Hypofractionated versus conventionally fractionated radiotherapy for ductal carcinoma in situ (DCIS) of the breast

Introduction: Hypofractionated radiotherapy (RT) in the setting of early invasive breast cancer has been shown to have similar local control rates and cosmetic outcomes as conventionally fractionated RT. This study compares ipsilateral recurrence rates between hypofractionated and conventional RT, with and without a boost. The effect of hypofractionated RT and chest wall separation (CWS) on cosmetic outcome was also assessed. Methods: All patients with ductal carcinoma in situ (DCIS) treated between 1998 and 2012 across two sites of a single cancer institution were retrospectively studied. Patients were analysed according to those receiving conventional RT (≤2 Gy per fraction) and those receiving hypofractionated RT (>2 Gy per fraction), as well as the presence or absence of a tumour bed boost. Data were collected through electronic medical records and local cancer registry. Cosmetic outcome was scored by physicians on a four-point scale during clinical follow-up appointments. Results: One hundred and ninety-seven patients were treated for DCIS during the study period. One hundred and forty-one were treated with conventional RT, and 56 with hypofractionated RT. After a median follow up of 4.4 years, there were 12 ipsilateral recurrences, of which seven were invasive disease and five DCIS. Ten recurrences occurred in patients who received conventional RT (7.1% recurrence rate) and two in those who received hypofractionated RT (3.6% recurrence rate) (P = 0.48). Cosmetic outcomes were not significantly different between conventional and hypofractionated RT (P = 0.06). Conclusions: Hypofractionation represents a suitable alternative for treating DCIS in the absence of randomised data.