Background/Aim: Adjuvant radiotherapy (RT) for breast cancer can be associated with acute dermatitis (ARD) and pneumonitis (RP). Prevalence and risk factors were characterized. Patients and Methods: This study included 489 breast cancer patients receiving adjuvant RT with conventional fractionation (CF) ± sequential or simultaneous integrated boost, or hypo-fractionation ± sequential boost. RTregimen and 15 characteristics were investigated for grade ≥2 ARD and RP. Results: Prevalence of grade ≥2 ARD and RP was 25.3% and 2.5%, respectively. On univariate analyses, ARD was significantly associated with CF and radiation boost (p<0.0001), age ≤60 years (p=0.008), and systemic treatment (p=0.002). On multivariate analysis, and age (p=0.009) were associated with ARD. Chronic inflammatory disease was significantly associated with RP on univariate (p=0.007) and multivariate (p=0.016) analyses. Conclusion: Risk factors for grade ≥2 ARD and RP were determined that may help identify patients who require closer monitoring during and after RT.Breast cancer is the most common cancer type in females in Western countries (1, 2). Many of these women with nonmetastatic disease receive breast conserving surgery or mastectomy followed by local or loco-regional irradiation (3,4). Adjuvant radiotherapy (RT) may be associated with adverse events including acute radiation dermatitis (ARD) and radiation pneumonitis (RP) (5,6). ARD was reported to have a negative impact on the patients' quality of life, and RP can even be fatal (7, 8). In the literature, the prevalence of clinically relevant grade ≥2 ARD ranges between 3% and 76%, with higher rates in patients treated with conventional fractionation (CF) than in patients receiving hypofractionation (HF) (9-26). ARD usually develops during the second to third week of radiotherapy, becomes more severe during the further RT-course and possibly the first post-RT week, and disappears a few weeks after completion of RT (5). In contrast, RP is considered a subacute effect of RT, which often develops only several weeks or months following RT (6). The prevalence of RP after RT of breast cancer ranges between 0.8% and 19. 6% (6, 10, 27-33). Considering the comparably wide ranges regarding the prevalence of ARD and RP, it becomes obvious that additional studies are required to more precisely define the prevalence of these two RT-related side effects in breast cancer patients. Our present study evaluated the prevalence in a cohort of breast cancer patients irradiated between 2016 and 2019. Moreover, it aimed to determine risk factors for ARD and RP, in order to contribute to early identification of patients at risk who would benefit from closer monitoring of adverse events during and after the RT-course.
Patients and MethodsThe present retrospective study investigated grade ≥2 ARD and grade ≥2 RP in 489 female breast cancer patients treated with adjuvant radiotherapy between 2016 and 2019. The original study protocol and an amendment were approved by the ethics committee of the University of Lü...