Randomised trial of population‐based BRCA testing in Ashkenazi Jews: long‐term secondary lifestyle behavioural outcomes
Abstract
Objective
Ashkenazi‐Jewish (AJ) population‐based BRCA testing is acceptable, cost‐effective and amplifies primary prevention for breast & ovarian cancer. However, data describing lifestyle impact are lacking. We report long‐term results of population‐based BRCA testing on lifestyle behaviour and cancer risk perception.
Design
Two‐arm randomised controlled trials (ISRCTN73338115, GCaPPS): (a) population‐screening (PS); (b) family history (FH)/clinical criteria testing.
Setting
North London AJ‐population.
Population/Sample
AJ women/men >18 years. Exclusions: prior BRCA testing or first‐degree relatives of BRCA‐carriers.
Methods
Participants were recruited through self‐referral. All participants received informed pre‐test genetic counselling. The intervention included genetic testing for three AJ BRCA‐mutations: 185delAG(c.68_69delAG), 5382insC(c.5266dupC) and 6174delT(c.5946delT). This was undertaken for all participants in the PS arm and participants fulfilling FH/clinical criteria in the FH arm. Patients filled out customised/validated questionnaires at baseline/1‐year/2‐year/3‐year follow‐ups. Generalised linear‐mixed models adjusted for covariates and appropriate contrast tests were used for between‐group/within‐group analysis of lifestyle and behavioural outcomes along with evaluating factors associated with these outcomes. Outcomes are adjusted for multiple testing (Bonferroni method), with P < 0.0039 considered significant.
Outcome measures
Lifestyle/behavioural outcomes at baseline/1‐year/2‐year/3‐year follow‐ups.
Results
1034 participants were randomised to PS (n = 530) or FH (n = 504) arms. No significant difference was identified between PS‐ and FH‐based BRCA testing approaches in terms of dietary fruit/vegetable/meat consumption, vitamin intake, alcohol quantity/ frequency, smoking behaviour (frequency/cessation), physical activity/exercise or routine breast mammogram screening behaviour, with outcomes not affected by BRCA test result. Cancer risk perception decreased with time following BRCA testing, with no difference between FH/PS approaches, and the perception of risk was lowest in BRCA‐negative participants. Men consumed fewer fruits/vegetables/vitamins and more meat/alcohol than women (P < 0.001).
Conclusion
Population‐based and FH‐based AJ BRCA testing have similar long‐term lifestyle impacts on smoking, alcohol, dietary fruit/vegetable/meat/vitamin, exercise, breast screening participation and reduced cancer risk perception.