Despite the lack of evidence that it will improve their chance of survival, almost half of young breast cancer patients in five states undergo preventive mastectomy to remove the unaffected breast.

These were the findings of a new study co-led by the American Cancer Society and published in JAMA Surgery.

About 252,710 new cases of invasive breast cancer are expected to be diagnosed in women this year, according to the ACS. About 40,610 women will die from the disease.
Preventive mastectomy for women diagnosed with early-stage breast cancer is recommended for those patients with BRCA 1/2 mutation and for those with a family history of the disease.

"However, these women at high risk for developing breast cancer in the unaffected breast represent a small proportion of patients to justify the high proportion of preventive mastectomy across the United States documented in our study," Ahmedin Jemal, senior author and vice president of surveillance and health services research and the ACS, told HCB News.

For the study, investigators at the ACS, Emory University, Dana-Farber Cancer Institute and Brigham and Women's Hospital analyzed data from the North American Association of Central Cancer Registries.

The data involved 1.2 million women ages 20 and older who were diagnosed with invasive unilateral early-stage breast cancer and underwent surgery between January 1, 2004 and December 31, 2012 in 45 states and the District of Columbia.

They found that the rate of patients who underwent a CPM increased from 10.5 percent in 2004 to 33.3 percent in 2012 among women between the ages of 20 and 44. In the 45 and older group, there was an increase from 3.6 percent to 10.4 percent.

The investigators speculate that more women are opting for this procedure because they fear developing a second breast cancer and want their breasts to be symmetrical after reconstructive surgery.

The increase was evident in all states, but it varied depending on the state. The rate of women between ages 20 and 44 who were treated in New Jersey rose from 14.9 percent in 2004 to 24.8 percent in 2012, but in Virginia it rose from 9.8 percent to 32.2 percent.

The rate of young women undergoing reconstructive surgery also increased in many states, but not to the same degree as CPM. The highest proportion of those women were clustered in several Northeastern states rather than the Midwestern region, which had the highest rate of CPM.

The investigators believe that more research needs to be done to study patient-, clinician- and health system-level factors, to better understand the reasons for temporal changes and regional variations in those who undergo CPM.

"It is very difficult to characterize the increase in preventive mastectomy as a positive or negative outcome at patient level because of personal preference, so long as the decision was made after thorough understanding of the benefit and risk of the treatment," said Jemal.

He recommends that surgeons and other health care professionals should educate their patients about the benefit, harm and cost of CPM to help them make informed decisions about their treatments.

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