Σάββατο, 1 Απριλίου 2017

USE OF BRCA TESTING INCREASING IN LOW RISK PATIENTS

Although the number of women referred for genetic counseling and BRCA mutation testing in the United States has skyrocketed in the past decade, the vast majority of women at high risk for breast and ovarian cancer are not being tested, a large, retrospective cohort study now reveals.
The study, which examined private insurance claims for BRCAmutation testing between 2004 and 2014, shows that testing increased from 24.3% to 61.5% (< .001).
However, only 17.6% of women aged 20 to 40 years who were tested had been previously diagnosed with breast or ovarian cancer, whereas 41.7% were "unaffected" by a history of cancer and did not meet the recommended guidelines for screening, says a research team led by Fangjian Guo, MD, PhD, from the University of Texas Medical Branch in Galveston.
"The role of BRCA testing in the US has gradually shifted over the past decade from being used primarily in cancer patients to being used in unaffected women," the team comments.
The findings come from report published online March 22 in the American Journal of Cancer Prevention.
From 2004 to 2014, the proportion of BRCA testing carried out in unaffected women increased by more than 50%. This increase was seen in women of all age groups with the exception of women aged 51 to 65, irrespective of region of residence and whethere there was family history of breast or ovarian cancer.
By 2014, women aged 20 to 40 years who did not have a previous history of breast or ovarian cancer accounted for more than 80% of BRCA testing in unaffected women
This trend has resulted in "missed opportunities for cancer prevention," the researchers point out, and they note that it has been estimated that more than 90% of the 220,000 BRCA mutation carriers in the United States remain unidentified.
"BRCA testing has not been well utilized among US women, and the majority of at-risk women do not get referrals for genetic counseling or testing," they say.
Many far-ranging factors are involved. Recommendations for screening that do not go far enough and lack of awareness on the part of primary care clinicians may be two of them, say Dr Guo and colleagues.
In women with early-onset breast or ovarian cancer, BRCA testing can identify those with high-risk mutations and point the way to specific treatment options, they note. It can also identify high-risk mutation carriers for early and intensified screening or even chemotherapy and prophylactic surgery.
Although current screening guidelines set by the US Preventive Services Task Force and the National Comprehensive Cancer Network recommend BRCA testing based on a personal or family history of cancer, a large proportion of high-risk mutation carriers are missed, Dr Guo told Medscape Medical News. "It is hard to tell who should or should not get BRCA testing beyond those who fall under the current guidelines, because we still do not know how to efficiently identify most of the mutation carriers," he said.
The estimated prevalence of potentially harmful BRCA mutations is 6.0% in women with a diagnosis of cancer before the age of 40 years, 2.1% in Ashkenazi Jewish women, and 0.2% to 0.3% among the general population, the researchers note.
Large studies in Canada, Israel, and the United Kingdom indicate that more than half of Ashkenazi women who carry the mutation do not qualify for genetic testing on the basis of family history, they point out. "Most young women with breast cancer do not have a family history of breast or ovarian cancer or Ashkenazi Jewish ancestry, and will not be eligible to undergo BRCA mutation testing before a cancer diagnosis."
Advances in next-generation sequencing have dramatically reduced costs for genetic testing, just as years of "massive and intensive" marketing for BRCA testing have "loosened" screening criteria and increased anxiety about the implications of not testing, the researchers say. As a result, more patients are demanding testing, even when they have to refer themselves and pay out of pocket.
Although primary care physicians may have reason to feel frustrated about the lack of clear guidance on BRCA mutation testing, they should still "be well prepared to discuss the pros and cons of genetic testing to help women make informed decisions," Dr Guo told Medscape Medical News.
However, evidence from a 2007 survey of primary care physicians indicates this may not always be the case, the researchers point out. Only 19% of clinicians were able to correctly identify risk patterns on the basis of family history, and 45% chose one or more low-risk scenarios as indications for BRCA testing. In another survey of 3000 US primary care providers, one third said they would consider referring women for genetic counseling and testing even if they were not at high risk.
More studies are needed to better identify mutation carriers, the researchers emphasize. "Current guidelines and clinical practice fail to efficiently identify women who carry harmful BRCA mutations. Effective testing strategies need to be identified that promote equitable distribution and rational use of BRCA testing and maximize the detection of mutation carriers."
The researchers note a number of study limitations, including the fact that the results may not be applicable to uninsured women or those covered by Medicaid. They also point out that 48.7% of the female claimants lived in the southern United States.
Funding for this research was provided by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Office of Research on Women's Health of the National Institutes of Health. The authors have disclosed no significant financial relationships.
Am J Prev Med. Published online March 22, 2017. Full text

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