Rise in Double Mastectomies, No Decrease in Death Risk

An increasing number of women are opting for a bilateral mastectomy after an early-stage breast cancer diagnosis, according to the results of a new study. However, this large study shows that bilateral mastectomy offers no survival advantage compared to breast-conserving surgery (a lumpectomy) combined with radiation.

The results were published earlier this month in JAMA.

Allison W. Kurian, MD, MSc, of the Stanford University School of Medicine in California, and colleagues analyzed the records of 189,734 women in California who were diagnosed with early-stage disease between 1998 and 2011, comparing rates of death following unilateral mastectomy, bilateral mastectomy, and breast-conserving surgery.

A double mastectomy was not associated with a lower risk of death compared to breast-conserving surgery.

Unilateral mastectomy, however, was linked to a higher risk of death compared with the other two options. Women who had a unilateral mastectomy had a higher all-cause mortality (hazard ratio = 1.35; 95% CI, 1.32-1.39) and 20.1% 10-year mortality rate, compared with a 16.8% 10-year mortality rate for women who underwent breast-conserving surgery with radiation. There was no significant difference for patients in the double mastectomy group (18.8% 10-year mortality rate).

The rate of double mastectomies increased from 2% in 1998 to 12.3% by 2011-an annual increase of 14.3%. The most drastic increase was among women younger than 40 years of age (3.6% in 1998 compared to 33% in 2011-a 17.6% annual increase). Non-Hispanic, white women who were privately insured and who were treated at a National Cancer Institute (NCI)–designated cancer center were the most likely to opt for a double mastectomy. Rates of single mastectomies declined during the same period.

In total, 9,907 women had a double mastectomy, 96,462 had a lumpectomy, and 68,548 had a single mastectomy.

Unilateral mastectomies were more common among racial and ethnic minorities compared to non-Hispanic white women and those with public/Medicaid insurance.

The poorer survival among women who had a single mastectomy may be attributed to factors such as quality of care or lack of access to lumpectomy and radiation therapy, which were not accounted for in this study, the authors noted.

“In a time of increasing concern about overtreatment, the risk-benefit ratio of bilateral mastectomy warrants careful consideration and raises the larger question of how physicians and society should respond to a patient’s preference for a morbid, costly intervention of dubious effectiveness,” the authors wrote.

There are currently no randomized trials comparing survival differences among the different breast surgery procedures. According to the authors, a randomized trial is unlikely, as most women probably prefer having a choice of procedure.

Clinicians have generally not supported the increase in double mastectomies. Fear, the increased prevalence of genetic testing, increased breast MRI with higher rates of recall and biopsies, are all factors that may have contributed to the current trend. Still, “although fear of cancer recurrence may prompt the decision for bilateral mastectomy, such fear usually exceeds the estimated risk,” according to the authors.

Commenting on the study results in an accompanying editorial, Lisa A. Newman, MD, MPH, of the University of Michigan in Ann Arbor, wrote that although a breast cancer diagnosis comes with emotions that may impair the processing of information accurately, patients need to be accurately informed of acceptable and safe options before undergoing potentially hasty and irreversible surgeries.