Use of prophylactic mastectomy increasing among younger women with early-stage breast cancer
More than one-third of women aged 20 to 44 years who underwent surgery for invasive unilateral breast cancer elected to remove the unaffected breast for preventive reasons, according to a retrospective study published in JAMA Surgery.
The proportion of those women varied greatly by state, with Virginia showing an increase in use of contralateral prophylactic mastectomy from 9.8% between 2004 and 2006 to 32.2% between 2010 and 2012.
“Nobody knows exactly why, but Angelina Jolie choosing to remove her breasts [in 2013] drew a lot of media coverage and there was a slight uptick after that,” Ahmedin Jemal, DVM, PhD, vice president of surveillance and health services research at the American Cancer Society, told HemOnc Today.
Still, researchers had observed an increase in contralateral prophylactic mastectomy prior to Jolie’s decision, Jemal said.
“One reason may be that women have anxiety about developing a secondary cancer in the unaffected breast, and they make a decision without fully understanding the benefits and risks of having this procedure,” he said. “They may not take the time to assess all the options they have.”
Jolie, aged 37 years at the time of her double mastectomy, learned she carried a mutation of the BRCA1 gene and had an 87% chance of developing breast cancer because of a family history of cancer.
Women with invasive unilateral breast cancer without a BRCA mutation have a 2% to 4% chance of developing a secondary cancer in the unaffected breast over the span of 10 years, Jemal said.
“In other words, between 94% and 98% of women diagnosed with unilateral breast cancer will not develop breast cancer in the breast which was not affected by cancer previously,” he said. “The problem is, I don’t think women are informed of this or have taken time to process this information.”
Increase in surgical procedures
Despite lack of evidence for survival benefit, several studies in the United States have reported an increase in the use of contralateral prophylactic mastectomy — also called bilateral mastectomy — particularly for women aged younger than 45 years. However, it was unclear how this trend varied by state or whether it correlated with changes in proportions of reconstructive surgery.
Jemal and colleagues used the North American Association of Central Cancer Registries to identify a cohort of more than 1.2 million women aged 20 years or older diagnosed with invasive unilateral early-stage breast cancer and treated with surgery between 2004 and 2012 in 45 states and the District of Columbia.
The proportion of women aged 20 to 44 years who underwent bilateral mastectomy increased from 10.5% in 2004 to 33.3% in 2012. Among women aged 45 years or older, the proportion increased from 3.6% in 2004 to 10.4% in 2012.
Ethnicity and size of tumor appeared linked to use of contralateral prophylactic mastectomy. Among white women, 9.3% elected to undergo the procedure compared with 5.7% of black women and 7.2% of Hispanic women. Women with tumors 5 cm or larger appeared more likely to undergo bilateral mastectomy than those with tumors smaller than 2 cm (14% vs. 7.2%).
The use of contralateral prophylactic mastectomy was greater among women aged 20 to 29 years (29.3%) and 30 to 39 years (25.3%) than those aged 40 to 49 years (15.5%) and 50 to 59 years (9.6%).
All states, except Wyoming. showed an increase from 2004-2006 to 2010-2012 in contralateral prophylactic mastectomy among women aged 20 to 44 years; although, the magnitude of those increases varied substantially.
For example, the proportion of contralateral prophylactic mastectomies increased about three-fold in Virginia (prevalence ratio = 3.29; 95% CI, 2.8-3.88) and Kentucky (prevalence ratio = 3.03; 95% CI, 1.46-1.89), whereas the corresponding increase was less than two-fold in several states, including New Jersey (prevalence ratio = 1.66; 95% CI, 1.46-1.89).
In 2010 to 2012, the proportion of contralateral prophylactic mastectomies varied from 15.7% in Hawaii to greater than 42% in the contiguous states of Nebraska, Missouri, Colorado, Iowa and South Dakota.
The proportion of contralateral prophylactic mastectomies among women aged 45 years or older also increased in all states from 2004-2006 to 2010-2012, except for the District of Columbia, which remained stable.
From 2004 to 2012, reconstructive surgical procedures among patients aged 20 years or older increased from 11.6% in 2004 to 21.5% among those undergoing unilateral mastectomy and from 39.5% to 54.8% among those undergoing bilateral mastectomy. A greater proportion of younger than older women had reconstructive surgery following unilateral mastectomy (37.4% vs. 19.4%) and bilateral mastectomy (66.8% vs. 49.9%).
However, the increase in reconstructive surgery did not correlate with the proportion of women who received bilateral mastectomy.
Guidelines for use
Jemal said he hopes more oncologists review the five recommendations made by the American Society of Breast Surgeons in June 2016. These recommendations include that clinicians of patients with breast cancer should not routinely:
- order breast MRI in new patients;
- excise all the lymph nodes beneath the arm in patients having lumpectomy;
- order specialized tumor gene testing in all new patients;
- re-operate on patients with invasive cancer if the cancer is close to the edge of the excised lumpectomy tissue; and
- perform a bilateral mastectomy in patients who have a single breast with cancer.
“Patients listen to their doctors, and there are previous studies that show that when recommendations are given by the physicians or surgeons, women are more likely to have contralateral prophylactic mastectomy,” Jemal said. “But, there are also surveys that show almost half of women were not informed about the risks or lack of benefit of contralateral prophylactic mastectomy. Doctors or surgeons have to do a better job of explaining.”
Contralateral prophylactic mastectomies should be a consideration only among patients ineligible for, or unwilling to accept, breast-conserving surgery for unilateral breast cancer, Lisa A. Newman, MD, MPH, director of the breast oncology program at Henry Ford Health System, wrote in an accompanying editorial.
“Several studies have shown that white American identity and affluence are associated with decisions to undergo contralateral prophylactic mastectomy,” Newman wrote. “Interestingly, four of the five Midwestern states with the highest rates of contralateral prophylactic mastectomy have African American populations no larger than 5% and poverty rates below the 14% national rate.”
Newman noted that physicians must respect patient choice and avoid being paternalistic, but also must protect patients from making “impulsive surgical decisions when they are freshly encumbered by the panic accompanying a new diagnosis of breast cancer.” – by Chuck Gormley
For more information:
Ahmedin Jemal, DVM, PhD, can be reached at Surveillance and Health Services Research, American Cancer Society, 250 Williams St. NW, Atlanta, GA 30303; email: firstname.lastname@example.org.
Disclosure: The American Cancer Society funded this study. Researchers report no relevant financial disclosures.