Oncoplastic breast surgery for the management of ductal carcinoma in situ (DCIS): is it oncologically safe? A retrospective cohort analysis.

Background: Few data exist in literature regarding oncoplastic surgery (ONC) and ductal carcinoma in situ (DCIS). The role of ONC in the treatment of DCIS has not been elucidated yet: no case-control study has yet been published on the issue and no long-term oncologic results are reported.

Methods: Using the European Institute of Oncology (IEO) institutional breast cancer data base we investigated the oncologic safety of ONC for DCIS comparing a consecutive series of 44 patients who have underwent ONC followed by external irradiation for DCIS (Group A-study group) with 375 patients who received conservation alone followed by external irradiation for DCIS (Group B control group) in the same period. We excluded patients presenting with secondary tumors or local relapses and those requiring re-excision or completion mastectomy for positive margins. Primary endpoints were disease-free survival (DFS) and ipsilateral breast tumor recurrence (IBTR) within the study group and comparison with the control group.

Results: Events rates and death rates were similar in the two groups. The average annual rate of invasive IBTR in group A and B was 1.6% and 1.0% respectively. No difference in the rate of lymphnode metastasis, distant metastasis, contralateral breast cancer, other primary cancer or death was observed across the two groups.

Conclusions: Our findings suggest the safety of ONC and irradiation for the management of DCIS extending the indications for conservation in DCIS patients otherwise treated with mastectomy. It provides the best available evidence supporting ONC as a valid treatment option for the management of DCIS.