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Study Finds Comprehensive Genetic Assessments Important for Women at High Risk For Breast Cancer (dateline December 18, 2001)

Some women who fear that they will develop breast cancer due to a strong family history of the disease or other factors choose to have their breasts removed to lower their cancer risk.

While prophylactic mastectomy (preventive breast removal) can significantly reduce the risk of breast cancer, a new study shows that many women make the decision to have the surgery out of fear. In fact, when study participants underwent comprehensive genetic assessments prior to surgery, many of the women changed their minds and decided not to have their breasts removed. The researchers say that genetic evaluation and counseling can be extremely beneficial to women at high risk of breast cancer to help them understand their true cancer risk and explore preventive options with knowledge medical professionals.

The research was conducted by Katherine T. Morris, MD, of the Oregon Health Sciences University in Portland, Oregon, and her colleagues. The researchers enrolled 60 women to undergo an assessment of their breast cancer risk based on their family histories. A total of 31 patients decided their risk of breast cancer was very high and considered have prophylactic mastectomies to reduce their breast cancer risk. However, Dr. Morris and her colleagues first had the women undergo genetic assessment and counseling sessions. During these sessions, the women underwent thorough genetic evaluations (including genetic testing) to understand their true risk of developing breast cancer. After these sessions, only 18 of the 31 women decided to still have the preventive surgery.

“Breast cancer risk estimation and genetic evaluation can be complex,” wrote Dr. Morris and her colleagues in the May 2001 issue of the American Journal of Surgery. “Comprehensive genetic risk assessment programs can play a significant role in the management of patients considering prophylactic surgery for perceived high risk.”

Approximately 5% to 10% of breast cancer and ovarian cancer cases result from the mutation of genes (called BRCA1 and BRCA2). BRCA gene testing is available for women at high risk of breast cancer, based on their family history of breast and/or ovarian cancer or other factors. Candidates for BRCA testing include those women with:

  • Breast cancer in two or more close relatives, such as a mother and two sisters
  • Early onset of breast cancer in family members, often before age 50
  • History of breast cancer in more than one generation
  • Cancer in both breasts in one or more family members
  • Frequent occurrence of ovarian cancer
  • One or more BRCA positive relatives
  • Eastern and Central European (Ashkenazi) Jewish ancestry, with a family history of breast and/or ovarian cancer (researchers have identified two types of BRCA1 mutations and one BRCA2 mutation that are especially prominent in this group)

As Dr. Morris’s study illustrates, knowing the results of breast cancer genetic testing can help women understand their true risk of developing the disease. This knowledge, in turn, helps women weigh preventive options based on their likelihood of getting breast cancer. However, knowing the results of genetic testing can also cause stress and worry for women who test positive or provide a false sense of security among women who test negative for BRCA gene mutations. Therefore, counseling by a genetic specialist is important in helping women understand the advantages and disadvantages of undergoing genetic testing as well as the significance of their test results.

Though the women in Dr. Morris’ study were considering prophylactic mastectomy to reduce their breast cancer, this is not the only preventive option available for high-risk women. Other options include close monitoring by physicians with frequent mammograms and clinical breast exams; taking the anti-estrogen drug tamoxifen; or participating in a clinical trial designed to find alternative methods of preventing breast cancer. In a very small percentage of cases, the preventive removal of the ovaries (oophorectomy) may be a viable option.

The take-home message of Dr. Morris’ study is that genetic counseling and testing can help high-risk women understand their individual cancer risk and make informed medical decisions, based on knowledge instead of fear.

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