T1 colorectal cancer management in the era of minimally invasive endoscopic resection

Table 5 Emerging treatment options for T1 colorectal cancer

Emerging technique	Description	Application in T1 CRC	Outcomes and evidence
Endoscopic submucosal dissection for suspected focal deep submucosal invasion	En-bloc endoscopic resection for lesions with optical evaluation suggesting focal deep submucosal invasion	For patients preferring or only eligible for conservative management, who would otherwise be referred to first-line surgery	Retrospective study of colorectal neoplasia with focal deep invasion found R0 resection of 77% and curative resection in 27%[62]
Endoscopic intermuscular dissection	Dissection between inner (circular) and outer (longitudinal) muscularis propria	For rectal cancers, particularly with a concern for deep submucosal invasion	Prospective cohort study of T1 rectal cancer demonstrated technical success of 96%, R0 resection of 81%, and curative resection of 45%[63]
Colonoscopy-assisted laparoscopic wedge resection	Laparoscopic resection and closure of colonic lesions under direct intraluminal endoscopic guidance	For colon cancers, particularly with deep submucosal invasion	Case series of patients with high grade dysplasia or T1 colon cancer demonstrated R0 resection of 89%[67]
Neoadjuvant and adjuvant chemoradiation1	Use of chemoradiation or chemotherapy alone before or after resection to increase efficacy of local excision1	For downstaging early rectal cancer or for prevention of recurrence following local excision of high risk T1 CRC	NEO trial (phase II) of early rectal cancer showed 57% downstaging, 79% organ preservation, and 90% 2-yr local regional relapse free survival[73]. Systematic review subgroup analysis of T1 CRC treated with adjuvant chemoradiation showed local recurrence rate of 3.9%[75]

¹Use prior to/followed by local excision with transanal endoscopic surgical techniques.

CRC: Colorectal cancer.