Why is tamoxifen used in risk-reducing endocrine therapy?

Risk-reducing endocrine therapy is considered for some people whose future breast cancer risk is higher because of personal history, breast findings, family history or inherited factors. A clinician first reviews the reason for increased risk and whether the likely benefit of hormone blocking fits your health and preferences.

Tamoxifen acts on oestrogen receptors in breast tissue. It does not remove an existing tumour and does not prevent every type of breast cancer. Risk assessment, breast screening and healthy-living advice remain part of care even when tamoxifen is chosen.

Ask your clinician to explain your individual risk, the expected reduction in risk in plain language, other prevention options and how long treatment would be considered. Share your medical history, medicines, clotting problems, menstrual or reproductive plans and any history of abnormal vaginal bleeding.

Take tamoxifen only as directed and report side effects rather than silently stopping. Hot flushes, sweating, mood changes, vaginal symptoms or menstrual changes may occur. Continue recommended breast checks and attend planned reviews so your decision can be revisited if your circumstances change.

Tell your care team promptly about unexpected vaginal bleeding, new breast symptoms, persistent leg swelling or pain, or changes in vision. Seek urgent care for sudden chest pain, difficulty breathing, coughing blood, or sudden weakness or speech difficulty. Contact the team promptly if you become pregnant or are planning pregnancy.

Ask what makes your risk higher, whether your likely future cancers are hormone-sensitive, how tamoxifen compares with other risk-reduction choices, what side effects matter most for you, and how screening will continue. Ask which medicines, supplements and contraceptive options are compatible with treatment.