Most men would obviously prefer to try some form of cancer radiation therapy than to undergo radical, invasive cancer surgery - a prostatectomy, possibly radical perineal prostatectomy, whereby the entire prostate is removed through the space between the anus and the penis - the perineum.

The treatment of prostate cancer depends largely on whether they are dealing with advanced prostate cancer or not and whether the patient's in good health otherwise some treatments are more effective for younger patients.

There are several kinds of external beam radiation therapy: the proton beam and the electron beam to name but two. Proton beam prostate cancer therapy goes back to 1954 so has a long and successful history.

Electron beam radiation therapy is much newer but is also successful. All external radiation therapy for prostate cancer treatment aims beams of particles at the cancerous cells in the prostate to kill them.

These external radiation beams can be closely controlled both in the depth of penetration and the width of the beam so that there is virtually no collateral damage of adjacent healthy tissue, which means that side effects are kept to a minimum.

The beams in external beam radiation therapy are created by a machine, an accelerator, outside the body, but there is another radiation treatment, whereby a device, a seed implant, is inserted into the body, which gives off a dose of radiation continuously.

This is invasive radiation therapy and is called seed radiation treatment or brachytherapy. Your doctor will decide which method to use depending on how far progressed the cancer you have is.

In the case of external beam radiation therapy, the doctor or surgeon will have to 'map' you and the tumor, which means that they will have to determine the best points for the beams to enter your body. As they work out these points they will put marks on your skin.

These marks will enable the doctors to go back over several (usually seven or eight) weeks and repeat the procedures exactly. The marks are made with indelible ink, but they will wear off over time.

In order for the external beam radiation to target the same part of the prostate gland every time the beams will not only have to enter the body at the right spot, but the body will have to lie in exactly the same position too. This often means lying immobilized in a body cast to stop you moving about.

There may be short and long term side effects, but they are usually confined to loss or pubic hair, itchiness, diarhoea and frequent urination. A patient may get some, none or all of these side effects.

The side effects of the disease of prostate cancer and radiation treatment usually wear off several weeks after the last session of external beam radiation therapy and many of them can be treated with medication especially water retention and itchiness.