Predictive factors of pathological lateral pelvic lymph node metastasis in patients with selective laparoscopic lateral lymph node dissection for rectal cancer:A retrospective Study

Abstract

Abstract Background:In recent years, selective lateral lymph node dissection（LLND） has been recognized by more and more surgeons.However, the indication for this procedure remains unclear. Purpose: We aimed to identify the predictive factors for pathological lateral pelvic lymph nodes metastasis(LPNM) and the indications for lateral pelvic lymph node dissection. Methods: This study involved 55 patients with locally advanced rectal cancer and clinically suspected lateral pelvic lymph nodes(LPN) metastasis who underwent total mesorectal excision（TME）with LLND between December 2019 and October 2023. According to pathological findings, they were divided into negative LPN (n=35) and positive LPN(n=20) groups. Primary endpoints were overall pathologic positive rate and risk factors of pathological LPNM. Results: Among 55 patients, 20 (36.4%) had pathologically confirmed lateral pelvic lymph node metastasis. Initial short-axis diameter of LPN (≥7mm,p=0.003), imagie risk factors (≥3,p=0.008), LLND time (heterochronism,p=0.014),distant metastasis(yes,p=0.005) and p-N stage(N2,p＜0.001) were significantly associated with pathological LPNM. Initial short-axis diameter of LPN (p=0.012,OR 12.732,95%CI 1.768-91.699) and p-N stage(p=0.010,OR 13.650,95%CI 2.658-95.380) were independent risk factors for pathological LPNM in multivariable analysis furtherly. Conclusion: Initial short-axis diameter of LPN and p-N stage were significant predictors of lateral pelvic lymph node metastasis. This study recommended that initial short-axis diameter of LPN ≥7 mm as a Cut-off value for selective LLND.