Transanal total mesorectal excision for rectal cancer Assessment of oncological safety

The aim of this thesis was to obtain a better insight into the oncological safety of Transanal total mesorectal excision (TaTME) for rectal cancer patients. TaTME was introduced in 2010 as a new surgical technique to overcome the limitations experienced during conventional rectal resection. When implementing a new surgical technique, it is essential to carefully evaluate its outcomes and assess potential harms and benefits. The evolution and development of TaTME was described in the introduction, concluding that the quick worldwide adoption of the technique did not concur with IDEAL principles. In Part 1, we focused on short-term outcomes of TaTME and learnt that important histopathological characteristics, actually surrogate factors for oncological outcome, were within acceptable ranges and were comparable to conventional lapTME. Thus suggesting short-term safety of this relatively new technique. On national levels in the Netherlands and the United Kingdom, histopathological outcomes suggested safety, although implementation of the technique was unregulated and unmonitored. In Part 2, the recently strong debated cancer recurrence rates after TaTME were examined, and found reassuring local recurrence rates, suggesting medium-term oncological safety of TaTME. Although a final answer on the efficacy and safety of TaTME can only be given by a randomised controlled trial, from this thesis, we may conclude that TaTME seems an oncological safe option to treat patients with rectal cancer.