Transanal total mesorectal excision for stage II or III rectal cancer: pattern of local recurrence in a tertiary referral center

Background For mid and low rectal cancer, transanal total mesorectal excision (TaTME) has been established as an alternative approach to laparoscopic surgery. However, there are concerns about an unexpected pattern of local recurrence. This study aimed to analyze the pattern of local recurrence for patients treated with TaTME in a tertiary referral center. Methods A retrospective single-center analysis was performed. Since 2011, all patients with rectal cancer undergoing TaTME with curative intent were prospectively included in a standardized database. Patients with tumors within 12 cm, clinical stage II or III were included. The primary endpoint of the study was the overall local recurrence rate, together with a critical analysis of the patterns of local failures. Results Two hundred and five patients were included in this analysis. At the time of surgery, patients had a mean age of 67.1 years (SD 12.3), and 66.8% were male. Neoadjuvant therapy was administered in 73.7%. Mesorectal specimen quality was complete or near-complete in 98.5%, while circumferential resection margin was ≤ 1 mm (including T4 tumors) in 11.8%. After a median follow-up of 34.3 months (95% CI 30.1–38.5), 3.4% ( n = 7) presented with local recurrent disease. Six out of the seven patients were also diagnosed with hematogenous metastases. Of the seven patients, three presented with at least one of the following risk factors: T4 tumor, N2 disease, incomplete mesorectal specimen, or positive CRM. Local failure was noted posteriorly ( n = 3), laterally ( n = 2), anteriorly ( n = 1), and in the axial compartment ( n = 1). Median time to relapse was 31.5 months (10.3—40.9). The median follow-up after local recurrence was 7.9 (95% CI 6.7–9.1) months, with an overall survival of 85.7%. Conclusions TaTME provided satisfactory local recurrence outcomes, and the most common patterns of failure were in the central pelvis.