Cl Deijen, MD1, S Velthuis, MD2, Jb Tuynman, MD, PhD1, C Sietses, MD, PhD2, Wjhj Meijerink, MD, PhD1, Hj Bonjer, MD, PhD1. 1VU University Medical Center Amsterdam, 2Ziekenhuis Gelderse Vallei Ede
Introduction and rationale: Laparoscopic total mesorectal excision (TME) has gained popularity over the past decade as a minimally invasive alternative to open TME for the surgical treatment of rectal cancer. Recent studies showed improved short-term outcomes as well as comparable oncological outcomes between open and laparoscopic TME for rectal cancer. However, resection of mid and distal rectal carcinomas is associated with high rates of involved circumferential resection margins (CRMs) and high rates of permanent colostomies. In attempt to improve the quality of the TME procedure in low rectal cancer and further improve oncological results the transanal total mesorectal excision (TaTME) has been developed, in which the rectum is dissected transanally according to TME principles. The objective of this study is to assess the role of TaTME in the treatment of rectal cancer.
Study design: The study will be a superiority, international, randomized, multicenter trial comparing traditional laparoscopic and transanal TME for rectal cancer.
Study population: Patients with histologically proven single mid or distal rectum carcinoma (0 to 10 cm from anal verge) at MRI, eligible for surgery with a curative intent, are included. Patients with a T1 tumor suitable for local excision, T3 tumors with a suspected involved circumferential resection margin and T4 tumors are excluded.
Endpoints: The primary endpoint of the study is the involvement of CRM. Secondary endpoints include sphincter saving procedures, short-term morbidity and mortality, local recurrence, disease-free and overall survival at 3 and 5 years, completeness of mesorectum and quality of life.
Randomization and statistics: Randomization will be in a 2:1 ratio in favor of the TaTME procedure. It will be stratified for participating center, preoperatieve (chemo)radiotherapy, T-stage, height of the tumor (mid or low) and gender. In laparoscopic TME the percentage of involved CRM is estimated 10%. For showing a difference of 5% (10% versus 5%) with a two-sided level of significance of 5% and a power of 80% a total of 935 patients is needed, 623 patients in the TaTME arm and 312 patients in the laparoscopic TME arm. All analyses will be performed on intention-to-treat basis.
Conclusion: The hypothesis is that TaTME will result in a lower rate of involved CRM and therefore lower rate of local recurrence. Furthermore, because of direct endoscopic visualization, even in very low tumors a coloanal anastomosis can be created, resulting in a lower colostomy rate compared with laparoscopic and open resection. Because long-term outcomes are unknown, within a trial setting the technique can be standardized and quality control can be performed.