How can we predict lymphorrhoea and clinically significant lymphocoeles after radical prostatectomy and pelvic lymphadenectomy? Clinical implications

OBJECTIVE To identify clinical and pathological variables that may help clinicians in predicting, preventing and managing lymphorrhoea and clinically significant lymphocoeles (CSL), which are reported complications after pelvic lymphadenectomy (PLND) and retropubic radical prostatectomy (RRP). PATIENTS AND METHODS We prospectively analysed 552 consecutive men with prostate cancer who underwent RRP and PLND (2006-2008). All patients had detailed clinical and pathological data prospectively recorded in an electronic database. Drains were removed when the amount of lymph was < 20 mL in the previous 24 h. A CSL was defined as the presence of a symptomatic lymphocoele requiring treatment. Lymphorrhoea was defined as the total amount of lymph drained by the drains until their removal. Univariable and multivariable logistic regression models were used to test the association between all the predictors (age, body mass index, American Society of Anesthesiologists score, prostate volume, clinical stage, number of LNs removed, surgeon, pathological T and N stage) and the presence of CSL. Univariable and multivariable linear regression models were also used to test the association between the available predictors and lymphorrhoea. RESULTS The median (range) number of LNs removed was 20 (1-63). Both linear and logistic multivariable regression analysis showed that the number of removed LNs and age were the only two statistically significant predictors of total amount of lymphorrhoea and CSL after RRP and PLND (both P < 0.01). Specifically, the risk of developing a CSL increased by 5% for every LN removed. Similarly, every year of age increased the risk of having CSL by 5%. The most informative thresholds for predicting CSL were 65 years of age and 20 LNs removed. External iliac lymphadenectomy resulted in a higher associated risk of lymphorrhoea and CLS relative to obturator LN removal (P = 0.001 vs P = 0.1, respectively). CONCLUSIONS There was a positive association between the number of LNs removed and age at RRP with the amount of lymphorrhoea and the risk of developing a CSL. The most informative thresholds in predicting CSL were 65 years of age and 20 LNs removed. External iliac lymphadenectomy resulted in a higher risk of lymphorrhoea and CLS relative to obturator LN removal.