Impact of Lateral Pelvic Lymph Node Dissection on the Survival of Patients with T3 and T4 Low Rectal Cancer.

ABSTRACT

BACKGROUND: The aim of this study was to clarify the survival benefit of lateral pelvic lymph node dissection (LPLND) for patients with pathological T3 and T4 (pT3/T4) low rectal cancer. METHODS: We evaluated the impact of LPLND on survival for pT3/T4 low rectal cancer patients. The primary endpoint of the study was overall survival (OS). The large-scale database of the Japanese Society for Cancer of the Colon and Rectum registration system was accessed and the data were analyzed using a propensity score matching method based on the likelihood of receiving LPLND. Using seven covariates, the propensity scores were calculated with multivariate logistic regression. A total of 499 propensity score-matched pairs of patients were selected from the entire cohort of 1,840 patients who had received curative resection for pT3/T4 low rectal cancer between 1995 and 2004. RESULTS: In the matched cohort, the 5-year OS of the patients who had and had not undergone LPLND were 68.9 and 62.0 %, respectively (p = 0.013; hazard ratio [HR], 0.755; 95 % confidence interval [CI], 0.604-0.944). The 5-year OS of the patients with node-negative disease who had and had not received LPLND differed statistically significantly (5-year OS were 82.1 and 71.4 %, respectively. p = 0.006; HR, 0.579; 95 % CI 0.389-0.862). However, those with node-positive disease did not differ significantly (5-year OS were 55.5 and 53.8 %, respectively. p = 0.415; HR 0.893; 95 % CI 0.681-1.172). CONCLUSIONS: The impact of LPLND on OS for patients with node-negative pT3/T4 low rectal cancer was suggested in this retrospective cohort study. To determine true benefits and harms of LPLND, further prospective studies may be warranted.