Abstract
BACKGROUND: Radiation therapy (RT) is a primary postsurgical treatment for breast cancer; however, it can cause acute radiation dermatitis (ARD), which can severely impair quality of life. The aim of this study was to identify predictive factors associated with moderate to severe ARD. MATERIALS AND METHODS: In this retrospective analysis, we utilized data from Chulabhorn Hospital's Health Information System that was collected between January 2017 and December 2022. A radiation oncology specialist assessed ARD in a cohort of 635 patients using the Radiation Therapy Oncology Group (RTOG) ARD grading scale. The patients were classified into two groups based on the maximum grade recorded: mild (grade < 2) and moderate to severe (grade ≥ 2). Various factors were examined, including demographic characteristics (age, body mass index (BMI), comorbidities) and treatment-related variables (surgical history, adjuvant chemotherapy, hormone therapy, targeted therapy, fractionation, boost treatments, and bolus application). Logistic regression was used to perform the statistical analysis. RESULTS: Among the 635 patients, the average age was 54.2 ± 10.9 years, and 32% were classified as having moderate to severe ARD. Multiple logistic regression analysis identified BMI ≥ 30 kg/m(2) (adjusted odds ratio (AOR) = 2.33; 95% confidence interval (CI) [1.36-3.98]; p-value = 0.002), localized boost treatments (AOR = 2.09; 95% CI [1.08-4.06]; p-value = 0.029), and bolus application (AOR = 2.08; 95% CI [1.02-4.24]; p-value = 0.044) as significant risk factors for moderate to severe ARD. Conversely, hypofractionated RT (AOR = 0.31; 95% CI [0.16-0.57]; p < 0.001) and hormonal therapy (AOR = 0.60; 95% CI [0.42-0.86]; p-value = 0.005) were associated with a decreased risk. However, radiation to both the primary site and regional lymph nodes (AOR = 0.81; 95% CI [0.41-1.59]; p-value = 0.538) and targeted therapy (AOR = 0.72; 95% CI [0.43-1.20]; p-value = 0.210) did not significantly affect the risk of moderate to severe ARD. CONCLUSIONS: We have identified key risk factors for moderate to severe ARD, including obesity and treatment modalities such as localized boost treatments and bolus application. Hormone therapy and hypofractionated RT appear to reduce ARD severity. These findings have implications for the development of treatment plans and the mitigation of the risk of ARD in patients undergoing RT.