small cell lung cancer (LA-NSCLC), overall survival (OS) remains poor. The specific effects of varying heart and lung doses on OS in LA-NSCLC patients have not been thoroughly investigated, especially their combined impact on survival. This study aimed to examine the impact on OS of both individual and combined heart and lung doses in patients with LA-NSCLC treated with radiotherapy over a three-year follow-up period. Methods: A total of 120 patients who received definitive radiotherapy for LA-NSCLC (stage III, 92.5%) from January 2015 to January 2020 were retrospectively reviewed. The endpoint in this study was OS. Each patient was followed for a fixed period of three years. Results: Univariate Cox regression analysis showed that OS was significantly related to mean heart dose (MHD, hazard ratio [HR], 3.4 [1.8–6.3]; p < 0.001), pericardium V40 (HR, 3.2 [1.7–6.0]; p < 0.001), and total lung V20 (HR, 2.6 [1.4–5.0]; p = 0.003), and these were independent predictors for worse OS in multivariate analysis. Kaplan–Meier curve analysis with log-rank tests revealed that survival was significantly worse in patients with higher MHD (p < 0.001), pericardium V40 (p < 0.001), and total lung V20 (p = 0.002). Combining MHD and total lung V20, and pericardium V40 and total lung V20 provided enhanced risk stratification for OS (p < 0.001 for both combinations). Conclusions: The combination of heart and lung doses provided enhanced and more detailed risk stratification in prediction of OS for a fixed period of three years in LA-NSCLC patients treated with radiotherapy.

Background: This study aimed to investigate preoperative spirometry and BMI as early predictors of the mean heart and lung dose (MHD, MLD) in deep inspiration breath-hold (DIBH) radiotherapy. Methods: Left-sided breast cancer patients underwent breast-conserving surgery followed by DIBH radiotherapy enrolled. Patients who were not available for preoperative spirometry were excluded. One hundred eligible patients were performed free-breathing (FB-) CT and DIBH-CT for plan comparison. We completed the correlative and multivariate analysis to develop the linear regression models for dose prediction. The residuals were calculated to explore the unpreferable subgroups and compare the prediction accuracy. Results: Among the parameters, vital capacity (VC) and BMI showed the strongest negative correlation with MHD (r = − 0.33) and MLD (r = − 0.34), respectively. They were also significant in multivariate analysis (P < 0.001). Elderly and less VC were independent predictors of increasing absolute residuals (AR). The VC model showed no significant difference in AR compared to the model using the CT parameter of lung volume in FB (LV-FB): median AR of the LV-FB model vs. the VC model was 0.12 vs. 0.11 Gy (P = 0.79). On the other hand, the median AR of the MLD model was 0.38 Gy, showing no specific subgroups of larger AR. Conclusion: Preoperative spirometry and BMI are significant predictors of MHD and MLD, respectively. Although elderly and low-VC patients may have larger predictive variations, spirometry might be a substitute for LV-FB as a predictor of MHD.

Although the effects of varying heart doses on overall survival (OS) in curative thoracic radiotherapy have been investigated, their impact in palliative settings remains underexplored. This study aimed to examine the impact of heart dose on OS in patients with bone metastases treated with palliative radiotherapy over a three-year follow-up period. This study included 303 patients who underwent palliative radiotherapy for bone metastases between 2013 and 2022. The primary endpoint was OS, which was evaluated over a fixed three-year follow-up period. To adjust for baseline confounders between patients with and without mean heart dose (MHD) ≥5Gy, we performed 1:1 propensity score matching (PSM) using the following variables: performance status (PS); primary tumor type; number of bone metastases; number of distant metastases (visceral organs, non-regional lymph nodes, and serosal surfaces such as the pleura and peritoneum). A total of 108 of 303 patients were included after PSM, with 54 patients each in the groups with and without MHD ≥5 Gy. After matching, the baseline characteristics used as matching variables were well balanced, with no significant differences between the groups according to the chi-square test. Kaplan-Meier analysis demonstrated significantly poorer OS in patients with MHD ≥5 Gy than in those without (p=0.016); annualized event rates for OS were 30.2% and 21.6% in patients with and without MHD ≥5 Gy, respectively. In propensity score-matched patients receiving palliative, but not curative, radiotherapy, higher MHD was significantly associated with poorer OS over a three-year follow-up period. Furthermore, in the palliative cohort, the MHD level associated with OS may be lower than that in the curative setting.