Local control with conventional and hypofractionated adjuvant radiotherapy after breast-conserving surgery for ductal carcinoma in-situ☆

Abstract 

Purpose

Adjuvant whole breast radiotherapy (WBRT) for ductal carcinoma in situ (DCIS) improves local control, however an optimal dose fractionation remains undefined. WBRT following breast-conserving surgery for invasive breast cancer demonstrates equivalent efficacy and morbidity for conventional and hypofractionated treatment. Our group policy allowed for the use of both schedules, therefore we compared local control in women with DCIS following breast-conserving surgery.

Patients and methods

Two hundred and sixty-six patients treated between January 1999 and December 2004 with conventional (50Gy in 25 fractions) or hypofractionated (42.4Gy in 16 fractions or 40Gy/16+12.5Gy boost) WBRT after breast-conserving surgery for DCIS were retrospectively reviewed. Median follow-up was 3.76years (range 0.1–8.9years).

Results

One hundred and four patients (39%) were treated with conventional and 162 (61%) with hypofractionated WBRT. The median age was 56.7years (range 32.2–83.8years), and prognostic features were well matched in both groups, apart from a small increase in tumour size in the conventional arm (1.75 vs. 2.12cm, p=0.05). Actuarial risk of recurrence at 4years was 7% with hypofractionated WBRT and 6% with the conventional schedule (p=0.9). Univariate analysis showed an increased risk of recurrence with high nuclear grade tumours (11% at 4years for grade 3 vs. 4% for grade 1/2, p=0.029).

Conclusions

Hypofractionated adjuvant WBRT following breast-conserving surgery for DCIS has comparable local control to a conventional radiation schedule. Hypofractionated WBRT is more convenient for patients, has equivalent morbidity and should be considered in this patient group.

Keywords: Ductal carcinoma in situ, Radiotherapy