What hormone therapy is
Oestrogen and progesterone can drive the growth of some breast cancers; testosterone drives most prostate cancers. Hormone therapy either lowers the amount of these hormones in the body or blocks the cancer cells' ability to respond to them. It is a systemic treatment — it reaches the whole body — and is prescribed and monitored by medical oncologists and, for prostate cancer, often together with urologists.
It is different from hormone replacement therapy used for menopause symptoms, which is generally avoided in hormone-sensitive cancers.
When hormone therapy is considered
Breast cancer. Only for cancers that test positive for oestrogen and/or progesterone receptors (ER/PR) on the biopsy — roughly two out of three breast cancers. It may be used after surgery for several years to reduce the risk of recurrence, before surgery in some cases, or as the main treatment for advanced ER-positive disease, often combined with newer targeted drugs. The choice of medicine depends on whether you are before or after menopause.
Prostate cancer. Lowering testosterone (androgen deprivation) is a mainstay for cancer that has spread and is also used with radiation for higher-risk localised disease. Newer hormonal agents are added in specific situations.
Hormone therapy is also used in some endometrial (uterine) cancers and a few other tumours.
What treatment involves
Most breast-cancer endocrine therapy is a daily tablet taken for five to ten years; some patients also have injections that switch off the ovaries. Prostate-cancer hormone therapy is usually an injection every one to six months, with or without daily tablets. Blood tests and check-ups monitor response and side effects; bone health is checked because long-term hormone suppression can weaken bones.
Side effects
Menopause-like symptoms (hot flushes, sweats, vaginal dryness, mood changes), joint aches, tiredness, loss of libido, weight change, and over time reduced bone density are common with breast-cancer endocrine therapy; some drugs slightly raise the risk of blood clots or uterine changes and are monitored accordingly. In prostate cancer, hot flushes, fatigue, loss of muscle, weight gain, reduced libido and erectile changes, and effects on bone and metabolic health are the main issues. Many of these are treatable, and stopping early because of unmanaged side effects is a common, avoidable reason for treatment failing — tell your team.
Questions worth asking
- What did my receptor tests show, and does that make hormone therapy suitable for me?
- Is this instead of, or as well as, chemotherapy or radiation — and why?
- How long will I take it, and what happens if I stop early?
- Which side effects can be treated, and how will my bone health be monitored?
- If I am hoping to have children, how does this affect timing and fertility options?
Preparing for your consultation
Bring the biopsy report showing receptor results (ER, PR, HER2 for breast cancer; Gleason score and PSA for prostate cancer), scans, and your medicine list. Note your menopausal status or, for men, any heart, bone or diabetes history — these shape the choice of drug.