Breast conservative surgery for well-differentiated ductal intraepithelial neoplasia : risk factors for ipsilateral breast tumor recurrence

Rational: We retrospectively analyzed 232 patients affected by well differentiated ductal intraepithelial neoplasia (DIN1c or DCIS G1) treated with conservative surgery without adjuvant radiotherapy. Results: 25 invasive and 18 non-invasive local recurrences were observed ( median follow-up 80 months; 5-year cumulative incidence: 12.2%). Seven of the 15 young patients (<40 y) developed local recurrence (2 in situ, 5 invasive). Age <50 (HR 1.89, 95% C.I. 1.01-3.45), multifocality (HR 3.21, 95% C.I. 1.46-7.06), Ki-67 > 7% (HR 2.33, 95% C.I. 1.20-4.55) and surgical margins <10 mm (HR 2.00, 95% C.I. 1.06-3.76) were significantly associated with an increased risk of local recurrence. Conclusions: Young age, multifocality and small margins appeared as clear risk factors of local recurrence in DIN1c (DCIS G1) population. The presence of multiple poor prognostic features warrant a thorough discussion regarding local treatment.