The efficacy and safety of nipple-sparing mastectomy and areola-sparing mastectomy for the treatment of breast cancer are still questionable. It is estimated that the local recurrence rates following nipple-sparing mastectomy are very similar to breast-conserving surgery followed by radiotherapy.
To assess the efficacy and safety of nipple-sparing mastectomy and areola-sparing mastectomy for the treatment of ductal carcinoma in situ and invasive breast cancer in women.
We searched the Cochrane Breast Cancer Group's Specialized Register, the Cochrane Center Register of Controlled Trials (CENTRAL), MEDLINE (via PubMed), Embase (via OVID) and LILACS (via Biblioteca Virtual em Saúde [BVS]) using the search terms "nipple sparing mastectomy" and "areola-sparing mastectomy". Also, we searched the World Health Organization's International Clinical Trials Registry Platform and ClinicalTrials.gov. All searches were conducted on 30th September 2014 and we did not apply any language restrictions.
Randomised controlled trials (RCTs) however if there were no RCTs, we expanded our criteria to include non-randomised comparative studies (cohort and case-control studies). Studies evaluated nipple-sparing and areola-sparing mastectomy compared to modified radical mastectomy or skin-sparing mastectomy for the treatment of ductal carcinoma in situ or invasive breast cancer.
Two review authors (BS and RR) performed data extraction and resolved disagreements. We performed descriptive analyses and meta-analyses of the data using Review Manager software. We used Cochrane's risk of bias tool to assess studies, and adapted it for non-randomised studies, and we evaluated the quality of the evidence using GRADE criteria.
We included 11 cohort studies, evaluating a total of 6502 participants undergoing 7018 procedures: 2529 underwent a nipple-sparing mastectomy (NSM), 818 underwent skin-sparing mastectomy (SSM) and 3671 underwent traditional mastectomy, also known as modified radical mastectomy (MRM). No participants underwent areola-sparing mastectomy. There was a high risk of confounding for all reported outcomes. For overall survival, the hazard ratio (HR) for NSM compared to SSM was 0.70 (95% CI 0.28 to 1.73; 2 studies; 781 participants) and the HR for NSM compared to MRM was 0.72 (95% CI 0.46 to 1.13; 2 studies, 1202 participants). Local recurrence was evaluated in two studies, the HR for NSM compared to MRM was 0.28 (95% CI 0.12 to 0.68; 2 studies, 1303 participants). The overall risk of complications was different in NSM when compared to other types of mastectomy in general (RR 0.10, 95% CI 0.01 to 0.82, 2 studies, P = 0.03; 1067 participants). With respect to skin necrosis, there was no evidence of a difference with NSM compared to other types of mastectomy, but the confidence interval was wide (RR 4.22, 95% CI 0.59 to 30.03, P = 0.15; 4 studies, 1948 participants). We observed no difference among the three types of mastectomy with respect to the risk of local infection (RR 0.95, 95% CI 0.44 to 2.09, P = 0.91, 2 studies; 496 participants). Meta-analysis was not possible when assessing cosmetic outcomes and quality of life, but in general the NSM studies reported a favourable aesthetic result and a gain in quality of life compared with the other types of mastectomy. The quality of evidence was considered very low for all outcomes due to the high risk of selection bias and wide confidence intervals.
The findings from these observational studies of very low-quality evidence were inconclusive for all outcomes due to the high risk of selection bias.