Surveillance Digital Rectoscopy After Local Excision of Rectal Tumours

BACKGROUND Transanal excision of rectal tumours describes the excision of both benign and malignant rectal lesions avoiding the need for major rectal resection. Traditional transanal approaches facilitated the excision of lower third rectal tumours using a trans-anal retractor. Since its introduction in the 1980s, transanal endoscopic microsurgery (TEMS) has established itself as an oncologically effective and safe approach to transanal excision of neoplasms throughout the rectum. More recent developments using laparoscopic (TAMIS) and now robotic platforms (R-TAMIS) provide alternative approaches. Local excision techniques are associated with reduced comorbidity when compared with radical rectal resection (i.e. Total Mesorectal Excision, TME) e.g. death, bleeding, genito-urinary dysfunction and anastomotic leak and need for a stoma. The development and evolution of neo-adjuvant therapy for rectal cancer with significant rates of complete response, demonstrates the potential for organ preservation and may be used alongside local excision techniques, as studied in the TREK, STAR-TREK and GRECCAR-2.

However, it is suggested that when performed for cancer, oncological outcomes may be poorer in patients undergoing local excision compared to radical resection. Current evidence regarding recurrence and survival rates is inconsistent, with some studies suggesting equivalent outcomes, but other studies reporting worse oncological outcomes. As such, regular, high quality post-operative surveillance of the rectum in patients under local excision is critical. Current methods of surveillance for the detection of recurrence commonly include multimodal radiological cross-sectional imaging (magnetic resonance imaging (MRI) and computerised tomography (CT)) and endoscopic (flexible sigmoidoscopy/colonoscopy) surveillance. There are currently no established UK guidelines for surveillance of this patient cohort, yet it is clear that even where local excision of a benign lesion is performed, endoscopic surveillance remains critical in identifying and managing recurrence or metachronous rectal pathology.

1.2 RATIONALE FOR STUDY

COVID-19 had a seismic impact on the provision of care across medicine, not least on the delivery of timely endoscopic examinations, resulting in a significant reduction in activity and exponential increase in waiting times which persists to date. Surveillance procedures are perhaps most at risk of delays, especially when triaged against patients with positive faecal immunohistochemistry tests (FIT) with a high chance of significant pathology. Local data indicates poor compliance with surveillance schedules (Table 1) particularly for endoscopic procedures. In total 20.8% of flexible sigmoidoscopy requests for surveillance after TEMS rectal cancer excision were performed 6 or more months after the scheduled time.

Year 1 2 3 Months 4 8 12 18 24 30 36 Total Number of Patients 36 34 34 33 32 32 32 Pelvic MRI 20 (56%) 15 (44%) 11 (32%) 10 (30%) 6 (19%) 5 (16%) 1 (3%) CT (CAP) 14 (41%) 8 (25%) 3 (9%) Flexible Sigmoidoscopy 15 (42%) 6 (18%) 8 (24%) 7 (21%) 2 (6%) 2 (6%) 2 (6%) Table 1 - Number (%) of Patients Receiving Surveillance <1 month from scheduled date