Prognostic Significance of Lateral Pelvic Lymph Node Dissection for Middle-Low Rectal Cancer Patients with Lateral Pelvic Lymph Node Metastasis: A Propensity Score Matching Study

Abstract

BackgroundThere is still controversy regarding whether the addition of lateral pelvic lymph node dissection (LPND) to total mesorectal excision (TME) confers survival benefits to rectal cancer patients with clinical lateral pelvic node metastasis (LPNM). MethodsPatients who underwent TME+LPND were systematically reviewed and divided into the LPNM group (n=29) and the non-LPNM group (n=112). The LPNM group were further subdivided into a high-risk LPNM group (n=14) and a low-risk LPNM group (n=15). Propensity score matching (PSM) was performed to minimize selection bias.ResultsOf the 141 patients undergoing LPND, the local recurrence rate of patients with LPNM was significantly higher than that of patients without LPNM both before (27.6% vs. 4.5%, P=0.001) and after (27.6% vs 3.4%, P=0.025) PSM. Multivariate analysis revealed that LPNM was an independent risk factor for not only OS (HR: 3.06; 95% CI, 1.15–8.17; P=0.025) but also DFS (HR: 2.39; 95% CI, 1.18–4.87; P=0.016) in patients with LPNM after TME+LPND. When the LPNM group was further subdivided, multivariate logistic regression analysis showed that OS and DFS were significantly better in the low-risk group (obturator/internal iliac artery region and < 2 positive LPNs).ConclusionEven after LPND, LPNM patients have a high local recurrence rate and poor prognosis. Moreover, LPNM is an independent poor prognostic factor affecting OS and DFS after TME+LPND. However, LPND appears to confer survival benefits to specific patients with single LPN involvement in the obturator region or internal iliac vessel region.