Clinicopathological Characteristics and Survival Prognosis Analysis of 102 Rectal Cancer Patients with Lateral Pelvic Lymph Node Metastases

Objective To investigate the therapeutic effect and prognostic significance of lateral lymph node dissection (LPLND) in patients with lateral lymph node (LPLN) metastasis. Methods The clinicopathological data of rectal cancer patients who underwent total mesorectal excision (TME) combined with LPLND and pathologically confirmed as LPLN metastasis after operation were retrospectively analyzed. The clinicopathological characteristics and metastasis rules of patients with LPLN metastasis were discussed, and the survival prognosis after LPLND was analyzed. Results A total of 102 rectal cancer patients with pathologically confirmed LPLN metastasis were included. The common sites of LPLN metastasis were internal iliac vessels lymph nodes (n=68, 66.7%), followed by obturator lymph nodes (n=44, 43.1%), and common iliac vessels or external iliac vessels lymph nodes (n=12, 11.8%). There were 10 patients (9.8%) with bilateral LPLN metastases, and the mean number of LPLN metastases was 2.2±2.4, among which 16 patients (15.7%) had LPLN metastases number≥2. The 3-year OS (66.8% vs. 7.7%, P < 0.001) and DFS (39.1% vs. 10.5%, P=0.012) of patients with LPLN metastases to the external iliac or common iliac lymph node were significantly lower than those with metastases to the internal iliac or obturator lymph node. The multivariate analysis showed that LPLN metastasis to external iliac or common iliac lymph node was an independent risk factor both for OS (HR=3.53; 95%CI: 1.50-8.31; P=0.004) and DFS (HR=2.40; 95%CI: 1.05-5.47; P=0.037). Conclusion LPLN mainly metastasizes to the internal iliac or obturator lymph node areas. The survival of patients with metastasis to the external iliac or common iliac lymph node cannot be improved by LPLND, and thus systemic comprehensive treatment is often the optimal treatment option.