Abstract P2-14-02: Get skin sparing mastectomy right: Reduce local recurrence rate by meticulous removal all breast tissue

Abstract

Abstract Background: Skin sparing mastectomy (SSM) was introduced to allow aesthetically better results when combined with breast reconstruction. However, preservation of a larger skin envelope than that left after standard mastectomy could lead to retention of significant amounts of residual breast tissue in the subcutaneous fat, increasing the risk of local recurrence or new breast cancers developing. Study method: Over a 15 year period, subcutaneous fat samples were routinely sampled during SSM and reconstruction performed by one surgeon. SSM was offered to all patients bar those with inflammatory cancers unresponsive to primary chemotherapy and those medically unfit for surgery. Hospital and personal databases of these cases were interrogated for: presence of breast epithelial tissue in subcutaneous fat samples local recurrence systemic recurrence aesthetic grade by independent surgeons Results: 402 SSM were reviewed. Results of subcutaneous samples were recorded for 357. 3 patients had residual breast tissue in subcutaneous fat samples (0.75%), 4 developed a local recurrence (1%), 42 systemic recurrence (11%). 238 patients had G1-3 invasive ductal carcinoma, size range 3-100mm, 25 invasive lobular carcinoma, 12.5-88mm and 87 DCIS, 20-116mm. These included patients who responded to preoperative chemotherapy and hormone therapy. 52 patients had prophylactic procedures. The aesthetic outcome was judged as good for 76%, moderate for 20%. The median follow up period was 9 years, giving annual local and systemic recurrence rates of 0.11% and 1.16% respectively. Conclusions: There was a low incidence of residual breast tissue in random subcutaneous fat samples collected during SSM (0.75%) The local recurrence rate was one tenth of the systemic recurrence rate, 1% vs 11%, and annual rates of 0.11% and 1.16% respectively. Discussion: Surgery for breast cancer is a local treatment, and though removal of the main tumor will contribute to systemic control, that will be achieved by a combination of local and systemic therapies based on the biology of the individual's disease. Once surgery is performed, it can have no further influence on systemic control. However, the meticulousness of the surgical procedure can influence subsequent local control. Residual breast tissue left after mastectomy may harbor areas of disease that may not respond to other adjuvant therapies leading to local recurrence, or separate new cancers. Traditionally it has been considered that some breast tissue will be retained in skin flaps post mastectomy, up to 5% with standard mastectomies. This study suggests that this can be avoided, even when a large skin envelope is retained for an aesthetic outcome, and lead to a marked reduction in local recurrence. Citation Format: Drabble EH. Get skin sparing mastectomy right: Reduce local recurrence rate by meticulous removal all breast tissue [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 P2-14-02.