Author response to: Comments on: Norwegian moratorium on transanal total mesorectal excision

Editor We appreciate the invitation to respond to comments from Lacy et al. on our Leading Article reporting the moratorium on transanal total mesorectal excision (TaTME) for rectal cancer in Norway. We would like to point out a number1 of misunderstandings that may have occurred. The Leading Article is a ‘letter of warning’ after a number of serious and unexpected events related to the TaTME approach, and is not intended as any kind of general judgement of the procedure. We reported these events as observations that need to be corroborated in depth, and a Norwegian audit will be submitted in the near future. Lacy et al. comment on the median time of 11 months to local recurrence (LR) among those who developed LR, and state that this would not be possible as the number of events is less than 50 per cent. However, the reported median value includes all patients with LR, thus representing a subgroup with 100 per cent LR, which allows the median value to be applied as a measure of the central tendency of this variable. This is not to be confused with calculations on the entire patient population, of whom 9⋅5 per cent had a LR. The other main concern of Lacy et al. is their fear that our observations of inferior treatment effects may discredit the TaTME approach. However, we do not draw any conclusions on the TaTME approach per se; but we do point out, like others2–5, that there are concerns about this technique that need appropriate scrutiny to provide sufficient high-quality evidence. We have to acknowledge all observations regardless of whether or not they are in favour of the new procedure. This is of particular importance to safeguard our patients by strict routines when novel treatment approaches are tried6, and to prevent novel treatments from being discredited.