What should you know about tamoxifen endocrine therapy?

Tamoxifen attaches to oestrogen receptors, which are docking points used by some breast cancer cells. This can reduce oestrogen signalling to receptor-positive cancer cells. It may be used after initial treatment, alongside other care, or to reduce the chance of cancer developing in a person with particular risk factors. The reason for treatment depends on your diagnosis, pathology results, menopausal status, and previous therapies.

Tamoxifen is different from chemotherapy. It works through hormone signalling rather than directly targeting rapidly dividing cells. Hot flushes, night sweats, vaginal symptoms, mood changes, and tiredness can occur, although experiences vary. Tell the team about troublesome effects because some can be managed or may have another cause.

Take each dose exactly as prescribed and keep a routine that helps you remember it. Do not double a missed dose unless your pharmacist or oncology team gives that instruction. Give the team a complete list of medicines, supplements, and herbal products; some treatments can alter how tamoxifen is processed. Keep scheduled reviews so symptoms, medicines, and the ongoing purpose of endocrine therapy can be assessed.

If you have a uterus, ask how any unexpected vaginal bleeding should be assessed. Tamoxifen can affect the lining of the womb, so bleeding after menopause deserves prompt medical attention. Do not stop treatment because of a side effect without discussing an alternative plan.

Seek urgent medical help for sudden chest pain, difficulty breathing, coughing blood, or one-sided leg swelling and pain. These can signal a blood clot. Contact your cancer team promptly for unusual vaginal bleeding, severe headache, sudden weakness, vision changes, or a new concerning symptom. A symptom does not by itself show that cancer has returned; the assessment determines the cause.

Ask which cancer feature makes tamoxifen appropriate, how long the planned course is, which effects should be reported, and whether any current medicine needs review. Ask what to do after a missed dose and how follow-up checks will be arranged.