J. W. Yaxley, J. Dagher, B. Delahunt, L. Egevad, J. Srigley, H. Samaratunga

Performing an extended pelvic lymph node dissection (PLND) on all men with intermediate- and high-risk prostate cancer at the time of a radical prostatectomy (RP) remains controversial. The majority of patients PLND histology is benign, and the long-term cancer-free progression in men with positive lymph node metastasis is low. The objective is to investigate the probability of long-term biochemical freedom from recurrent disease (bNED) in men with lymph node metastasis identified at the time of radical prostatectomy (RP). A retrospective review of the pathology of 1184 pelvic lymph node dissections performed at the time of a radical prostatectomy by multiple surgeons referred to a single uro-pathology laboratory between 2008 and 2014 identified 61 men with node-positive prostate cancer. Of the men with positive nodes, 24 had a standard PLND and 37 an extended PLND (ePLND). bNED was defined as a post-operative serum PSA < 0.2 ng/ml. The median follow-up is 4 years (2-8). The median lymph node count was 7 (range 2-16) for PLND and 22 (range 6-46) for the ePLND. A single lymph node metastasis was identified in 56% of the 61 men. Only 10% of men with a positive lymph node metastasis remained free of biochemical recurrence of disease, and only 5% had undetectable serum PSA. There was no difference in bNED outcome between a PLND and ePLND. The number of men needed to be treated with a PLND at the time of RP (NNT) to result in an undetectable post-operative PSA at a median follow-up of 4 years is 395. In men with lymph node metastasis, the probability of long-term bNED is low and the NNT for cure is high. With emerging improved radiological imaging techniques increasing the detection of lymph node metastasis outside the extended lymph node dissection templates, more scientific investigation is required to evaluate which men will benefit from a PLND and which men can avoid an unnecessary PLND procedure.