Feasibility, Indications, and Prognostic Significance of Selective Lateral Pelvic Lymph Node Dissection After Preoperative Chemoradiotherapy in Middle/Low Rectal Cancer: Results of a Multicenter Lateral Node Study in China

BACKGROUND: Lateral pelvic lymph node dissection after preoperative chemoradiotherapy can decrease local recurrence to lateral compartments, thereby bringing survival benefits. OBJECTIVE: The safety of lateral pelvic lymph node dissection after preoperative chemoradiotherapy was investigated, and the surgical indications and survival benefits of lateral pelvic lymph node dissection were established based on preoperative characteristics. DESIGN: A multicenter retrospective study. SETTINGS: Three hospitals in China. PATIENTS: Four hundred nine patients with clinical evidence of lateral pelvic lymph node metastasis. INTERVENTIONS: Patients who received lateral pelvic lymph node dissection were divided into two groups depending on whether they received chemoradiotherapy (n = 139) or not (n = 270). MAIN OUTCOME MEASURES: The safety, indications, and survival benefits of lateral pelvic lymph node dissection after preoperative chemoradiotherapy were investigated. RESULTS: The surgery times were significantly prolonged by preoperative chemoradiotherapy (291.3 vs. 265.5 min, p = 0.021). Multivariate analysis demonstrated that poor/mucinous/signet-ring adenocarcinoma (odds ratio=4.42, 95% confidence interval, 2.24–11.27; p = 0.031) and post-chemoradiotherapy lateral pelvic lymph node short-axis diameter ≥7 mm (odds ratio=15.2, 95% confidence interval, 5.89–53.01; p < 0.001) were independent predictive factors for lateral pelvic lymph node metastasis. Multivariate prognostic analysis showed that swollen lateral pelvic lymph nodes beyond the obturator or internal iliac as well as the involvement of three or more lateral pelvic lymph nodes were independent adverse prognostic factors. LIMITATIONS: The retrospective nature of the study and the small sample size. CONCLUSIONS: Preoperative chemoradiotherapy combined with lateral pelvic lymph node dissection is a practicable procedure with acceptable morbidity. Post-chemoradiotherapy lateral pelvic lymph node short-axis diameter ≥7 mm and poor/signet/mucinous adenocarcinoma could be used for predicting lateral pelvic lymph node metastasis after chemoradiotherapy. However, lateral pelvic lymph node dissection should be carefully considered in patients with swollen lateral pelvic lymph nodes beyond the obturator or internal iliac region or involvement of multiple lateral pelvic lymph nodes. See Video Abstract at http://links.lww.com/DCR/C133.