Skin-sparing mastectomy for the treatment of breast cancer.

BACKGROUND

Skin-sparing mastectomy (SSM) is a surgical technique that aims to maximize skin preservation, facilitate breast reconstruction, and improve cosmetic outcomes. Despite its use in clinical practice, the benefits and harms related to SSM are not well established.

OBJECTIVES

To assess the effectiveness and safety of skin-sparing mastectomy for the treatment of breast cancer.

SEARCH METHODS

We searched Cochrane Breast Cancer's Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, the World Health Organization's International Clinical Trials Registry Platform (WHO ICTRP), and ClinicalTrials.gov on 9 August 2019.

SELECTION CRITERIA

Randomized controlled trials (RCTs), quasi-randomized or non-randomized studies (cohort and case-control) comparing SSM to conventional mastectomy for treating ductal carcinoma in situ (DCIS) or invasive breast cancer.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. The primary outcome was overall survival. Secondary outcomes were local recurrence free-survival, adverse events (including overall complications, breast reconstruction loss, skin necrosis, infection and hemorrhage), cosmetic results, and quality of life. We performed a descriptive analysis and meta-analysis of the data.

MAIN RESULTS

We found no RCTs or quasi-RCTs. We included two prospective cohort studies and twelve retrospective cohort studies. These studies included 12,211 participants involving 12,283 surgeries (3183 SSM and 9100 conventional mastectomies). It was not possible to perform a meta-analysis for overall survival and local recurrence free-survival due to clinical heterogeneity across studies and a lack of data to calculate hazard ratios (HR).  Based on one study, the evidence suggests that SSM may not reduce overall survival for participants with DCIS tumors (HR 0.41, 95% CI 0.17 to 1.02; P = 0.06; 399 participants; very low-certainty evidence) or for participants with invasive carcinoma (HR 0.81, 95% CI 0.48 to 1.38; P = 0.44; 907 participants; very low-certainty evidence). For local recurrence-free survival, meta-analysis was not possible, due to high risk of bias in nine of the ten studies that measured this outcome. Informal visual examination of effect sizes from nine studies suggested the size of the HR may be similar between groups. Based on one study that adjusted for confounders, SSM may not reduce local recurrence-free survival (HR 0.82, 95% CI 0.47 to 1.42; P = 0.48; 5690 participants; very low-certainty evidence).  The effect of SSM on overall complications is unclear (RR 1.55, 95% CI 0.97 to 2.46; P = 0.07, I = 88%; 4 studies, 677 participants; very low-certainty evidence). Skin-sparing mastectomy may not reduce the risk of breast reconstruction loss (RR 1.79, 95% CI 0.31 to 10.35; P = 0.52; 3 studies, 475 participants; very low-certainty evidence), skin necrosis (RR 1.15, 95% CI 0.62 to 2.12; P = 0.22, I = 33%; 4 studies, 677 participants; very low-certainty evidence), local infection (RR 2.04, 95% CI 0.03 to 142.71; P = 0.74, I = 88%; 2 studies, 371 participants; very low-certainty evidence), nor hemorrhage (RR 1.23, 95% CI 0.47 to 3.27; P = 0.67, I = 0%; 4 studies, 677 participants; very low-certainty evidence). We downgraded the certainty of the evidence due to the risk of bias, imprecision, and inconsistency among the studies. There were no data available on the following outcomes: systemic surgical complications, local complications, explantation of implant/expander, hematoma, seroma, rehospitalization, skin necrosis with revisional surgery, and capsular contracture of the implant. It was not possible to perform a meta-analysis for cosmetic and quality of life outcomes due to a lack of data. One study performed an evaluation of aesthetic outcome after SSM: 77.7% of participants with immediate breast reconstruction had an overall aesthetic result of excellent or good versus 87% of participants with delayed breast reconstruction.

AUTHORS' CONCLUSIONS: Based on very low-certainty evidence from observational studies, it was not possible to draw definitive conclusions on the effectiveness and safety of SSM for breast cancer treatment. The decision for this technique of breast surgery for treatment of DCIS or invasive breast cancer must be individualized and shared between the physician and the patient while considering the potential risks and benefits of available surgical options.