Can we save the rectum by watchful waiting or transanal surgery following (chemo)radiotherapy versus total mesorectal excision for early rectal cancer?

This trial is for adults in the UK (aged 16 and over) who have recently been diagnosed with early-stage adenocarcinoma of the rectum. The tumour must be confirmed by a biopsy and must not have spread deeply into surrounding tissues or to other parts of the body, as checked by an MRI scan or ultrasound.

To take part, your hospital cancer team (multidisciplinary team) must agree that all the trial treatments are safe and suitable options for you. You also need to be reasonably active and well enough to carry out daily tasks, and able to attend regular hospital appointments.

You cannot join if the cancer has spread further, or if you have had certain other cancers recently. Because radiotherapy can harm an unborn baby, women who could become pregnant will need a negative pregnancy test, and both men and women taking part must agree to use reliable contraception during and shortly after treatment.

If you join the study, you will be placed into a treatment group. Depending on your group, you may have standard surgery to remove the rectum, a short course of radiotherapy, or a longer course of radiotherapy combined with chemotherapy tablets. Radiotherapy is given as outpatient visits at the hospital. If you receive radiotherapy, you will have detailed checks a few weeks later, including MRI scans, camera tests (endoscopy), and physical exams to see how well the tumour has responded.

If the tumour has cleared completely, you will be monitored very closely with regular scans and check-ups rather than having surgery. If a small amount remains, you may have a minor operation through your bottom to remove it. If the cancer does not shrink enough, you can still have standard surgery. Follow-up continues for several years to make sure the cancer has not returned and to monitor your bowel health, with check-up visits every few months at first.