We report the results of a prospective trial investigating the use of accelerated, hypofractionated whole-breast radiation therapy after breast-conservation surgery for ductal carcinoma in situ (DCIS).

A total of 59 patients with a median age of 54 years (range, 36-78 years) completed a phase I/II study of hypofractionated radiation therapy for treatment of DCIS. Eligibility criteria included patients with mammographically detected DCIS, status after segmental mastectomy with negative margins, and no residual calcifications. All patients were treated with external-beam radiation therapy without a boost, over 3 weeks, to a total dose of 42 Gy to the entire breast (2.8 Gy per fraction in 15 fractions). To optimally spare heart and lung, 34 of the 59 patients (57%) were treated in the prone position. Twenty-nine of 59 patients (49%) received adjuvant hormonal therapy.

Overall, radiation therapy was well tolerated, with modest acute toxicity limited to grade 1 radiation dermatitis (76%), breast edema (17%), and fatigue (12%). With a median follow-up of 36 months, late toxicities included grade 1 hyperpigmentation changes (85%), induration (66%), asymmetry (64%), and breast fibrosis (17%), with 3 cases of grade 2 fibrosis and 1 case of grade 2 hyperpigmentation. Among the patients with >or= 3 years of follow-up, cosmesis was scored as good to excellent in 21 patients (91%) and fair in 2 patients (9%). At the time of this report, no ipsilateral or contralateral breast recurrences have occurred.

These data demonstrate the feasibility of treating the whole breast for DCIS with a hypofractionated regimen, with modest acute and late toxicity.