Ductal Carcinoma In Situ of the Breast: An Analysis of 12 Years of Experience From a Tertiary Center.

Background Ductal carcinoma in situ (DCIS) is a non-invasive breast malignancy that accounts for approximately one-fifth of new breast cancer diagnoses in developed countries. While not life-threatening, DCIS is a potential precursor to invasive carcinoma, and optimal management remains a matter of debate. Adjuvant radiotherapy after breast-conserving surgery reduces the risk of local recurrence, and hypofractionated regimens have emerged as an effective and convenient alternative to conventional fractionation. This study aimed to compare acute and late toxicity profiles between hypofractionated and conventional radiotherapy in DCIS patients, with a particular focus on the impact of boost administration. Methodology This retrospective study included 97 female patients with histologically confirmed DCIS treated between January 2013 and January 2025. Patients with invasive components, prior malignancy, or incomplete data were excluded. Radiotherapy was delivered using three-dimensional conformal radiotherapy (n = 43) or intensity-modulated radiotherapy (n = 54), with conventional fractionation (50 Gy/25 fractions, used in 30.9% (30 patients)) or hypofractionated regimens (40-42.6 Gy/15-16 fractions, used in 69.1% (67 patients)). A sequential boost of 10 Gy was applied in high-risk cases. Data were analyzed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA), with significance set at p-values <0.05. Results A total of 97 DCIS patients received adjuvant radiotherapy (mean age: 51 years). Hypofractionated radiotherapy was used in 69.1% (67 patients), and conventional fractionation in 30.9% (30 patients). Acute toxicity occurred in 60.8% (59 patients), while late toxicity was rare (8.2% (8 patients)) and similar across groups. Boost administration was associated with increased acute toxicity in the hypofractionated group (p = 0.044) but not in the conventional group. Only one local recurrence was observed during follow-up. Conclusions Our findings confirm that both hypofractionated and conventional radiotherapy provide excellent local control and acceptable toxicity in DCIS patients, with boost administration significantly increasing acute toxicity in hypofractionated regimens. Despite these differences, long-term outcomes remain favorable, supporting the role of individualized risk-adapted radiotherapy strategies in DCIS management.