[Prerequisites for Safe Implementation of Transanal Total Mesorectal Excision].

Transanal total mesorectal excision (TaTME) is an innovative and technically demanding surgical approach for the treatment of rectal cancer. This review summarises the international consensus statements on prerequisites and training requirements for safe implementation of this complex procedure. Recommendations will be discussed on the basis of the published surveys from dedicated training centres. Furthermore, experience is shared on mentored TaTME cadaveric courses (video) and an initial clinical series of 102 TaTMEs. The procedure should be performed primarily by postgraduate colorectal surgeons. Initially, a structured training program at designated training centers is mandatory. Cadaver training and proctoring are the central elements required to ensure safe implementation of TaTME in clinical practice. However, validation of TaTME training concepts needs further work. Evaluation of the first pioneering series indicates a learning phase with at least 40 operations. Above the cut-off, lower complication rates and acceptable quality of specimen are achieved. In our series, morbidity decreased significantly (Clavien-Dindo ≥ III: 29 vs. 9%). With the indication for TaTME, we find a median of 6 risk factors (4 - 8) for an unfavourable outcome after abdominal TME alone. Only high volume centres with a concentration of appropriately selected patients could aim for a proposed TaTME frequency of 20 per year. Structured training programs for TaTME are justified and must be completed before implementation in clinical practice. The case volume effect for the learning curve and individual patient selection are crucial and support the concentration of the new method in high volume centres.