At this year’s ESCP meeting in Milan, Italy, Dr Albert Wolthuis from the University Hospital of Leuven, Belgium, examined the limitations of total mesorectal excision (TME) and assessed a different approach - transanal total mesorectal excision (TaTME). Although still in its infancy, Dr Wolthuis discussed the advantages and drawbacks of this approach and why he believes TaTME will be the procedure of choice for low rectal cancer in the future…
Dr Wolthuis began by explaining that although the exact prevalence of low rectal cancer is unknown, according to the Surveillance, Epidemiology, and End Results (SEER) database, approximately 41 new cases of colorectal cancer per 100,000 men and women are diagnosed each year. Approximately 20% of cases of colorectal cancer are associated with familial clustering such as Lynch syndrome or familial adenomatous polyposis (FAP). Other risk factors associated with the development of colorectal cancer are inflammatory bowel disease, smoking, red and processed meat consumption, alcohol consumption, diabetes, low-levels of physical activity, metabolic syndrome and high body mass index.
He said that the treatment of distal rectal cancer is complex and depends on adequate clinical and radiological staging. There are different therapeutic modalities including chemotherapy, radiotherapy and surgery or a combination of these treatments.,= Based on different treatment protocols, rectal cancer treatment may be different between countries, but the cornerstone of (locally advanced) distal rectal cancer is TME surgery. Nevertheless, Dr Wolthuis stressed that when it comes to surgical treatment, the surgeon should take patient choice, previous treatment, oncological and functional outcome into account when discussing surgical options with the patient.
“Nowadays, the main debate is how to perform TME,” he explained. “There are different surgical options for sphincter saving surgery including open, laparoscopic or robotic TME. Recently, three major clinical trials comparing open and laparoscopic TME were published. The American and Australian TME-trials did not show non-inferiority regarding the laparoscopic approach. The COLOR 2 trial, however, showed that laparoscopic TME has similar locoregional recurrence rates and disease-free and overall survival, compared to open surgery.”
He said a TME remains a difficult procedure for several reasons, particularly because of poor visualisation and suboptimal dissection (causing traction and potential tearing of the specimen) with non-adapted instruments deep down in the pelvis (especially narrow obese male pelvis) making the most distal (recurvating) part of a TME sometimes very difficult.
As a result, it is sometimes difficult to get negative circumferential resection and distal resection margins with an incomplete TME specimen and conversion to open surgery might be necessary. Furthermore, due to a confined space and limitation of angulation of actually-available endoscopic staplers, transection of the rectum just above and perpendicular to the pelvic floor can be cumbersome. It has been shown that the use of more than two firings was associated with an increased risk for anastomotic leakage of the double stapled colo-anal anastomosis.
To compensate for abovementioned problems with distal TME-surgery, the approach of the distal part of the TME has changed with the introduction of the transanal approach. With this approach the surgeon is in charge and has direct control of the distal resection margin and he/she can choose the exact location of the future anastomosis. Advantages of a TaTME are clear: a transanal approach provides an ergonomic platform to facilitate dissection under direct visual control. Optimal distal resection margin and future anastomosis can be chosen by placing a purse string. A hybrid approach (laparoscopic-transanal) allows for two operating teams performing TME, which could reduce operating time. Moreover, conversion may no longer be an issue.
Apart from these (presumed) benefits, surgeons should adapt to new surgical anatomy and anatomical landmarks. A retrograde dissection has already resulted in a perioperative complication unique to TaTME, which is damage to the bulbar urethra. A word of caution should warn unexperienced or poorly-trained surgeons who are willing to embark on TaTME, he warned.
“The concept of a TaTME has been developed in animal and cadaver studies and is now getting widespread international attention to implement this into daily clinical practice,” he explained. “Some small feasibility studies showed that TaTME is feasible and safe and the LOREC registry was initiated to collect evidence and to develop new hypotheses for the research in TaTME-surgery. Moreover, two new initiatives (GRECCAR, COLOR 3) were started to compare TaTME with laparoscopic TME. Although this procedure is still in its infancy and the need for a well-experienced laparoscopic and transanal surgical team is required, I think that TaTME will be the procedure of choice for the surgical treatment of low rectal cancer in the future.”
