Occult cancer in specimens of reduction mammaplasty aimed at symmetrization. A multicentric study of 2718 patients

International audienceWomen who have undergone surgical treatment for breast cancer often benefit from a contralateral reduction mammaplasty (CRM) aimed at symmetrization of the contralateral breast unaffected by the initial cancer. In our 7-year multicentric study (12 centers) of 2718 patients, incidence of CRM cancers (CRMc) was 1.47% (n = 40) [95% CI 1.05%-2.00%]. The CRMc group had significantly more initial mammary cancers of invasive lobular carcinoma (ILC, 22.5% vs 12.0%) and ductal carcinoma in situ (DCIS, 35.0% vs 21.6%) types than the healthy CRM group (p = 0.017). 35.0% (n = 14) of patients had en bloc resection; 25.0% (n = 10) of surgical specimens were correctly oriented. En bloc resection and orientation of surgical specimens enable precise pinpointing of the CRMc. A salvage lumpectomy may be proposed as an option when margins are invaded. The histological distribution of the 40 CRMc (mean size 12.7 mm) was carcinoma in situ (CIS) 70%, ILC 12.5%, invasive ductal carcinoma (IDC) 12.5% and tubular carcinoma (TC) 5.0%