Radiotherapy for Ductal Carcinoma In Situ: Toxicity, Quality of Life, and Decisional Regret at a Tertiary Cancer...

Purpose: Adjuvant radiotherapy (RT) for ductal carcinoma in situ (DCIS) remains a widely discussed topic. While it has been shown to significantly reduce recurrence rates, it does not improve overall survival (OS) and may therefore lead to overtreatment in some cases. This study aimed to assess patient acceptance, quality of life (QoL), and decisional regret (DR) in relation to late adverse effects. Methods: Clinical data from patients who underwent RT for DCIS between 2008 and 2020 were retrospectively collected, while follow-up questionnaires evaluated QoL and DR. High-risk DCIS was defined as tumor size ≥ 2.5 cm, poor differentiation (G3), age ≤ 50, and symptomatic diagnosis. Low-risk disease was defined as tumor size < 2 cm, G1/G2, age > 50, and mammographic diagnosis. Patients who did not meet all criteria for either category were classified as intermediate risk, therefore reflecting everyday work and clinical practice. Questionnaire data were analyzed using both scale-level and item-level approaches and Ipsilateral breast recurrence-free survival (IBRFS) rates were calculated using the Kaplan-Meier method. Results: Among 307 cases offered RT, only 24 declined, indicating high treatment acceptance; an additional 20 cases lacked sufficient documentation, did not receive RT at our center despite acceptance, or discontinued RT prematurely. During the study period, late toxicities occurred at acceptable frequencies: fibrosis in 6.1%, hyperpigmentation in 6.8%, telangiectasia in 8%, and edema in 1.5% of cases with excellent control rates of 90.0%. The response rate to the EORTC QLQ-C30 and Ottawa Decisional Regret Scale (DRS) was 35.4%, of whom 70 cases belonged to the intermediate-risk group. These respondents reported high QoL and low levels of DR. Conclusions: RT for intermediate grade DCIS is accepted and tolerated well, and neither late adverse effects nor QoL outcomes were associated with DR. These findings support recommending RT in this borderline-indication group.