A new analysis of over 22,000 mastectomy patients confirms what smaller studies have indicated: Patients who undergo nipple-sparing mastectomy have overall and disease-free survival similar to that of those who receive a total mastectomy.
When nipple-sparing mastectomy was introduced, many experts felt uneasy about opting for the less invasive procedure, recalled Rosa Hwang, MD, associate medical director for breast surgery at MD Anderson Cancer Center in Houston. “The concern was leaving all this skin,” said Dr. Hwang. “Are you going to leave cancer behind” and increase the risk of local recurrence?
Over the past 2 decades, the number of patients undergoing nipple-sparing mastectomy increased and, in turn, studies began to demonstrate the safety of the procedure.
However, large analyses evaluating long-term outcomes – namely, overall survival and breast cancer-specific survival – of nipple-sparing mastectomy were still lacking.
The latest study, published online Nov. 20 in Annals of Surgical Oncology, compared the long-term prognosis and survival benefits of nipple-sparing to total mastectomy in thousands of women. The analysis, which pulled data from the SEER cancer database, included 5,765 patients who underwent the nipple-sparing procedure and 17,289 patients who had a total mastectomy.
The authors found that overall survival and breast cancer–specific survival were similar for women undergoing nipple-sparing mastectomy and those receiving a total mastectomy. In fact, over the long-term, the nipple-sparing group slightly edged out the total mastectomy group in overall survival (94.61% vs. 93% at 5 years and 86.34% vs. 83.48% at 10 years, respectively) and in breast cancer-specific survival rates (96.16% vs. 95.74% at 5 years, and 92.2% vs. 91.37% at 10 years). The differences, however, were not significant.
The study also found that certain subgroups – including White women, women over age 46, those with a median household income of $70,000 or more, hormone receptor-positive, and HER2 negative – had significantly better overall survival rate with the nipple-sparing procedure (P < .05). However, the authors noted, the survival advantage in the nipple-sparing group did not extend to breast cancer–specific survival.
Dr. Hwang, who was not involved in the current analysis, said the significant overall survival result in the subgroup analysis was surprising because “there’s no biological reason why one would expect that to be true.”
Given that the subgroups did not demonstrate better breast cancer–specific survival, Dr. Hwang believes the overall survival finding may have more to do with comorbidities, which the study did not account for, than type of mastectomy.
When choosing who is eligible for a nipple-sparing mastectomy, “We’re more selective,” Dr. Hwang said. For instance, patients with uncontrolled diabetes or who smoke are unlikely to be candidates. “So, I think it’s possible that medical comorbidities and medical conditions between these groups [were] different.”
According to the authors, coding inconsistencies represent another possible weakness of the study. From 1998 to 2010, “the term ‘nipple-sparing mastectomy’ was coded as a [total mastectomy] with the ‘subcutaneous mastectomy’ code.” It’s possible that some patients receiving the nipple-sparing procedure before 2011 were not appropriately coded in the current study.
Moving forward, a large prospective study that includes comorbidities would be helpful, but overall the study helps validate that “nipple-sparing mastectomy is a safe operation for selected patients,” Dr. Hwang said.
A version of this article first appeared on Medscape.com.