Radiotherapy

What to expect

If you are undergoing external radiotherapy, you will have imaging scans beforehand to pinpoint the exact location, size and shape of the tumour. If you’ve had surgery to remove the tumour, scans will be taken of the site it was removed from. External radiotherapy is given using a linear accelerator machine, which is similar to an X-ray machine. The machine doesn’t touch you and the treatment is painless, but you may experience some pain and discomfort afterwards. The number and frequency of sessions will depend on the size, location and type of tumour you have.

There are different types of internal or contact radiotherapy, which delivers high doses of radiation directly into, or very close to, the tumour. For example, the Papillon technique may be used for early stage rectal cancer. Your oncologist will advise on the best approach for your particular type of bowel cancer.

Stereotactic radiotherapy

Stereotactic radiotherapy (or stereotactic ablative radiotherapy – SABR) is an advanced technique that uses highly focused beams of radiation to destroy cancer cells. By directing radiotherapy beams at the tumour from many different angles, it can pinpoint the cancer cells with minimum damage to surrounding healthy tissues. Stereotactic radiotherapy is used to treat localised bowel cancers as well as secondary cancers that have spread to other tissues in the body. It can also be used to target areas where cancer has returned after previous radiotherapy. Treatment is given as an outpatient over three to five sessions. You won’t need anaesthetic and can go home the same day. The advantage of stereotactic radiotherapy over conventional approaches is that it minimises the amount of healthy tissue exposed to radiation which means the side-effects are fewer. And because the tumour receives a higher radiation dose than with conventional radiotherapy, outcomes can be better.

MRI-guided radiotherapy

The Bowel Cancer Clinic also specialises in MRI-guided radiotherapy which combines MRI imaging with radiotherapy to ensure that the tumour is targeted with pinpoint accuracy. As with stereotactic radiotherapy, by ensuring the radiotherapy is delivered to the tumour rather than the surrounding healthy tissue, the treatment is more effective and the risk of side-effects lower. By making sure the tumour receives the optimum amount of radiotherapy each time, it can also be possible to reduce the number of radiotherapy sessions required.

Side-effects

In the short term, radiotherapy can cause a range of side-effects, including tiredness, sore skin, bowel and bladder problems and difficulty sleeping. Longer-term side effects may include changes in bowel habits, infertility, impact on sexual function, bladder irritation and damage to your pelvis which can lead to fractures. Your oncologist will discuss any possible side-effects with you and how to manage them.