What Are the Benefits and Harms of Risk Stratified Screening as Part of the NHS Breast Screening Programme: Study Protocol for a Multi-site Non-randomised Comparison of BC-Predict Versus Usual Screening

In principle, risk-stratification as a routine part of the NHS breast screening programme (NHS-BSP) should produce a better balance of benefits and harms. The main benefit is the offer of NICE (National Institute of Health and Care Excellence) approved more frequent screening and/ or chemoprevention to be realised for women who are at increased risk, but are unaware of this. The invesigators have developed BC-Predict, which is offered to women when invited to NHS-BSP and collects information on risk factors (self-reported information on family history and hormone-related factors, mammographic density and in a sub-sample, Single Nucleotide Polymorphisms). BC-Predict then produces risk feedback letters, and invites women at moderate or high risk to have discussion of prevention and early detection options at Family History, Risk and Prevention Clinics. Key objectives of the present research are to quantify important potential benefits and harms, and to identify the key drivers of the relative cost-effectiveness of embedding BC-Predict into NHS-BSP.

A non-randomised fully counterbalanced study design will be used, to include equal numbers of participants from five screening sites who will be offered NHS-BSP and BC-Predict. Specifically, in the initial 8-month time period, women eligible for NHS-BSP in three screening sites will be offered BC-Predict, whilst women in two screening sites are offered usual NHS-BSP. In the following 8-month time period the study sites switch their offers. In total 16000 women will be invited to BC-Predict, and compared with 16000 women offered standard NHS-BSP. Key potential benefits including uptake of BC-Predict, risk consultations, chemoprevention and additional screening will be obtained from NHS-BSP and Family History, Risk and Prevention Clinic records for both groups. Key potential harms such as increased anxiety will be obtained via self-report questionnaires. Health economic analyses will identify the key uncertainties underpinning the relative cost-effectiveness of embedding BC-Predict into NHS-BSP.