The Association Between Total and Positive Lymph Node Counts, and Disease Progression in Clinically Localized Prostate Cancer

Abstract

We examined the association between the number of LNs removed, the number of positive LNs and disease progression in patients undergoing pelvic lymph node dissection and radical retropubic prostatectomy for clinically localized prostate cancer. We analyzed 5,038 consecutive patients who underwent radical retropubic prostatectomy between 1983 and 2003. Clinicopathological parameters, including the administration of neoadjuvant hormonal therapy, preoperative prostate specific antigen, specimen Gleason score, surgeon and pathological stage, were collected prospectively in our prostate cancer database. We excluded men treated with radiation or chemotherapy before surgery. BCR was defined as 2 postoperative prostate specific antigen increases greater than 0.2 ng/ml. Cox models were used to determine whether the number of nodes removed or the number of positive nodes predicted freedom from BCR after adjustment for prognostic covariates. The 4,611 eligible patients had a median of 9 LNs (IQR 5 to 13) removed. Positive nodes were found in 175 patients (3.8%). Overall the number of LNs removed did not predict freedom from BCR (HR per additional 10 nodes removed 1.02, 95% CI 0.92 to 1.13, p = 0.7). Results were similar in patients receiving and not receiving neoadjuvant hormonal therapy. Finding any LN involvement was associated with a BCR HR of 5.2 (95% CI 4.2 to 6.4, p <0.0005). However, in men without nodal involvement an increased number of nodes removed correlated significantly with freedom from BCR (p = 0.01). Nodal disease increased the risk of progression. Extensive lymphadenectomy enhances the accuracy of surgical staging. However, we were unable to determine that removing more nodes improves freedom from BCR uniformly. Since the proportion of patients with prostate cancer with positive nodes is low, the value of extensive lymphadenectomy requires a multi-institutional, randomized clinical trial.