Oncological safety of transanal total mesorectal excision (TaTME) for rectal cancer: mid-term results of a prospective multicentre study

BACKGROUND: There is no consensus regarding the gold standard technique for rectal cancer as Total Mesorectal Excision (TME) may be safely performed either by open or minimally invasive surgery. The laparoscopic approach, however, may carry technical difficulties. For this reason, a novel technique has emerged in the last decade combining a dual laparoscopic dissection (abdominal and transanal) to perform the TME technique (TaTME). When focusing on oncological outcomes, there is a lack of literature regarding mid-long term results. The aim of this study is to evaluate the mid-term oncological impact of TaTME for treating rectal cancer. METHODS: A prospective multicentre study was performed in four tertiary centres including consecutive patients who underwent TaTME for mid-low rectal cancer by the same group of experienced surgeons. The analysed data included pathological results on the quality of TME and mid-term oncological outcomes. RESULTS: In total, 173 patients were included throughout a study period of 6 years. Our series included 70% males and 68% of patients with neoadjuvant treatments. The median follow-up was 23 [15-37.5] months. Regarding pathological results, a complete TME was achieved in 72.8%, while circumferential and distal margins were affected in 1.4 and 1.1%, respectively. Five patients developed local recurrences (3%) and 8.1% presented distant disease during the follow-up. The 2-year disease-free survival and the overall survival rates were 88% and 95%, respectively. CONCLUSIONS: There is currently a lack of evidence in the literature regarding TaTME and oncological outcomes with no data available from randomized clinical trials. In the meantime, the reported results from different multicentre series are controversial. This study showed positive mid-term outcomes at 2 years of follow-up and supported notable oncological outcomes with TaTME. However, it must be emphasized that previous experience in minimally invasive and transanal surgeries is essential for surgeons before intending to perform TaTME.