Colorectal for FRCS (Gen Surg)

This is a large non-pedunculated colorectal polyp (20 mm or more) with every feature of a benign lesion: granular surface, no depression and a regular pit pattern. UK guidance is that such lesions are discussed by a complex polyp team and treated endoscopically as first-line, because mucosal resection in expert hands clears over 90% with far less morbidity and mortality than colectomy. Right hemicolectomy for a benign polyp is over-treatment unless endoscopic removal fails or is not feasible. Wedge resection is a second-line combined procedure. Observation leaves a lesion with a substantial risk of progression, and ablation alone gives no histology and incomplete treatment. Reference: Rutter MD et al., BSG/ACPGBI guidelines for the management of large non-pedunculated colorectal polyps, Gut 2015.

This is an early rectal cancer in which the choice between local excision and total mesorectal excision turns on the depth of invasion within the bowel wall. MRI is the standard local staging test because it shows the mesorectal fascia, nodes and extramural venous invasion, but it separates T1 from T2 poorly. Endorectal ultrasound resolves the layers of the rectal wall and is the better test when MRI suggests disease amenable to local excision. Diffusion-weighted MRI helps with response assessment, not wall layers. PET-CT and CT colonography add nothing to T staging, and repeat biopsies sample the surface without measuring depth. Reference: Glynne-Jones R et al., ESMO rectal cancer guidelines, Ann Oncol 2017; Colorectal Surgery: A Companion to Specialist Surgical Practice 7e.