Synopsis
Select endocrine anticancer treatment by hormone dependence and disease setting, monitor response and adherence, and prevent thrombotic, skeletal, metabolic, cardiovascular and reproductive harm.
- Endocrine therapy deprives a hormone-dependent tumour of ligand or blocks its receptor; it is central to many breast and prostate cancer pathways.
- Treatment is selected by receptor or disease biology, menopausal or gonadal status, stage, prior exposure, comorbidity and treatment intent.
- Breast strategies include oestrogen-receptor modulation, aromatase inhibition, oestrogen-receptor degradation and ovarian suppression in defined combinations.
- Prostate strategies reduce androgen production or receptor signalling; some agents cause an initial testosterone surge and need pathway-specific flare protection.
- Endocrine treatment is often taken for months or years, making adherence, interactions and cumulative quality-of-life effects decisive.
- Bone loss, vasomotor symptoms, sexual dysfunction, infertility, metabolic change and cardiovascular risk require proactive discussion and prevention.
- Tamoxifen-associated thrombosis and endometrial symptoms, aromatase-inhibitor bone loss, and androgen-deprivation metabolic and skeletal harms differ and must not be conflated.
- New bleeding, chest pain, unilateral swelling, neurological deficit or severe mood change requires prompt assessment rather than routine side-effect reassurance.
Key red flags
New unilateral swelling, chest pain, breathlessness or neurological deficit during selective oestrogen-receptor modulation needs urgent thrombosis assessment.
Investigation priorities
Confirm that endocrine treatment matches the cancer biology.
Management branches
Hormone-sensitive breast, prostate or another cancer is confirmed.
- Define stage, intent, receptor biology, menopausal or gonadal status, prior treatment and important vascular or skeletal comorbidity.
- Choose the current tumour-specific first-line endocrine option or combination and explain expected duration, onset and alternatives.
- Address fertility, contraception, sexual health, bone and cardiometabolic risk before treatment begins.
Key medicines
Tamoxifen20 mg orally once daily for hormone-receptor-positive breast cancer; duration and any extension are set by the disease stage, menopausal status, recurrence risk and current breast protocol.Counsel about venous thromboembolism, vasomotor symptoms and endometrial pathology; investigate abnormal vaginal bleeding and review pregnancy risk, ocular symptoms and strong CYP2D6 inhibitors.
Letrozole2.5 mg orally once daily in an indicated postmenopausal breast-cancer setting, or only with confirmed ongoing ovarian suppression when used before natural menopause; follow the tumour protocol for duration and sequencing.Do not use an aromatase inhibitor alone when ovarian function persists. Assess bone density and fracture risk, lipids, arthralgia, adherence and signs of ovarian escape during pharmacological suppression.