Nomogram predicting risk of lymphocele in gynecologic cancer patients undergoing pelvic lymph node dissection

OBJECTIVE The purpose of this study is to estimate the risk of postoperative lymphocele development after lymphadenectomy in gynecologic cancer patients through establishing a nomogram. METHODS We retrospectively reviewed 371 consecutive gynecologic cancer patients undergoing lymphadenectomy between 2009 and 2014. Association of the development of postoperative lymphocele with clinical characteristics was evaluated in univariate and multivariate regression analyses. Nomograms were built based on the data of multivariate analysis using R-software. RESULTS Mean age at the operation was 50.8±11.1 years. Postoperative lymphocele was found in 70 (18.9%) patients. Of them, 22 (31.4%) had complicated one. Multivariate analysis revealed that hypertension (hazard ratio [HR], 3.0; 95% confidence interval [CI], 1.5 to 6.0; P=0.003), open surgery (HR, 3.2; 95% CI, 1.4 to 7.1; P=0.004), retrieved lymph nodes (LNs) >21 (HR, 1.8; 95% CI, 1.0 to 3.3; P=0.042), and no use of intermittent pneumatic compression (HR, 2.7; 95% CI, 1.0 to 7.2; P=0.047) were independent risk factors for the development of postoperative lymphocele. The nomogram appeared to be accurate and predicted the lymphocele development better than chance (concordance index, 0.754). For complicated lymphoceles, most variables which have shown significant association with general lymphocele lost the statistical significance, except hypertension (P=0.011) and mean number of retrieved LNs (29.5 vs. 21.1; P=0.001). A nomogram for complicated lymphocele showed similar predictive accuracy (concordance index, 0.727). CONCLUSION We developed a nomogram to predict the risk of lymphocele in gynecologic cancer patients on the basis of readily obtained clinical variables. External validation of this nomogram in different group of patients is needed.