Genetic testing for BRCA1: effects of a randomised study of knowledge provision on interest in testing and long term test uptake; implications for the NICE guidelines.

Introduction: Interest in searching for mutations in BRCA1 and BRCA2 is high. Knowledge regarding these genes and the advantages and limitations of genetic testing is limited. It is unknown whether increasing knowledge about breast cancer genetic testing alters interest in testing.

Methods: Three hundred and seventy nine women (260 with a family history of breast cancer; 119 with breast cancer) from The Royal Marsden NHS Foundation Trust were randomised to receive or not receive written educational information on cancer genetics. A questionnaire was completed assessing interest in BRCA1 testing and knowledge on breast cancer genetics and screening. Actual uptake of BRCA1 testing is reported with a six year follow-up.

Results: Eighty nine percent of women at risk of breast cancer and 76% of women with breast cancer were interested in BRCA1 testing (P < 0.0001). Provision of educational information did not affect level of interest. Knowledge about breast cancer susceptibility genes was poor. According to the NICE guidelines regarding eligibility for BRCA1 and BRCA2 testing, the families of 66% of the at risk group and 13% of the women with breast cancer would be eligible for testing (probability of BRCA1 mutation >or=20%). Within six years of randomisation, genetic testing was actually undertaken on 12 women, only 10 of whom would now be eligible, on the NICE guidelines.

Conclusions: There is strong interest in BRCA1 testing. Despite considerable ignorance of factors affecting the inheritance of breast cancer, education neither reduced nor increased interest to undergo testing. The NICE guidelines successfully triage those with a high breast cancer risk to be managed in cancer genetics clinics.