External radiotherapy for prostate cancer

External radiotherapy treatment uses a high dose of radiation just to the area of the prostate gland. You can have this treatment if your prostate cancer is between stage T1 and T3. This means that the cancer can have spread through the covering of the prostate gland (the capsule). But it must not have spread any further. If it has spread further, this treatment is not likely to cure it. And because of the side effects, it may not be the best treatment for you.

External radiotherapy treatment can be given in different ways, but it is usually given

• In 30 to 35 treatment doses called fractions
• Once a day, for 5 days each week (from Monday to Friday)
• For about 6 to 7 weeks

Your doctor will make sure the whole of your prostate gland is treated as well as an area of 1 to 2 centimetres around it. This is to make sure that any cancer cells a little way away from the main tumour are treated. These cells are called microscopic spread. They are too small to be seen on scans, but if they are not treated the prostate cancer is more likely to come back in the future.

UK Prostate Link can direct you to information about external radiotherapy treatment for prostate cancer.

With conformal radiotherapy, a computer is used to direct the radiotherapy beams to a more exact shape of your prostate. The idea is to cut down the amount of healthy body tissue that receives radiation. This way of giving radiotherapy can reduce side effects to the bladder and the bowel. In February 2008, the National Institute for Health and Clinical Excellence (NICE) published a manual on improving outcomes for prostate cancer. They say that conformal radiotherapy is the best way to give external radiotherapy for prostate cancer.

Doctors are also looking at a new type of conformal radiotherapy called intensity modulated radiotherapy (IMRT). IMRT can shape the radiotherapy beams even more exactly to the cancer and vary the dose across the area of the tumour. This can reduce the side effects. There is information about research into IMRT in the prostate cancer research section.

You will probably have some side effects from radiotherapy treatment. The most common ones are

• An inflamed bladder, making you want to pass urine very often
• An inflamed bowel, causing diarrhoea
• Tiredness
• Sore skin in the area of the prostate
• Loss of pubic hair

Your side effects may last for several weeks after your treatment has finished. Tiredness can last for some months afterwards. There is detailed information about coping with side effects in this section.

External radiotherapy can have side effects that last for longer than a few weeks. For most men, these symptoms settle down gradually, but for some they are permanent. Possible permanent side effects are

• Bowel problems
• Problems getting an erection (impotence)
• Problems passing urine

There are two types of bowel problems you may have.  Proctitis is a straining feeling in the back passage. You are less likely to get this effect if you have had conformal radiotherapy rather than conventional types of external radiotherapy. Some men also develop problems with frequent, loose bowel movements.  

Not being able to get an erection is a permanent side effect for up to 70 out of every 100 men treated with radiotherapy alone (70%). If you are having hormone treatment as well as radiotherapy, the risk of erection problems is higher.

You may also have problems with passing urine. Some men develop a narrowing of the tube that carries urine from the bladder.

Unfortunately, your doctor cannot tell before you are treated whether you are likely to have permanent side effects. There is detailed information about radiotherapy side effects in this section.

External beam radiotherapy for prostate cancer can also increase the risk of developing rectal cancer but the risk is still small.