Feasibility, Indications and Prognostic Significance of Selective Dissection after Preoperative Chemoradiotherapy in Middle/Low Rectal Cancer with Clinical Suspected Lateral Pelvic Lymph Node Involvement: Results of the Multicenter Lateral Node Study in China

Abstract

Background: It is believed that selective lateral lymph node (LPN) dissection (LPND) with total mesorectal excision after preoperative chemoradiotherapy can reduce lateral compartment recurrence and improve survival in rectal cancer patients with LPN metastases. We evaluated the feasibility, optimal indications, and prognosis of LPND after preoperative chemoradiotherapy in patients with rectal cancer.Methods: This was a multicenter retrospective study which included patients with rectal cancer and clinical evidence of LPN metastases (n = 466) treated across three hospitals in China. The patients who underwent the combined procedure were categorized into chemoradiotherapy (n = 155) and non-chemoradiotherapy (n = 291) groups.Results: Preoperative chemoradiotherapy significantly prolonged surgical duration (300.7 vs. 277.4 min, P <0.001). In a multivariate logistic regression analysis, a post-chemoradiotherapy LPN short-axis diameter ≥7 mm and poor/mucinous/signet adenocarcinoma were independent risk factors for pathological LPN metastasis after chemoradiotherapy. Overall survival (P <0.001) and disease-free survival (P <0.001) were significantly worse in patients with LPN, which was however not an independent risk factor for survival after eliminating confounders. Multivariate prognostic analysis conducted in a subset of 40 patients with pathological LPN metastasis showed that distant metastasis, metastasis beyond the obturator or internal iliac region, and more than one LPN metastasis were independent predictor of poor overall survival.Conclusions: Chemoradiotherapy with the combined procedure is safe and feasible with acceptable morbidity. A post-chemoradiotherapy short-axis LPN diameter ≥7 mm and poor/mucinous/signet adenocarcinoma can predict pathological LPN metastasis after chemoradiotherapy. However, LPND should be carefully considered in patients with distant metastases, metastases beyond the obturator or internal iliac region, and multiple LPN involvement.