The study will be a non-inferiority, international, randomized, multicenter trial comparing traditional laparoscopic and transanal TME for rectal cancer.
Patients with histologically proven single mid or distal rectum carcinoma (0 to 10 cm from anal verge) at MRI, eligible for restorative 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.
The primary endpoint of the study is the local recurrence rate at 3-years follow-up. Secondary endpoints include sphincter saving procedures, short-term morbidity and mortality, involved circumferential resection margin (CRM), disease-free and overall survival at 3 and 5 years, completeness of mesorectum and quality of life. Randomization will be in a 2:1 ratio in favor of the TaTME procedure. It will be stratified for participating center, preoperative (chemo)radiotherapy, T-stage, height of the tumor (mid or low) and gender. In laparoscopic TME the percentage of local recurrence at 3-years follow-up is estimated 5%. With the non-inferiority margin set at 4%, with a one-sided level of significance of 2.5% and a power of 80%, a total of 1104 patients is needed, 669 patients in the TaTME arm and 335 patients in the laparoscopic TME arm. All analyses will be performed on intention-to-treat basis.
The hypothesis is that TaTME will result in a comparable local recurrence rate at 3-years follow-up with benefit of lower morbidity and conversions. 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.