Conformal radiotherapy

Conformal radiotherapy uses the same radiotherapy machine, a linear accelerator, as the normal radiotherapy treatment but metal blocks are placed in the path of the x-ray beam to alter its shape to match that of the cancer. This ensures that a higher radiation dose is given to the tumour. Healthy surrounding cells and nearby structures receive a lower dose of radiation, hence the possibility of side effects being reduced.

Precise positioning of the radiotherapy machine is very important for conformal radiotherapy treatment and a special scanning machine may be used to check the position of the internal organs at the beginning of each treatment.

Intensity modulated radiotherapy (IMRT)

High-resolution intensity modulated radiotherapy also uses a multi-leaf collimator, with the layers of the collimator moved while the treatment is being given. This method is likely to achieve even more precise shaping of the treatment beams and allows the dose of radiotherapy to be constant over the whole treatment area.

Although research studies have shown that conformal radiotherapy and intensity modulated radiotherapy may reduce the side effects of radiotherapy treatment, it is possible that shaping the treatment area so precisely could stop microscopic cancer cells just outside the treatment area being destroyed. This means that the risk of the cancer coming back in the future may be higher with these specialised radiotherapy techniques. Research studies currently being carried out should reveal whether this is the case.

Stereotactic radiotherapy

Used to treat brain tumours, this technique directs the radiotherapy from many different angles so that the dose going to the tumour is very high and the dose affecting surrounding healthy tissue is very low. Before treatment, several scans are analysed by computers to ensure that the radiotherapy is precisely targeted, and the patient's head is held still in a specially made frame while receiving radiotherapy, with several doses given. The treatment is available only in specialist hospitals and is not suitable for all patients.

The Gamma Knife

This type of radiotherapy, again for brain tumours, uses very precisely targeted beams of gamma radiotherapy from hundreds of different angles. Only one session of radiotherapy, taking about four to five hours, is needed.

For this treatment a specially made metal frame is attached to the head. Several scans and x-rays are then carried out to find the precise area where the treatment is needed. During the radiotherapy, the patient lies with their head in a large helmet, which has hundreds of holes in it to allow the radiotherapy beams through. Again, as with stereotactic radiotherapy, the treatment is available only in specialist hospitals and is not suitable for all patients.

Internal radiotherapy (Brachytherapy/implant therapy/seed implantation)

Available in some hospitals in the UK, internal radiotherapy can be carried out under a general anaesthetic or sometimes using spinal anaesthetic (epidural). Small radioactive metal "seeds" are inserted into the tumour so that radiation is released slowly over a period of time. Although the seeds are not removed the radiation gradually fades away over the course of a year.

Around 80-100 radioactive seeds are inserted through the skin between the prostate and the anus and guided into the prostate gland. As the procedure may cause some swelling of the prostate, which can sometimes lead to blockage of the urethra, a catheter is temporarily inserted into the bladder to drain the urine. This may be removed after a couple of hours or left in place overnight.

Antibiotics are given after the implant, to prevent infection. Most men go home the day after the implant, but some leave hospital as soon as they have recovered from the anaesthetic and are able to pass urine normally. After the implant it is best to avoid heavy lifting or strenuous physical activity for two or three days.

All the radioactivity is absorbed within the prostate but women who are (or could be) pregnant, and children are not recommended to "stay very close" to the patient for long periods of time.

The seeds remain permanently embedded in the prostate gland, but there is a tiny chance of a single seed being passed in the semen during sexual activity. So patients are advised to use a condom for the first few weeks after implant.

Common side effects of brachytherapy include mild soreness, temporary bruising and discoloration between the legs, and blood in the urine.

However Brachytherapy may be less likely to affect the bowel than external beam radiotherapy, although the risk of urinary problems is higher. Up to one in seven men may not be able to pass urine immediately after the procedure and may need to have a catheter inserted for a time.

As with external radiotherapy, impotence develops in up to 50 per cent of men some years after the treatment.

Some men find that they have pain or discomfort on passing water, need to pass urine more often or have a weaker urine stream (usually improves over 6-12 months as the seeds lose some of their radioactivity). Drinking plenty of fluids and avoiding caffeine may help to reduce these effects.