Oncoplastic Mammoplasty with disguised geometric compensation.

[OBJECTIVE] To evaluate the results of a cohort of patients submitted to a new technique of oncoplastic mammoplasty, referred to as Disguised Geometric Compensation Mammoplasty (GCM), which is suitable for tumours involving the glandular tissue in the pillars of the mammoplasty.

[MATERIALS AND METHODS] Twenty-five breast tumours involving the pillars of the mammoplasty were included, 20 (80.0%) invasive ductal carcinomas, 3 (12.0%) phyllodes tumours, 1 (4.0%) invasive lobular carcinoma, and 1 (4.0%) in situ ductal carcinoma. Preoperative markings followed the "Wise-pattern" technique. The resection of the tumour in the pillar, preserving the overlying skin, was geometrically compensated with a corresponding area coming from the lower poles, which folded over itself and maintained the skin vascularity in the pillar. One patient was converted to classic GCM due to a positive skin margin in the frozen section. Another patient combined a Classic GCM for the inner quadrants and a Disguised GCM for the outer quadrants on the same breast. One patient decided to undergo a bilateral mastectomy after some months because of a BRCA 1 mutation. Immediate fat grafting was done in one case. Approval from the ethics committee: n. 2.322.212.

[RESULTS] Mean age was 47.0 ± 9.5 years. Mean clinical tumour size was 47.2 ± 22.2mm before chemotherapy and 36.7 ± 22.5mm, after. There were 11 (44.0%) locally advanced and 1 (4.00%) multicentric tumours. Nine (36.0%) were submitted to neoadjuvant chemotherapy. Adjuvant treatment was indicated according to the necessity. Ptosis was corrected in all cases. The aesthetic results were rated as excellent or good in 21 (95.5%) cases, by the Harris scale and the BCCT.core. The BREAST-Q scores for the satisfaction with the breasts and satisfaction with outcomes were 81.5 (±15.0) and 90.4 (±11.7), respectively. Intraoperative frozen sections were done in 12 (48%) cases. There was 1 (4.0%) focus of DCIS in the skin margin treated with radiotherapy. Minor complications occurred in 6 (24.0%) patients. There was 1 (4.0%) local recurrence treated with radical mastectomy, and 1 (4.0%) metastasis after 3 months. No deaths were observed within a mean follow-up time of 16.3 ± 11.4 months.

[CONCLUSIONS] The disguised geometric compensation mammoplasty allowed breast conservation in situations requiring large resection in the pillars of the mammoplasty, with a high rate of free margins, correction of ptosis, satisfactory symmetry, and few complications.