Assessing clear vertical margin following endoscopic resection of T1 rectal cancers: a multicentre comparison of current guidelines

Aims International guidance varies in the definition of a clear vertical margin and recommendation for additional surgery following endoscopic resection (ER) of T1 colorectal cancer. The recommendation for surgery for rectal lesions in particular has significant bearing due to the high morbidity of surgery and potential impairment on quality of life. We aimed to assess the differences in residual tumour and recurrence between patients with<0.1mm, 0.1-1mm, or>1mm clear vertical margin (VM) following ER of T1 rectal cancers.

Methods We performed a multicentre retrospective review of histopathology reports for patients following ER for T1 rectal cancers at three UK centres (1 tertiary and 2 general hospitals). Histology reports of patients undergoing additional surgery were assessed, as well as endoscopy reports of patients undergoing surveillance without additional surgery.

Results 344 patients with T1 rectal cancer were identified. 156 patients were excluded due to primary surgery, or a diagnosis of IBD or polyposis. Of 188 remaining ERs, median age was 68 years with 119 (63%) males. Median lesion size was 24mm (8-120mm). 79% were resected with endoscopic mucosal resection (EMR), and 21% with endoscopic submucosal dissection (ESD). 54% were resected en bloc.  68 (36%) patients had VM<0.1mm or that was not assessable, 51 (27%) had VM 0.1-1mm, and 36 (19%) had VM>1mm. VM was not available for 33 patients. Of the patients with VM<0.1mm or not assessable, 4/29 had residual tumour in the surgical specimen, and 5/39 had local recurrence on endoscopic follow-up without additional surgery. Of patients with VM 0.1-1mm, 0/10 undergoing additional surgery had residual tumour in the surgical specimen, and 5/41 had local recurrence on endoscopic follow-up without additional surgery. Of patients with VM>1mm, 0/5 undergoing additional surgery had residual tumour in the surgical specimen, and 3/31 had local recurrence on endoscopic follow-up without additional surgery. Of patients where a measurement of VM was not available, 1 had local recurrence on endoscopic surveillance.

Conclusions Our data suggests a clear vertical margin>0.1mm is not associated with residual tumour in the surgical specimen, and does not increase the risk of local recurrence on surveillance for those undergoing ER alone. This may spare a recommendation for additional surgery for a significant proportion of patients undergoing ER of T1 rectal cancer.

Publication History

Article published online:
27 March 2025