Transanal total mesorectal excision (TaTME) is an innovative, minimally invasive technique derived from the concept of natural orifice transluminal endoscopic surgery. Since its introduction in 2010, TaTME has been primarily used for mid- and low-rectal cancers, particularly in patients with anatomically challenging pelvises. Evidence from international registries, single-center cohorts, and systematic reviews indicates that, when performed in high-volume centers by surgeons who have completed structured training, TaTME can achieve high rates of circumferential resection margin negativity and satisfactory TME specimen quality. In well-selected and appropriately matched patients, intermediate oncological outcomes, including local recurrence and survival, were comparable to those of conventional laparoscopic TME. However, TaTME remains associated with ongoing concerns, including a steep learning curve, a relatively high incidence of low anterior resection syndrome, and persistent debate regarding oncological safety, particularly following reports of atypical local recurrence patterns from national registries. Focusing on oncological safety, this review provides a critical evaluation of evidence across three interrelated domains: pathological quality, long-term oncological outcomes, and postoperative functional outcomes and quality of life. Importantly, available data suggest that early oncological concerns may have been partly attributable to premature adoption, inadequate training structures, and insufficient quality assurance during the initial implementation phase, rather than to inherent oncological limitations of TaTME. Accordingly, TaTME should be implemented only within a rigorously regulated framework incorporating structured training, multidisciplinary decision-making, and continuous quality monitoring, while carefully balancing oncological radicality with functional preservation and long-term quality of life.