Over the last twenty years a number of clinical trials have looked at the use of radiotherapy with surgery in the treatment of rectal cancers.

These studies have shown that giving radiotherapy to people who are having an operation to remove a cancer of the rectum reduces the risk of the growth coming back in the pelvis. In the past this has been a relatively common problem, which was difficult to treat successfully. Although radiotherapy helps reduce the chances of this particular problem developing, it is still not certain whether it actually increases the overall cure rate for rectal cancer. Also, in recent years the surgery of rectal cancer has improved, so fewer people now get local recurrence, and so there may be less need for radiotherapy.

Another uncertainty is whether it is best to give the radiotherapy treatment before or after the surgery. Because improved surgery has led to less people needing radiotherapy, the suggestion is that it might be best to do the operation and then offer radiotherapy only to those people  who might be at more risk of the cancer coming back after surgery.

Evidence so far from a large Dutch study suggests that radiotherapy given before surgery significantly reduces the risk of a local recurrence in rectal tumours that are situated near the anus. However, pre-op radiotherapy was not shown to have any significant effect on tumours situated higher up the rectum. You need to bear in mind that the data from this study is still immature, as the people in the study have only been followed up for a couple of years.  Research is still needed to clarify the role of radiotherapy in the treatment of rectal cancers.

To try and answer these questions, the Medical Research Council has organised a clinical trial in the UK for people who are going to have an operation to remove a rectal cancer. People who take part in the trial will either have a five day course of radiotherapy before their operation or have their operation and then (only if it is thought there might be a risk of the cancer coming back) receive a course of radiotherapy and some chemotherapy. Because it is important that the question is answered scientifically, with no bias, the choice of which approach is used is made randomly by a computer. This means that neither the patient nor their doctors can influence the decision as to which treatment is given.

The Medical Research Council trial has been fully scientifically and ethically approved so you can feel quite confident about taking part. Also the Medical Research Council has produced information for patients about the trial and your doctors should let you have a copy of this to help you decide what to do.

Remember that the choice is yours and nobody will force you to go into a trial or try and persuade you against your will. Do discuss this with your doctors so that you can make a fully informed choice.

Even if you decide not to go into the study it should still be possible to have radiotherapy treatment before your operation if that is what your doctors think is the best course of action..