Background: Given the prevalence of female breast cancer in the United States, large volume displacement (Level II) oncoplastic breast surgery is becoming an increasingly common technique to remove cancerous breast tissue. It allows for the removal of the cancerous tissue with a large partial mastectomy followed by a mastopexy or breast reduction oncoplastic reconstruction design. A contralateral symmetry operation using similar mastopexy or breast reduction designs are many times also performed, often by a plastic surgeon. Our goal was to determine the rates of high risk and malignant lesions present in the contralateral breast specimen.

Methods: We conducted a retrospective chart review of the first consecutive 100 large volume displacement oncoplastic breast surgeries performed at our institution between August 2015 and June 2018. Of the 100 cases, 84 patients had an immediate symmetry operation performed on the contralateral breast. Our inclusion criteria for malignant lesions included invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS). Inclusion criteria for high risk lesions included atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS). We obtained this information from the patient's pathology report.

Results: Of the 84 patients that underwent a symmetry operation on the contralateral breast, 14 patients (16.7%) had malignant and/or high risk lesions incidentally detected. Two patients (2.4%) had IDC, 1 (1.2%) had DCIS alone, 1 (1.2%) had DCIS with ADH, 6 (7.1%) had ADH alone, 2 (2.4%) had ALH, and 2 (2.4%) had LCIS. For those who had IDC in the contralateral breast, average reported incidental tumor size was 6.5 mm at its largest point. The majority of these lesions (57%) were found when performing in superomedial pedicle inverted T (Wise) skin incision pattern specimens. 3 (21%) were found using the inferior pedicle inverted T (Wise) skin pattern, 2 (14%) were found using the superomedial pedicle circumvertical skin incision pattern, and 1 (7%) was found using the superior pedicle circumvertical skin incision pattern.

Conclusion: The high incidence of cancer and high risk lesions incidentally detected in the contralateral breast highlights the need for consistent histological examination of the contralateral specimen. These results suggest the need for proper orientation of the specimen and good communication between the surgical (often the plastic surgeons performing the symmetry operation) and pathology teams. Such communication is needed to help target any future surgeries that may be required due to positive margins in the contralateral symmetry specimen.

Citation Format: Muse-Fisher C, Rambukwella M, Liang Y, Naber S, Chatterjee A. Rates of high risk and malignant lesions incidentally detected in the contralateral breast after large volume displacement oncoplastic breast surgery [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-22-02.