What is the aim of this review?
We reviewed the evidence about the surgery technique called skin-sparing mastectomy (SSM) (that is, removing the breast tissue including the breast and areola (skin surrounding the nipple) but preserving all the skin that overlies the breast) compared to conventional mastectomy (that is, removing the skin that overlies the breast including nipple and areola).
We found that SSM may not be different from conventional mastectomy for the risk of cancer recurring in the breast area only (local recurrence), chance of dying of breast cancer (overall survival) or risk of complications after surgery. Complications after surgery which were assessed included breast reconstruction loss (where the breast reconstruction flap or implant needs to be surgically removed due to complications), skin necrosis, local infection, hemorrhage (bleeding), quality of life, and cosmetic results. The results of this review are based on 14 studies and most of these with likely biased due to flaws in their design.
What is skin-sparing mastectomy?
Conventional mastectomy for breast cancer is a surgical procedure consisting of removing the entire breast tissue, the skin that overlies the breast, and the nipple-areola complex. The chance of cancer returning to the chest wall (site of mastectomy) after this type of surgery is about 2.3% after 20 years. Trying to improve cosmetic results has led to the use of skin-sparing mastectomy (SSM) as an alternative to conventional mastectomy. Preserving as much of the breast skin as possible leaves minimal breast tissue and provides higher psychological satisfaction and the perception of less injury. SSM has been used for the treatment of breast cancer for the last two decades.
What did we want to find out?
We wanted to find out if SSM is as effective to treat breast cancer as conventional mastectomy and assess whether the surgical complication rates differed.
What did we do?
We searched for studies that compared SSM with other types of mastectomies for the treatment of breast cancer. We compared and summarized the results of the studies and rated our confidence in the evidence based on factors such as study methods and sizes.
What did we find?
We found 14 cohort studies (longitudinal studies that follow people over time) involving 12,283 surgeries where 3183 people underwent an SSM and 9100 underwent a conventional mastectomy.
People who had an SSM or conventional mastectomy may have similar:
- chance of cancer returning after surgery (1 study)
- survival (2 studies)
- risk of overall complications (4 studies)
- risk of removing the breast reconstruction flap or implant due to complications (3 studies)
- risk of skin necrosis (4 studies)
- risk of infection (2 studies)
- risk of hemorrhage (4 studies)
However, the evidence is very unclear.
Based on one study, there did not appear to be a difference in aesthetic outcomes between SSM with immediate breast reconstruction compared to conventional mastectomy and delayed breast reconstruction. One study evaluated the quality of life. The study suggested similar patient satisfaction, social activity, physical aspects, and general condition in people who have an SSM followed by breast reconstruction and those who have a mastectomy without breast reconstruction.
What are the limitations of the evidence?
The studies found were mostly retrospective. This means that participants were chosen years after their surgery, and asked about their experiences after surgery, which may have brought bias into the research studies. Of the 14 studies, two studies commenced at the time of surgery.
People who had conventional mastectomy were likely different to those who had SSM. Most studies did not consider these differences across groups when analyzing the data.
How up to date is this evidence?
The review authors searched for studies that had been published up to August 2019.
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.
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.
To assess the effectiveness and safety of skin-sparing mastectomy for the treatment of breast cancer.
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.
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.
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.
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, I2 = 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, I2 = 33%; 4 studies, 677 participants; very low-certainty evidence), local infection (RR 2.04, 95% CI 0.03 to 142.71; P = 0.74, I2 = 88%; 2 studies, 371 participants; very low-certainty evidence), nor hemorrhage (RR 1.23, 95% CI 0.47 to 3.27; P = 0.67, I2 = 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.