Systematic Lymphadenectomy for Survival in Patients with Endometrial Cancer: A Meta-analysis

The efficacy of systematic lymphadenectomy is controversial for improving overall survival in patients with endometrial cancer. Thus, we performed a meta-analysis comparing the efficacy for overall survival between systematic and unsystematic lymphadenectomies. After an extensive literature search between January 2000 and August 2010, we analyzed nine studies (two randomized controlled trials and seven observational studies) involving 16 995 patients with endometrial cancer. Systematic versus unsystematic lymphadenectomy was defined using two criteria: removal of epsilon 1011 versus 1011 lymph nodes; systematic dissection of lymphatic tissues versus no lymphadenectomy other than suspicious lymph nodes. In all studies, systematic lymphadenectomy improved overall survival, compared with unsystematic lymphadenectomy (hazard ratio, 0.89; 95 confidence interval, 0.820.97), whereas its efficacy was not shown in two randomized controlled trials (hazard ratio, 1.05; 95 confidence interval, 0.841.31). Removal of epsilon 1011 lymph nodes improved overall survival, compared with that of 1011 lymph nodes (hazard ratio, 0.88; 95 confidence interval, 0.810.97) in spite of no difference in overall survival between systematic dissection of lymphatic tissues and no lymphadenectomy other than suspicious lymph nodes (hazard ratio, 0.94; 95 confidence interval, 0.771.15). Furthermore, systematic lymphadenectomy increased overall survival in patients with intermediate- or high-risk endometrial cancer (hazard ratio, 0.77; 95 confidence interval, 0.700.86) in spite of no efficacy in those with low-risk endometrial cancer (hazard ratio, 1.14; 95 confidence interval, 0.871.49). These findings suggest that the efficacy of systematic lymphadenectomy, defined as removal of more than about 10 lymph nodes, is limited for improving overall survival in patients with low-risk endometrial cancer, whereas it is efficient to increase overall survival in patients with intermediate- or high-risk endometrial cancer.