Procedure
breast cancer single-nucleotide polymorphisms, breast cancer
RECRUITMENT, BREAST, BREAST CANCER
All women were invited to have a mammogram by the NHSBSP during the recruitment period. During the COVID-19 pandemic, the NHSBSP programme changed the breast screening invitation process to open-invite letters, and this continued for the duration of this study rather than reverting back to the previous usual practice of sending pre-allocated appointments.Women offered BC-Predict were sent an additional invitation letter one to two working days after their breast screening invitation letter was sent. The BC-Predict invitation letter was sent along with the participant information sheet and instructions directing prospective participants to the online risk assessment platform. Following written informed consent, risk assessment was based on self-report questions completed by participants using the online risk assessment platform. Breast density estimates were automatically derived from mammography for the majority of women who agreed for images to be used. For some women, risk assessment also incorporated information from breast cancer single-nucleotide polymorphisms (SNPs), derived from DNA contained in saliva samples primarily collected via sampling kits sent and returned by post to the research office.Women in the BC-Predict arm who took up the offer of BC-Predict and who received a clear mammogram result were sent a letter in the post providing them with their 10-year breast cancer risk ~6–8 weeks after their mammogram. The risk feedback letter informed women that they are at “high” (≥8% 10-year risk), “above average (moderate)” (≥5% but <8% 10-year risk), “average” (≥2% but <5% 10-year risk), or “below average” risk (<2% 10-year risk). Each letter explained how the risk estimates were derived, and the implications of these along with a leaflet providing additional detail on breast cancer risk factors, signs and symptoms of breast cancer and how risk might be managed. Full details of the development and refinement of risk letters and accompanying leaflets are described elsewhere [From March 2021, the “below average” label was replaced with “low”, and women who received this result were also told that whether to extend the screening interval for women at this level of risk was being considered by the NHSBSP (this change was due to a planned within-study comparison of two ways of communicating information about below average/low risk that did not yield sufficient numbers of women for analyses to be worthwhile).Women were asked to complete questionnaires at baseline, 3 months and 6 months after their initial mammogram appointment date, after providing explicit consent. For women in both BC-Predict and standard NHSBSP groups, the invitation to complete the questionnaire was sent approximately 7 days after their first offered mammogram appointment. The invite letter and patient information sheet provided interested women with instructions to complete an online consent form and questionnaire using a unique study identification number on SmartSurvey (A fuller description of procedures for the larger PROCAS2 study and developmental work, which underpinned the refinement of procedures, technical processes and patient-facing material, is provided elsewhere [