When is CDK4/6 inhibitor therapy recommended for hormone receptor-positive breast cancer?

CDK4/6 inhibitors slow signals that help breast cancer cells divide. They are usually taken alongside endocrine treatment, which reduces the effect of oestrogen or other hormones on hormone-sensitive cells. The choice depends on whether treatment is intended after surgery to reduce recurrence risk or to control advanced disease. Your oncology team considers tumour features, previous treatment, general health, blood counts, liver function and possible medicine interactions.

Ask whether your pathology shows hormone receptor positivity and whether the cancer is early, recurrent or metastatic. Discuss the proposed medicine, dosing schedule, monitoring plan and how it fits with surgery, radiotherapy or other systemic treatment. Blood tests may be needed during therapy because these medicines can affect blood-cell counts and liver function. Report new symptoms rather than stopping treatment on your own; dose changes or a pause may manage side effects.

Contact your cancer team promptly for fever, chills, unusual bruising or bleeding, severe weakness, yellowing of the skin, dark urine, persistent diarrhoea or breathlessness. Seek urgent medical help for severe breathing difficulty, fainting or signs of a serious infection. The exact advice can differ by medicine, so keep the treatment contact number available.

Which CDK4/6 inhibitor suits my cancer and why? What benefit is expected from adding it to hormone therapy? Which blood tests or heart checks will I need? Which medicines, supplements or foods should I avoid? How will we decide whether treatment is working?