According to the Preventive Services Task Force in the U.S., routine testing for mutations in the BRCA1 and BRCA2 genes, which have been linked to breast and ovarian cancer, are not advised unless women have a family history of the disease.
Apparently in women without a family history, the residual harm from counseling or genetic testing is likely to outweigh any benefits.
They panel suggests that genetic testing should be restricted to women with a positive, personal or family history, only after they have undergone genetic counseling. Genetic counseling will then allow informed decision-making about testing and preventative treatment.
The recommendations, from Dr. Heidi D. Nelson, at Oregon Health and Science University in Portland, and her colleagues, set out the family history patterns that would warrant genetic counseling, they include:
- two first-degree relatives with breast cancer, one of whom was diagnosed at age 50 or younger;
- three or more first- or second-degree relatives with breast cancer;
- breast and ovarian cancer among first- and second-degree relatives;
- one first-degree relative with cancer in both breasts;
- two or more first- or second-degree relatives with ovarian cancer;
- one first- or second-degree relative with breast and ovarian cancer;
- a history of breast cancer in a male relative;
- a woman of Ashkenazi Jewish descent with any first- or second-degree relative with breast or ovarian cancer.
Nelson's team say that "risk assessment, genetic counseling, and mutation testing did not cause adverse psychological outcomes, and counseling improved distress and risk perception in the highly selected populations studied."
Risk assessment includes information about various options for at-risk women, such as studies which have shown greatly reduced risk of cancer after preemptive mastectomy and ovary removal.
However, the researchers point out that surgical complications are common and there are no reports regarding reductions in mortality or improvements in quality of life after prophylactic surgery.
Similarly, there are pros and cons to tamoxifen therapy.
Studies revealed reduced risk of certain types of breast cancer, but these benefits were associated with increased risk of blood-clot complications and endometrial cancer.
Dr. Wylie Burke, from the University of Washington in Seattle, says that the recommendations will provide invaluable help to doctors seeking to help patients" who are considering BRCA testing.
The report is published in the Annals of Internal Medicine, September 6, 2005.