NEW YORK (Reuters Health) - Factors other than medical history and risk may influence women with cancer in one breast to have both breasts removed even if it doesn't improve their odds of survival, suggests a new study.
Receiving genetic tests, advanced imaging and having a strong fear that cancer would develop in their second breasts were tied to an increased likelihood that women would choose to have a preventive double mastectomy, researchers found.
“Usually if something is not needed to be removed, it’s not removed,” said Sarah Hawley, from the University of Michigan Medical School in Ann Arbor, the study’s lead author.
The Society of Surgical Oncology suggests that preventive double mastectomy - also known as contralateral prophylactic mastectomy (CPM) - be considered for patients at an increased risk of cancer, such as those with genetic susceptibility or strong family history of cancer.
But the recommendation stops there because of a lack of evidence that removing the second breast will improve survival for women outside those categories.
Despite that guidance and research indicating that less than 10 percent of women with cancer in one breast meet one of those risk criteria, the rate of preventive double mastectomies has increased, Hawley's team writes in JAMA Surgery.
One study found the overall rate of preventive double mastectomy increased from about 2 percent of women with breast cancer in 1998 to about 4.5 percent in 2003.
The researchers analyzed data on 1,447 women who were diagnosed with breast cancer between 2005 and 2007 in the Los Angeles and Detroit areas to see which women chose double mastectomy and get a sense of why they did.
“We found that just under 20 percent of all women in our sample reported that they strongly considered having CPM,” Hawley said. “Ultimately, about 8 percent had the procedure.”
Less than a third of the women who had both breasts removed were at higher than average risk due to genetics or family history.
“There are a substantial number of women who get it in absence of clinical indications,” Hawley said.
They found, for example, that women who had a double mastectomy were 10 times as likely to have been tested for genetic susceptibility - regardless of the result - as women who had one breast removed, and 20 times more likely to have been tested as women who had breast-conserving surgery.
Women with a family history of breast cancer, those who received magnetic resonance imaging (MRI) when they were diagnosed and the highly educated were also more likely to get both breasts removed.
The researchers note that anxiety over the possibility that the cancer would return was an important factor in the women's choices, regardless of their actual risk of recurrence.
“Women who were very worried were very likely to get the procedure, compared to those who were less worried,” Hawley said.
She thinks that understanding what may influence women to choose a preventive double mastectomy could help doctors and researchers create educational and decision-making tools that better inform women about their risks and comfort them in their choices.
Women may have misunderstandings about their risks and an urge to do everything in their control to lessen the risk, said Dr. Ann Partridge of the Dana-Farber Cancer Institute in Boston.
For example, women may think the biggest risk is cancer spreading to their other breast, but the bigger risk is that it will spread to other parts of the body, Partridge, who co-wrote a commentary accompanying the new study, said.
“We don’t want women having regrets or complications that they do not need,” she said.
“If you’re not sure what to do, wait,” Partridge said. “You can always take the breast off, but you can’t put a natural breast back on.”