How does aromatase inhibitor therapy work?

Aromatase is an enzyme that helps the body make oestrogen, especially after menopause. Medicines such as anastrozole and letrozole block this enzyme. They do not remove a tumour directly; instead, they reduce a growth signal for cancers whose cells carry hormone receptors. Treatment may be used after surgery, with other cancer care, or when disease has spread, depending on the treatment plan.

Lower oestrogen can also affect healthy tissues. Joint or muscle aches, hot flushes, tiredness, and changes in bone strength may occur. Your oncology team can review symptoms and consider bone health monitoring or supportive treatment when appropriate.

Take the medicine on the schedule prescribed and tell your team about every medicine, supplement, or herbal product you use. Do not stop it because of aches without discussing alternatives or symptom relief. Keep appointments so your team can review side effects, bone health, and whether the treatment remains suitable. Gentle movement, strength exercises suited to your health, and practical measures for hot flushes may help, but check before changing activity if you have bone problems.

Contact your cancer team promptly for severe or worsening pain, a new fall or suspected fracture, marked weakness, unusual swelling, or symptoms that make daily activities difficult. Seek urgent medical help for sudden chest pain, severe breathlessness, or one-sided weakness. These symptoms need assessment rather than being assumed to be a medicine side effect.

Ask which aromatase inhibitor is planned, how long you should take it, how bone health will be checked, and what options are available if joint symptoms interfere with everyday life.