The standard treatment for locally advanced rectal cancer or low rectal cancer (within 6cm of the anus) is chemo-radiotherapy (CRT) followed by surgery, either anterior resection or abdominal peritoneal resection respectively. The latter means that patients undergoing this procedure will require a life-long stoma, often impairing quality of life.
10-25% of patients who undergo CRT have a pathological complete response (pCR), meaning that no evidence of the tumour can be detected. Surgery presently remains standard of care for these patients, but there is significant morbidity and mortality associated with rectal surgery, particularly in elderly patients and those with significant co-morbidities. Results from the United Kingdom National Bowel Cancer project shows that the 30-day mortality rate after rectal surgery is significantly higher for patients over the age of 75 years compared with younger patients.
Traditionally, rectal surgery takes place 6 weeks after CRT, but the maximum amount that a tumour can be down-staged (lowering the stage of cancer based on shrinkage) may require a longer period of time depending on individual tumour response. Some patients with tumours that show a good but continuing response at the end of CRT may have better surgical outcomes if they defer surgery. The optimal time to maximal response is currently unknown, so the optimal imaging timetable for such patients at present is unclear.
This study is designed to establish the time to maximum tumour response following CRT, and to investigate whether surgery can be safely avoided within the tight framework of the trial follow-up schedule in a small group of patients where the cancer becomes undetectable by imaging modalities.
The study uses MRI in combination with other types of scans (PET CT) and clinical examination to assess for a continued response to CRT. It is important to note that surgery is NOT withheld from patients entering this study. Indeed, surgery is an option at each stage of patient follow-upbased on:
- There being no further incremental imaging response and complete response not achieved
- Evidence of tumour regrowth (clinical imaging, endoscopy or tumour marker)
- Patient Choice
- If a status of `no detectable disease` by serial MRI, CT-PET and clinical assessment is achieved and the patient wishes not to have surgery, they will continue to be carefully monitored within the framework of the trial follow-up protocol.
The Primary Investigator was, Dr Diana Tait.