Size and volume of metastatic and non-metastatic lymph nodes in pelvis and lower abdomen in patients with carcinoma of the bladder undergoing radical cystectomy

Objective. This study aimed to evaluate the usability of size and volume of lymph nodes (LNs) in the pelvis and lower abdomen to predict metastatic disease in patients with carcinoma of the urinary bladder. Material and methods. LNs retrieved from 177 patients undergoing radical cystectomy and extended LN dissection were prospectively registered with number, location, presence of metastatic disease, longitudinal length, transverse diameter and a calculated LN volume. Results. A mean of 21.2 LNs was removed from each patient. Thirty-eight patients (21.5%) had positive LNs. The total LN volume per patient was independent of the number of LNs removed, whereas mean volume per LN was inversely proportional to the number of LNs removed in node-negative patients, suggesting a physiological variation in the number of pelvic LNs. Positive LNs were generally larger than negative LNs. This difference was more pronounced using the transverse diameter than using longitudinal length. Calculated higher volume of an LN was also associated with an increased risk of metastases. However, no optimal cut-off values predicting metastatic disease based on LN size were found owing to low sensitivity and low predictive value at the tested cut-off values. The size difference comparing positive and negative LNs was therefore not clinically applicable as an overall preoperative risk estimation of metastatic disease. Conclusions. A fixed volume of lymphatic tissue rather than a fixed number of LNs seems to be present in node-negative patients. Size of LNs remains a poor predictor of metastatic disease in bladder cancer.