What is the number of lymph nodes required for an "adequate" pelvic lymphadenectomy?

Purpose of investigation: To establish a definition of an adequate number of lymph nodes identified at a pelvic lymphadenectomy through statistical methods. Methods: We conducted a retrospective study in cervical and endometrial carcinoma patients who underwent radical or staging surgery. The Student's t-test, Pearson's correlation, analysis of variance, and linear regression analysis were used. Results: Five hundred and ninety four-sided pelvic lymphadenectomies were analyzed. The mean (range) number of pelvic lymph nodes identifed was 11.3 (0-42). The 1^st, 5^th and 10 ^th percentiles were three, five, and six lymph nodes respectively. The number of lymph nodes was higher in the laparoscopic approach compared to laparotomy (11.9 vs 10.6, p < 0.01). Conclusions: The number of lymph nodes identified at a pelvic lymphadencetomy vary with type of surgery. We propose that using the 1^st, 5^th of 10^th percentile is reasonable for the definition of an adequate number of lymph nodes to be identified at a pelvic lymphadenectomy.