Approximately 70% of women who have both breasts removed following a breast cancer diagnosis do so despite a very low risk of facing cancer in the healthy breast, new research has found.
Recent studies have shown an increase in women with breast cancer choosing this more aggressive surgery, called contralateral prophylactic mastectomy (CPM), which raises the question of potential overtreatment among these patients.
The study authors looked at 1,447 women who had been treated for breast cancer and who had not had a recurrence. They found that 8% of women had a double mastectomy, and that 18% considered having one. Their results appeared in JAMA Surgery (2014; doi:10.1001/jamasurg.2013.5689).
Many women with cancer in one breast consider, and eventually undergo, CPM to remove both breasts, although few of them have a clinically significant risk of developing cancer in both breasts.
Overall, about three-quarters of patients reported being very worried about their cancer recurring. Those who chose to have both breasts removed were significantly more likely to express concern about recurrence. But, a diagnosis of breast cancer in one breast does not increase the likelihood of breast cancer recurring in the other breast for most women.
“Women appear to be using worry over cancer recurrence to choose contralateral prophylactic mastectomy. This does not make sense, because having a nonaffected breast removed will not reduce the risk of recurrence in the affected breast,” said Sarah Hawley, PhD, associate professor of internal medicine at the University of Michigan Comprehensive Cancer Center in Ann Arbor.
In addition to asking about the type of treatment, researchers asked about clinical indications for double mastectomy, including the patients’ family history of breast and ovarian cancer and the results of any genetic testing.
Women with a family history of breast or ovarian cancer or with a positive genetic test for mutations in the BRCA1 or BRCA2 gene may be advised to consider having both breasts removed, because they are at high risk of a new cancer developing in the other breast. This represents about 10% of all women with breast cancer. Women without these indications are very unlikely to develop a second cancer in the healthy breast.
The study found that among women receiving a double mastectomy, nearly 70% did not have either a family history or positive genetic test. Many of these women were candidates for breast-conserving lumpectomy.
“For women who do not have a strong family history or a genetic finding, we would argue it’s probably not appropriate to get the unaffected breast removed,” said Hawley.
A double mastectomy is a bigger operation that is associated with more complications and a more difficult recovery. In addition, most women went on to have breast reconstruction as well. Women might also still need to undergo chemotherapy or radiation therapy after their surgery—treatments that are known to reduce the risk of cancer recurring—which could delay their recovery further.
The study also found that women with higher education levels and women who had undergone an MRI test before surgery were more likely to choose double mastectomy. Concern about recurrence was one of the biggest factors driving the decision to have this surgery.