NATIONAL HARBOR, MD. – The rate of contralateral prophylactic mastectomies is rising, even though there is no evidence for a survival benefit.
From 1998 through 2007, contralateral prophylactic mastectomies (CPM) were performed within 1 year of unilateral mastectomies in 21% of those with ductal carcinoma in situ (DCIS) and in 17% of those with stage I-III breast cancer who were treated at one of 10 National Comprehensive Cancer Network (NCCN) centers.
Dr. William Carson
But in an analysis of overall survival for patients with stages I-III invasive breast cancer, there was so significant difference in overall survival for patients who underwent a CPM, compared with those who underwent only unilateral mastectomy, regardless of whether they had received neoadjuvant chemotherapy, reported Dr. William E. Carson III, professor of surgery at the Ohio State University Comprehensive Cancer Center in Columbus.
In addition, CPMs are associated with a significantly greater risk of complications than unilateral mastectomies, including increased risk for major complications requiring reoperation and rehospitalization, said Dr. Megan Miller, a surgery resident at the University of Chicago, Illinois.
"CPM patients are 1.5 times more likely to have any complication, and 2.6 times more likely to have a major complication than unilateral mastectomy patients," she said at the annual Society of Surgical Oncology Cancer Symposium.
Among patients who underwent CPM, almost 40% of the complications occurred on the side of the body without cancer, she noted.
SSO position statement
A 2007 position statement from the Society of Surgical Oncology (SSO) states that in patients with a current or prior diagnosis, CPM may be indicated for risk reduction in cases where surveillance is difficult or for reconstructive issues such as symmetry and balance, Dr. Carson noted.
Two studies using Surveillance, Epidemiology, and End Results (SEER) data (Tuttle et al. [J. Clin. Oncology 2009;27:1362-7]); Bedrosian et al. [J. Natl. Cancer Inst. 2010;102:401-9]) and one from his own center (Jones et al. [Ann. Surg. Oncol. 2009;16:2691-6]) showed about a 10% increase in the rate of CPM over a decade. Younger women with higher levels of education were more likely to seek CPM.
To see whether this trend extended to NCCN centers, Dr. Carson and his colleagues reviewed data on 1,309 women with DCIS, and 7,044 with stage I-III breast cancer who underwent unilateral mastectomy from 1998 through 2007 at one of 10 designated centers.
In all, 273 of the women diagnosed with DCIS (21%) had a contralateral prophylactic mastectomy, as did 1,199 (17%) of the women with a diagnosis of stage I-III invasive disease. Median follow-up was more than 4 years for both groups.
In a multivariate analysis, factors that significantly predicted the likelihood of CPM included age younger than 50 years, Caucasian race, MRI as the method of detection, and tumor size of 1 cm or smaller. In women with invasive disease, years of education, node-negative status, and no immediate reconstruction were also significant predictors of CPM (P less than .0001 for all variables).
Use of CPM varied widely by institution from 8.2%-34.7% of women with DCIS, and from 3.6%-30.8% of patients with stage I-III disease. As other studies have shown, the use of CPM increased over time, from 15% for DCIS in 1998 to 27% in 2007. For patients with invasive breast cancer, the respective increase was from 8% to 26%. The most pronounced increases were among patients younger than 50 years, Dr. Carson noted.
When they looked at overall survival in a multivariate Cox regression model adjusted for age, race, tumor size, nodal status, tumor grade, histology, and treatment, they found that there was no significant survival advantage for unilateral mastectomy plus CPM, compared with unilateral mastectomy alone.
Dr. Megan Miller
Complications, complications
Dr. Miller and her colleagues retrospectively reviewed 600 patients who underwent either unilateral mastectomy (391) or CPM (209) at their center from January 2009 through March 2012. They looked at major complications such as seroma or hematoma requiring reoperations, infections requiring hospital admission, total nipple or flap necrosis, and bleeding requiring transfusion; and minor complications such as seromas and hematomas requiring aspiration, infections requiring oral antibiotics, partial nipple or flap necrosis, minor bleeding, and delayed wound healing.
The percentage of patients experiencing any complications was 29% for patients who had a unilateral mastectomy, compared with 42% of those who underwent CPM (P less than .001). Major complications occurred in 4.1% and 14%, respectively (P less than .001). Rates of minor complications were identical between the groups, at 15% each.
Multiple major complications were seen in 4.9% of unilateral patients, compared with 9.1% of CPM patients (P = .043).