Transanal total mesorectal excision (taTME) for rectal cancer: beyond the learning curve.

BACKGROUND

Transanal total mesorectal excision (taTME) is a surgical approach for low rectal cancer with a learning curve estimated at 40-50 cases. The experience among taTME surgeons beyond their learning curve is limited.

METHODS

A retrospective analysis of all taTME cases performed for rectal cancer at two tertiary care hospitals from 2014 to 2019 was conducted. Transanal surgeons had previously performed > 50 taTME cases. Demographic, perioperative, and short-term outcomes were analyzed.

RESULTS

Among 54 taTME patients, 74.1% were male and 27.8% had a BMI ≥ 30. Tumors were stage I (8), II (13), III (29), and IV (4). Complex cases included 4 local recurrences, 4 prior liver resections, and 2 with prior prostate cancer. Thirty tumors were located ≤ 6 cm from the anal verge. On staging MRI, 12 had a positive predicted circumferential radial margin (+CRM), and 4 had internal anal sphincter involvement (+IAS). Forty-seven patients received neoadjuvant therapy. A 2-team approach was used in 51 patients with laparoscopic (83.3%) or robotic (16.7%) abdominal assistance with a 9.2% conversion rate. Low anterior resection with sphincter salvage was achieved in 87% with 8 patients requiring intersphincteric resection. Anastomoses were hand-sewn in 57.4% and all patients were diverted. Median LOS was 5 days with a 42.6% 30-day morbidity rate and 3 postoperative mortalities (ARDS, pulmonary embolism and pseudomembranous colitis). Complete and near complete TME grade was achieved in 94.4% with a 3.7% rate of +CRM. At a median follow-up of 28 months, local and distant recurrence rates were 3.9% and 17.6%, respectively, with no cancer-related mortality.

CONCLUSION

Indications for taTME at experienced centers have expanded to include complex reoperative cases, local recurrences, metastatic cancer, and tumors with threatened CRM or IAS with evidence of post-treatment tumor regression. In the latter cases, taTME achieves good short-term outcomes and may facilitate R0 resection.