How many people suffer from bowel problems following surgery for colorectal cancer, and what treatments are the best for managing these problems?

INTERVENTION: POLARiS is a phase III randomised superiority trial within a cohort (TWiC), with qualitative sub‐study and economic evaluation. The aim of the research is to explore the natural history of low anterior resection syndrome (LARS) over time and to compare sacral neuromodulation (SNM) and transanal irrigation (TAI) against optimised conservative management (OCM) for the treatment of major LARS. There are two primary comparisons for the RCT ‐ i) SNM versus OCM and ii) TAI versus OCM. The outcome of interest is the LARS score. Each comparison requires 350 patients. It is estimated that 600 patients in total will be needed to be recruited to the RCT in order to hit these sample size targets. Patients who have undergone a high or low anterior resection for rectal or sigmoid cancer within the last 10 years will be identified through cancer databases, note screening, outpatient clinics and in‐patients workload at NHS hospital sites. Registration and randomisations will be performed centrally using the CTRU automated 24‐hour registration/randomisation system, accessed by sites via the CTRU website. Participants who are eligible for and consent to the RCT will be randomised between two or three treatment options dependent on patient eligibility and availability of treatments at their hospital. Participants undergoing TAI will attend a one‐hour practical education session with a specialist nurse where the device and volume will be decided. Participants randomised to SNM will have a consultation with their local clinician performing the SNM procedure. Participants in the OCM group will have a consultation with a clinical member of the study where appropriate treatments will be instigated. Participants will be followed up for 24 months and will be reviewed at 3, 6, 9, 12 and 24 mo CONDITION: Low anterior resection syndrome ; Digestive System PRIMARY OUTCOME: LARS score measured using the LARS score questionnaire at baseline and every 3 months until 24 months post registration/randomisation INCLUSION CRITERIA: General inclusion criteria (cohort): 1. Diagnosis of rectal or sigmoid cancer 2. Low or high anterior resection (colorectal resection with anastomosis to the rectum) 3. Functioning anastomosis 4. Primary surgery less than 10 years before recruitment 5. At least 6 months since reversal of stoma or primary surgery if no stoma created 6. Aged = 18 years old 7. Able to provide written informed consent RCT inclusion criteria ‐ as above plus: 8. Major LARS symptoms within the last 3 months (Defined as a LARS score of =30) 9. Clinically appropriate for randomisation as determined by the treating clinician SECONDARY OUTCOME: RCT and cohort study:; 1. Health‐related quality of life and physical, psychological and emotional functioning, is measured using the EORTC QLQ C30, EORTC CR29 and the LARS iCAT questionnaire at baseline and at 3, 6, 12 and 24 months after registration/randomisation; 2. Incidence of adverse events related to the trial/trial procedures within 24 months of registration/randomisation, categorised using the CTCAE Grading (plus Clavien‐Dindo or ClassIntra classification for adverse events relating to surgery) using medical notes; ; Secondary outcome measures (RCT only); 1. Generic quality of life measured using EQ‐5D‐5L, at baseline 3, 6, 12 and 24 months after randomisation; 2. Treatment compliance will be measured using medical records ; 3. Cost‐effectiveness will be measured using a health resource use questionnaire at baseline, 3, 6, 12 and 24 months after randomisation and medical records