About the study

Rationale
Colorectal cancer (CRC) is the second most prevalent cancer in the Netherlands, with 15,000 new cases per year and 5000 colorectal cancer related deaths. The Dutch National Colorectal Cancer screening program began in 2014 and is expected to save 1400 lives per year in the short term through early diagnosis and treatment of cancer. In the last few years two new highly promising innovative approaches have become available for minimally invasive en bloc resection of large nonpedunculated rectal lesions. One is a new surgical technique called transanal minimally invasive surgery (TAMIS) and the other is a new endoscopic technique called endoscopic submucosal dissection (ESD). Although both techniques are standard of care in the Netherlands, a direct randomised comparison between TAMIS and ESD is lacking. Therefore, the choice for either of both therapies remains operator-dependent instead of evidence-based.

Study Objectives
De Triassic study is to compare TAMIS with ESD with regard to:  

Primary Objective
Cumulative recurrence rate at follow-up rectoscopy after 6 and 12 months, either as visible residual disease confirmed at histology as neoplastic after removal or, if no visible residual disease is present, from biopsies of the scar.

Secundary objectives
• En bloc resection rate, defined as macroscopic removal of the lesion in a single piece.
• Radical (R0-) resection rate at histology for benign lesions
• Radical (R0-) resection rate  at histology for invasive lesions.
• Perceived burden and quality of life among patients
• Cost effectiveness at 12 months
• The need for additional trans abdominal surgery
• Complication rate
• To compare the long-term recurrence rate at follow-up rectoscopy at 12 months either as visible and subsequently resected recurrent/residual disease or, if not present, from biopsies of the scar.

Inclusion criteria

• Non-pedunculated polyp >2cm in the rectum where the bulk of the lesion is below 15cm from the anal verge found at colonoscopy
• ≥18 years old
• Written informed consent

Exclusion criteria
• Features of advanced disease or deep-submucosal invasion at optical endoscopic evaluation.*
• Features of advanced disease on cross-sectional imaging.*
• Prior endoscopic resection attempt
• The risk exceeds the benefit of endoscopic treatment, such as patients with an extremely poor general condition or a very short life expectancy
* Where there is discordance in the results, the optical endoscopic evaluation will be given the most weight and the case discussed by an expert panel of four study participants

Follow-up
Endoscopic
All patients must be receive follow-up by rectoscopy at 6 and 12 months after initial procedure
If recurrence is found at the 12-month colonoscopy this will be resected and further surveillance colonoscopie planned 6 months later (18 months after initial procedure)
• If there is no visible residual disease, please take 3 biopsies from the scar
• Note that there are forms to fill in after the follow-up rectoscopy in Castor

Questionnaires
Questionnaires will be directly sent from the LUMC to patients at baseline, after 4 days and 4 weeks after ESD/TAMIS and after the follow-up rectoscopy at 6 and 12 months.

Important notes
• Only endoscopists that have performed >25 ESD procedures are allowed to participate
• Only surgeons that have performed >25 TAMIS procedures are allowed to participate
• If there is no visible residual disease at follow-up, please take 3 biopsies from the scar
• The resected specimen needs to be correctly pinned out