Implementation of Locoregional Adjuvant Radiotherapy for Breast Cancer in a Rural Healthcare Region: Toxicity Outcomes in the Initial Cohort

Background/Aim: The aim of this study was to analyze the toxicity of locoregional adjuvant breast cancer radiotherapy after implementation of this service in a rural healthcare region with long travel distance. Patients and Methods: This was a retrospective single-institution analysis of 87 consecutive female patients (the initial cohort), managed with conventionally fractionated 3-D conformal radiotherapy with or without boost, including both post mastectomy and breast conservation scenarios. Treatment was administered in line with comprehensive national guidelines. Intensity-modulated techniques were not utilized. Results: The median follow-up time was 4 years. None of the patients developed any grade IV side-effects. According to Radiation Therapy Oncology Group criteria, acute grade 2b or 3 skin toxicity was observed in 16%. In addition, 35% developed acute grade 2a skin reactions. A trend was observed regarding grade 2-3 skin toxicities and administration of a boost (p=0.058). There was a significant association between the clinical target volume of the breast and grade 2-3 skin reactions in women who had breast-conserving surgery (p=0.016). Five patients (6%) developed grade 1 pneumonitis, unrelated to dosimetric or other baseline parameters. Conclusion: The toxicity profile after a median follow-up of 4 years was in accordance with published data. Recently, intensity-modulated techniques have been implemented at the study center, which may reduce radiotherapy toxicity in patients with large clinical target volume due to better dose homogeneity.