Incidental breast carcinoma: incidence, management, and outcomes in 4804 bilateral reduction mammoplasties.

[INTRODUCTION] Bilateral reduction mammoplasty is one of the most common plastic surgery procedures performed in the U.S. This study examines the incidence, management, and prognosis of incidental breast cancer identified in reduction specimens from a large cohort of reduction mammoplasty patients.

[METHODS] Breast pathology reports were retrospectively reviewed for evidence of incidental cancers in bilateral reduction mammoplasty specimens from five institutions between 1990 and 2017.

[RESULTS] A total of 4804 women met the inclusion criteria of this study; incidental cancer was identified in 45 breasts of 39 (0.8%) patients. Six patients (15%) had bilateral cancer. Overall, the maximum diagnosis by breast was 16 invasive cancers and 29 ductal carcinomas in situs. Thirty-three patients had unilateral cancer, 15 (45.5%) of which had high-risk lesions in the contralateral breast. Twenty-one patients underwent mastectomy (12 bilateral and nine unilateral), residual cancer was found in 10 in 25 (40%) therapeutic mastectomies. Seven patients did not undergo mastectomy received breast radiation. The median follow-up was 92 months. No local recurrences were observed in the patients undergoing mastectomy or radiation. Three of 11 (27%) patients who did not undergo mastectomy or radiation developed a local recurrence. The overall survival rate was 87.2% and disease-free survival was 82.1%.

[CONCLUSIONS] Patients undergoing reduction mammoplasty for macromastia have a small but definite risk of incidental breast cancer. The high rate of bilateral cancer, contralateral high-risk lesions, and residual disease at mastectomy mandates thorough pathologic evaluation and careful follow-up of these patients. Mastectomy or breast radiation is recommended for local control given the high likelihood of local recurrence without either.