Norwegian moratorium on transanal total mesorectal excision

Abstract

The survival of patients with rectal cancer has improved over the past 30 years1. Standardization of total mesorectal excision (TME) with or without neoadjuvant treatment has decreased local recurrence risks. Transanal TME (TaTME) was introduced to improve access to the pelvis in difficult to reach scenarios (such as obese men), with the promise of better margins and specimen quality2. From January 2015 to December 2017, some 110 TaTME procedures were performed in Norway. Surgery for primary rectal cancer is undertaken in approximately 20 hospitals, four of which mainly did TaTME, but treatment of locally recurrent disease is centralized to one hospital in each of four health regions. In April 2018, the Norwegian Radium Hospital in Oslo reported a new, unexpected pattern of recurrences that occurred early after TaTME, giving rise to significant concerns. An immediate snapshot analysis was presented to the treatment centres at a national meeting. At least ten local recurrences (9⋅5 per cent) have been diagnosed, but the complete data are not currently available and the follow-up period is limited. The time to recurrence was short, a median of 11 months after surgery. Only a few cases involved technical problems that were described in the operation reports (for example entering an incorrect dissection plane). The recurrence pattern after TaTME was characterized by rapid, multifocal growth in the pelvic cavity and sidewalls, different from that typically observed after conventional surgery. Indeed, over the same interval, by comparison, the Norwegian Colorectal Cancer Registry3 found only 3⋅4 per cent local recurrence following TME. A national audit is under way to confirm these observations and to elucidate reasons for this unexpected, serious issue; these are unclear but may involve educational, technical and oncological issues. Yet the surgeons at the four large-volume hospitals, who are experienced in laparoscopic and transanal endoscopic surgery, were trained in TaTME at international workshops in England and Spain. One centre had international proctoring during the introduction of TaTME and two other centres reported to the TaTME registry in the UK4. To date, studies on TaTME have focused mainly on surrogate oncological endpoints observed at the time of surgery, such as specimen quality, circumferential resection margin involvement and the free distal margin4. End-stage oncological parameters, including overall survival, disease-free survival and local recurrence, have yet to be clarified5. Recurrence rates after TaTME were estimated at 4 per cent in one systematic review, and 2⋅8–8⋅9 per cent (high volume versus low volume centres)6, and 0–5⋅9 per cent in another7. The possibility of local recurrences related to the rectal transection and air flow during dissection from the perineum cannot be evaluated by examining the specimen; they can be assessed only by scrutinizing technical issues, such as the tightness of the purse-string suture. Neoadjuvant chemoradiotherapy might protect patients from tumour regrowth. In Norway, guidelines are based on the disease stage and the predicted circumferential resection margin. Decisions regarding neoadjuvant therapy are made independently of the planned procedure or approach, and currently about 30 per cent of patients receive it3. Neoadjuvant therapy was given to a much higher proportion (58 per cent) of patients in the TaTME registry4. Adjuvant chemotherapy is not administered routinely to patients with stage I–III rectal cancer in Norway. Are these issues factors contributing to the unusually high recurrence rate observed following TaTME in Norway? It seems unlikely as many countries have similar guidelines and the pattern of recurrence is unusual. This report highlights some fundamental challenges to introducing and implementing new surgical techniques. The introduction of new pharmaceutical drugs is strictly regulated, and involves testing in phase I studies (safety and dose ranging), phase II studies (efficacy) and phase III RCTs to document effectiveness. In contrast, no such regulations apply to surgical techniques. Randomized trials in surgery depend on the willingness of the surgical community to subject new treatment options to rigorous scientific evaluation in the absence of legal regulations. The history of surgery is rich with examples of new procedures that incur unexpected