Initial experience with the transanal approach for lateral pelvic lymph node dissection in rectal cancer

Background: The efficacy and safety of transanal lateral pelvic lymph node dissection (TaLPLND) in rectal cancer has not yet been clarified. The aim of the present study was to evaluate the short-term results as an initial experience of TaLPLND.

Methods: This retrospective study included patients with middle to lower rectal cancer who underwent TaLPLND from July 2018 to July 2021. Our institutions targeted lymph nodes in the internal iliac area and the obturator area for lateral pelvic lymph node dissection (LPLND).

Results: A total of 30 consecutive patients with rectal cancer were included in this analysis. The median age was 60 years (range, 36-83 years), and the male-female ratio was 2:1. The median operative time was 362 min (IQR, 283-661 min), and the median intraoperative blood loss was 74 ml (IQR, 5-500 ml). Intraoperative blood transfusion was required in one case. No cases required conversion to laparotomy. TaLPLND was performed bilaterally in 13 patients (43.3%). Five patients (16.7%) underwent LPLND with combined resection of the internal iliac vessels. The median distance of the distal margin from the anal verge was 20 mm. The pathological radial margin (pRM) was positive in one case, and the negative pRM rate was 96.7%. Short-term postoperative complications (Clavien-Dindo classification grade ≥ II) were observed in nine cases (30.0%). There were no cases of reoperation or mortality. The median number of harvested lateral pelvic lymph nodes was 11 (range, 3-28). On pathological examination, lateral pelvic lymph nodes were positive for metastasis in seven cases (23.3%).

Conclusions: TaLPLND appeared to be beneficial from an oncological point of view because it was close to the upstream lymphatic drainage from the tumor. The short-term outcomes of this initial experience indicate that this novel approach is feasible.