Receive our quarterly lifestyle research updates

Your doctor has recommended a medication called Stilboestrol as treatment for your prostate cancer. This page provides extra information about your medicine, summarises possible side effects and methods to alleviate them.

What is Stilboestrol? An oral tablet taken at a dose of 3-5mg once a day, belongs to group of medicines called man made oestrogens (the female hormone). They are used to treat male patients with prostate cancer. Many people like to take it at the same time each day – the actual time does not matter. Some prefer to take it with food some after meals  - try to find a convenient time and stick to it as its easier to remember to take the tablets in the long term.

If you forget to take your tablet don’t panic – levels of the drug in your blood will not change very much –   not to miss more than one or two tablets in a row. Remember to get a new prescription a couple of weeks before you run out of the tablets and make sure you have plenty for holidays etc.

How do they work? Some tumours such as prostate cancer are stimulated by the bodies own male hormone (Testosterone). Stopping the bodies testosterone reaching the tumour can cause the cancer cells to stop growing and in some cases shrivel up and die completely (self destruct - apoptosis).  Stilboestrol works by fooling the signal pathway between the brain  and the testes by increasing the blood levels of a chemical which looks like the female hormone oestrogen. In turn the brain thinks the testies are producing too many sex hormones including testosterone and as a consequence switches off the driving signal by itself - this results in a marked reduction in the blood level of testosterone.

How will I & the doctor know they are working? In most cases there is something the doctor can measure. This may be how you feel, a symptom related to your cancer, something which can be felt on examination (e.g. a lump or size of prostate),   something seen on a scan or xray. or a blood test called PSA, (the level of which will get lower if you are responding).

Possible side effects All medications have side effects. These can effect some people more than others. It its hard to predict the level and type of side effect for each individual. Listed below are an overview of the more common side effects you may encounter, however, you may experience none, all, or only a few of these. You may also have a rare side effect not listed here - If you become aware of any other side effects, please report them to your clinic.

If side effects are severe, you may have to stop taking the drug and a different hormonal drug may be prescribed.

  • Ankle swelling  If prone to this, Stilboestrol  can make it worse. In severe cases this can lead to fluid retention and a strain on the heart and an increased risk of angina and heart failure.
  • Increase risk of blood clots - in the veins in the legs rarely these can break off to the lung (pulmonary embolus) - Often Stilboestrol is given with a low dose of warfarin to thin the blood.
  • Breast tenderness and swelling  Often the nipples in men become tender and begin to swell. This can often be prevented by given a small dose of radiotherapy to the breast buds
  • Sex drive (libido) Stilboestrol has a  significant impact on the sex drive and impairs the ability to have erections.
  • Lethargy It is possible to have mild lethargy with Stilboestrol- it is most severe at the beginning but can wear off over time. See coping with lethargy . In some men it occasionally has the opposite effect and they experience wakefulness.
  • Nausea and indigestion Feelings of mild sickness (nausea) and indigestion can occur but t usually wears off after a few weeks. see diet and indigestion
  • Weight gain Weight gain can be a side effect of Stilboestrol and this is sometimes due to water retention but at other times a consequence of a eating more either due to a increased appetite or mild nausea - "to settle the stomach" . See coping with weight gain.

Less common side effects include:-

  • Allergic reactions – this may include skin rashes
  • Temporary thinning of the hair.
  • Swelling and tenderness of the breasts
  • Headaches – some people affected by migraine have noticed a change in the pattern of their headaches

Other issues There is no interaction between Stilboestrol and moderate amounts of alcohol.  It does not usually affect your ability to drive.       

Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.

Lifestyle tips Aide gut health Micronutrient tests Protect nails
Amazing polyphenols