Evaluation of residual glandular tissue after skin-sparing mastectomies

Background: The oncological safety of skin-sparing mastectomy (SSM) has been the object of several studies. Methods: From June 2003 to January 2004, 42 breast cancer patients, stage 0 to IIIA, underwent SSM. Before surgery, two lines were drawn on the breast skin, representing SSM and conventional mastectomy incisions. After surgery, the skin flap that would remain after SSM was removed, and immediate breast reconstruction was begun. The presence and amount of remaining glandular breast tissues were histologically evaluated in the skin flap. Terminal ductal lobular units (TDLUs) and residual disease were identified. These data were correlated with other clinical and pathologic parameters by using Fisher's exact test (P value) and receiver operating characteristic curves. Results: The prevalence of residual breast tissue in the sample was 59.5%, and the presence of TDLUs was significantly associated with skin flaps thicker than 5 mm. Residual disease was found in 9.5% of the women and was associated with skin flaps > 5 mm thick and the presence of TDLUs. There was no significant association between the presence of TDLUs and residual disease with age, body mass index, menopausal status, clinical and pathologic staging, breast volume, mammographic density, neoadjuvant chemotherapy, type of surgery, and presence of an extensive in situ component. The receiver operating characteristic curve showed that as skin flaps decrease in thickness, TDLUs also decrease. Conclusions: A high prevalence of glandular breast tissue and residual disease in the skin flap was associated with a skin flap thickness > 5 mm.