Left–right asymmetry in pelvic lymph nodes distribution: Is there a right-side prevalence?

ObjectiveTo assess whether pelvic lymph nodes have a left–right asymmetric distribution.Study designThe oncologic databases of two gynecologic academic departments were used to identify consecutive patients undergoing pelvic systematic lymphadenectomy as part of the treatment for a variety of gynecologic malignancies. All procedures were carried out in a standardized fashion. Lymph node counts were retrieved from pathological reports.ResultsFour hundred and twenty-eight women underwent pelvic lymphadenectomy during the study period. The median lymph node count was higher on the right side than on the left side [10 (0–33) versus 8 (0–29); P < 0.0001]. A prevalence of right-sided nodes was found in 265 (61.9%) patients, while in 44 (10.3%) cases pelvic nodes were equally distributed on the two sides. The right-sided prevalence was significantly higher than the expected 50% in each type of malignancy and surgical technique subgroup. The right-sided prevalence was statistically significant even when the analysis was performed for different nodal groups [external iliac nodes: 5 (0–23) versus 4 (0–13), P = 0.005; hypogastric and obturator nodes: 6 (0–17) versus 5 (0–19), P = 0.04]. Moreover, nodal count was higher on the right than on the left in obese [10 (1–33) versus 8 (1–26), P = 0.0002] and nonobese women [10 (0–32) versus 9 (0–29), P < 0.0001].ConclusionOur findings suggest the existence of a left–right asymmetry in pelvic lymph nodes distribution, with right-sided prevalence.