Preventative therapy for breast cancer: a clinical experience.

Background: Breast Cancer incidence in the UK is estimated to rise to 71,000 per year by 2035. Preventative strategies could significantly reduce this. Preventative therapy reduces women's risk of oestrogen receptor positive breast cancer, but uptake remains low. Having established a preventative therapy clinic as part of a wider breast cancer prevention project, we explored qualitative data to inform future preventative efforts.

Method: Women aged 30 to 60 who had benign diagnoses at a symptomatic breast clinic or were under mammographic surveillance in the moderate risk family history clinic were invited to participate in the study. Those who expressed an interest and completed an initial questionnaire had their breast cancer risk calculated using the IBIS risk calculator. Those at increased risk were invited to a consultation about preventative therapy.

Results: 182 women were identified as increased risk (≥ 17% lifetime or ≥ 3% 10-year risk NICE guidelines: Familial breast cancer: classification, care and managing breast cancer and related risks in people with a family history of breast cancer, 20131) of whom 91 women (50%) would not have been identified by family history criteria alone. 96% attended a risk/prevention consultation and all eligible women accepted screening mammography but only 14 (8%) women requested a preventative therapy prescription during the duration of the study. Reluctance to take medication and inconvenient time of life were common reasons for declining preventative therapy. Despite this, the majority were grateful for breast cancer risk and prevention information.

Conclusions: Women at increased risk of breast cancer accept additional screening but are reluctant to take preventative therapy. This suggests that stratified screening methods using risk calculations would have high uptake. Raising awareness of preventative therapy is important and the breast cancer community has yet to find the optimum timing and formula for discussing it and must accept women's informed preferences above artificial targets.

Registration Numbers: The PIONEER study was granted Health Research Authority (HRA) ethical approval by the Westminster Ethics Committee. IRAS project ID 265619, ClinicalTrials.gov Identifier: NCT04574063. Recruitment began in September 2020 and was completed in October 2021.