Women with a mutation in BRCA 1 or BRCA2 who develop breast cancer can have breast-sparing surgery but should consider hormone therapy to prevent recurrence, according to an article in the June 1 issue of Journal of Clinical Oncology.

Because of both initial increased risk for breast cancer and increased risk for recurrence or a second primary tumor, women who carry a mutation on the BRCA1 or BRCA2 gene are at an increased risk of breast cancer compared to women without the mutation. And have been unsure whether they can safely undergo breast-conserving surgery instead of mastectomy.

The international study involved 160 patients in the USA, Canada, and Israel who had early breast cancer and BRCA1 or BRCA2 gene mutations. The women were treated with lumpectomy, followed by radiation therapy. These women were compared with 445 similar women who were treated for breast cancer but did not carry the genetic mutations.

After 15 years, both groups had similar rates of recurrence in the same breast. However, women with BRCA mutations who also underwent oophorectomy were less likely to have a recurrence. Similarly, tamoxifen dropped the risk of same-breast recurrence for mutation carriers by 58 percent.

Women with genetic mutations had a significantly greater risk of developing breast cancer in the opposite breast than did control women. After 15 years, 45 percent of women with mutations who had not undergone oophorectomy developed breast cancer in the other breast compared with only 9 percent of women without mutation.

Women with the mutation who took tamoxifen had a 69 percent reduction in breast cancer in the opposite breast. Among women who did not undergo oophorectomy, tamoxifen made a significant difference: 6 percent of those taking tamoxifen had a second cancer in the opposite breast after 15 years compared with 54 percent of those who did not take tamoxifen.

“For women with early stage breast cancer who are BRCA1 or BRCA2 carriers, our 10-year data suggest that oophorectomy or tamoxifen in women treated with breast conservation and radiation therapy help to reduce the risk of recurrences and new primary cancers in the treated breast to levels comparable to those observed in women with early stage breast cancer who are not BRCA1 or BRCA2 carriers,” said lead study author Lori J. Pierce, MD, professor of radiation oncology at University of Massachusetts Medical School.

“However, carriers must understand that the risk of breast cancer in the opposite breast still remained significantly greater than in women without a mutation. Thus, it is very important that women who choose breast preservation discuss with their doctors surveillance strategies not only of the involved breast but also in the opposite breast,” she added.

Many women with the genetic mutations will have both their breasts removed before cancer develops as a preventive strategy. After breast cancer develops, bilateral mastectomy reduces the risk of it recurring by at least 90 percent. But studies have shown approximately the same number of breast cancer patients with the mutations choose mastectomy and breast conservation, suggesting considerable interest in breast conservation among this group of women.

“We need to look to hormonal therapies that may lead to greater risk reductions than tamoxifen. For example, recent studies suggest comparable risk reductions with raloxifene and tamoxifen but fewer side effects with raloxifene. Studies are needed to assess the effect drugs such as raloxifene or aromatase inhibitors have in preventing second tumors in breast cancer mutation carriers,” Pierce concluded.