Universal BRCA mutation testing

besa

http://www.medpagetoday.com/Genetics/GeneticTestin...

Universal BRCA Testing Slammed as Too Costly, Inefficient

But BRCA1 discoverer disagrees....

MelissaDallas

If family history doesn't warrant it (with allowance for unknown history) I don't understand the benefit of universal testing. If the history of related cancer in a family isn't there the positive results are exceptionally low, almost infinetesimal

BarredOwl

Hi Besa:

Thanks for posting the link to this MedPage article. It highlights the debate in this area. It also contains a link to Dr. King's very interesting article, discussing her proposal for broader screening in the US population, and the differences between the Israeli population of her study and the more heterogenous US population.

http://jama.jamanetwork.com/article.aspx?articleid...

I have no view one way or the other. Genetic testing is a personal decision, with pros and cons, and in my personal opinion, is best made in consultation with a professional Genetic Counselor.

Melissa's comment re "with allowance for unknown history" is a very important one. I had the personal experience of an evolving family history, where suspicion was suddenly increased by new cancer diagnoses in successive generations. NCI PDQ states:

"The accuracy and completeness of family histories must be taken into account when they are used to assess risk. A reported family history may be erroneous, or a person may be unaware of relatives affected with cancer. In addition, small family sizes and premature deaths may limit the information obtained from a family history. Breast or ovarian cancer on the paternal side of the family usually involves more distant relatives than does breast or ovarian cancer on the maternal side, so information may be more difficult to obtain. . . Additional limitations of relying on family histories include adoption; families with a small number of women; limited access to family history information; and incidental removal of the uterus, ovaries, and/or fallopian tubes for noncancer indications. Family histories will evolve, therefore it is important to update family histories from both parents over time. (Refer to the Accuracy of the family historysection in the PDQ summary on Cancer Genetics Risk Assessment and Counseling for more information.)"

In this regard, Dr. King makes some interesting observations about the variability in practice in the assessment of family history citing a 2011 report:

"Population-based screening enables mutation carriers to be identified independent of physician referral or family involvement. This is important, because at present, there is marked variability in practice in following USPSTF guidelines. A recent survey revealed that only 19% of US primary care physicians accurately assessed family history for BRCA1/BRCA2 testing. In our study in Israel, only 35% of families with high incidence of breast or ovarian cancer had been previously referred for genetic counseling, despite common knowledge of the increased risk due to BRCA1 and BRCA2 in the Ashkenazi Jewish population and the availability of free testing and counseling in the Israeli health system. Population-based screening circumvents these barriers."

Regarding the estimated number of actionable mutations in the US population, she states:

"In the United States as a whole, the number of carriers of actionable mutations in BRCA1 and BRCA2 carriers is estimated to be between 1 in 300 and 1 in 500 women, or between 250 000 and 415 000 adult women for whom breast and ovarian cancer is both highly likely and potentially preventable."

I am not sure how the above estimate was arrived at (it would appear to include those with or without family history). Regarding those with less family history, the Israeli study surprisingly found:

"Notably, 50% of families found to harbor BRCA1 or BRCA2 mutations had no history of breast or ovarian cancer that would have triggered clinical attention."

BarredOwl