Oncoplastic Level 2 Mammoplasty for Large DCIS: 5-Year Results.

Background: Oncoplastic surgery (OPS) allows wider resections with immediate breast reshaping by mammoplasty. This study reviews our experience with level 2 mammoplasties in patients with histology-proven pure ductal carcinoma in situ (DCIS).

Method: From a prospectively maintained database of 392 consecutive oncoplastic level 2 mammoplasties, 68 patients presented with pure DCIS. Involved margin rates and locoregional recurrence rates were calculated, with 76 months (0-166 months) median follow-up.

Results: The mean pathological tumor size was 34 mm (median 26 mm, range 2-106 mm). The mean resection weight was 191 g (median 131 g, range 40-1150 g). Margins were clear in 58 cases (85.3%) and involved in 10 cases (14.7%). Margins were involved in 1 out of 54 (1.9%) cases with tumor size under 50 mm and in 9 out of 14 (64.3%) cases with tumor size higher than 50 mm (p < 0.001). On multivariable analysis, only tumor size > 50 mm [odds ratio (OR) 95.400; p < 0.001] was independently associated with involved margins. Seven patients had mastectomy. The overall breast conservation rate was 89.4%, and 100% for tumors less than 5 cm. There were three local recurrences. The 5-year cumulative incidence for local recurrence was 5.5% (0-11.5%).

Conclusions: OPS is a safe solution for large DCIS up to 50 mm, with an involved margin rate of only 1.9%, and can thus reduce the mastectomy rate in this group. As margin involvement significantly increases for tumors larger than 5 cm, better preoperative localization and/or wider excisions are necessary in this group.