Introduction
To evaluate the clinical and dosimetric parameters that increase the risk of radiation pneumonitis (RP) in locally advanced non‐small cell lung cancer (NSCLC) patients treated with concomitant chemoradiotherapy of nationwide multicentric data analysis.
Methods
All data of 268 patients who underwent definitive chemoradiotherapy were retrospectively collected from eight institutes participating in this study. Patient, tumor and treatment‐related factors and dosimetric parameters were analyzed for grade ≥2 RP. The toxicity scoring system of The Radiation Therapy Oncology Group used for grading the severity of pneumonitis. A relationship with the risk of RP with potential predictive factors were evaluated by univariate and multivariate analyses. A recursive partition analysis (RPA) was applied to stratify patients according to the risk of developing RP.
Results
There were 90 (33.6%) patients who had grade ≥2 RP. The median time to pneumonitis after treatment was 4 months (range:1‐6 months). In univariate analysis, diabetes mellitus (DM), use of cisplatin/etoposide, total and daily radiotherapy (RT) fraction dose, the planning target volume (PTV) size, mean lung dose, V5, V10 and RT technique were associated with the development of pneumonitis. In multivariate analysis, only DM (P = 0.008) was found to be independent risk factors for RP. According to RPA, the risk of developing RP was highest in patients with DM.
Conclusions
In our study, besides the known dosimetric factors, DM was found to be the most important risk factor causing RP development in multivariate analysis and RPA. The risk is tripled compared to patients without DM.
In this study, we aimed to review the heart and left coronary artery doses over the years in patients who received breast cancer radiotherapy (RT).
Materials and Methods:A total of 436 breast cancer patients of 2 RT centers treated between the years 2010 and 2018 were included. The mean heart doses (HeartDmean-HDM) and left coronary artery mean doses (LDM) were analyzed using nonparametric tests. The conventional RT (CRT) was 50 Gy/2 Gy in 5 weeks, and the hypofractionated RT (HRT) was 40.05 Gy/2.67 Gy in 3 weeks. Boost was applied as 10-16 Gy/2 Gy for CRT and 10 Gy/2.5 Gy for HRT. An equivalent conventional total dose of 2 Gy/fraction (EQD2) was taken into account for HRT.Results: HDM was 107±104 cGy, and LDM was 288±209 cGy for the entire group. HDM was significantly lower in patients with breast-conserving surgery (99±94 cGy) than that in those with mastectomy (128±124 cGy) (p<0.001). Field-in-field intensity-modulated RT technique significantly reduced the doses compared to volumetric applications (104±95 cGy vs 141±38 cGy; p = 0.002). HDM was significantly increased with lymphatic RT (132±58 cGy vs 112±115 cGy; p<0.001). The addition of internal mammary volumes significantly increased HDM (p<0.001). No significant effect of boost was observed (p = 0.96). For both CRT and HRT regimens, HDM values were significantly lower after the year 2014 (right side p<0.001, left side p = 0.01). In the left side CRT, HDM was 1.74 Gy before 2014 and 1.3 Gy after 2014 and 1.0 and 1.19 Gy, respectively, for the right side.
Conclusion:All efforts to reduce the cardiac doses will likely reduce long-term side effects.
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