Robotic extended pelvic lymphadenectomy for intermediate- and high-risk prostate cancer

Background: Accurate staging of prostate cancer is enhanced by a thorough evaluation of the pelvic lymph nodes. Limited data are available regarding robotic extended pelvic lymphadenectomy (PLA) in this setting.

Objective: Analyze our experience performing robotic extended PLA.

Design, setting, and participants: A total of 143 consecutive men with intermediate- or high-risk clinically localized adenocarcinoma of the prostate underwent robotic extended PLA and radical prostatectomy between September 2010 and November 2011 by a single surgeon.

Surgical procedure: Lymph node packets were sent separately from bilateral common, external, and internal iliacs, obturators, node of Cloquet, and anterior prostatic fat.

Measurements: Descriptive statistics were used to summarize lymph node yields and positive nodes. Clinical variables were examined in logistic regression models to predict lymph node positivity.

Results and limitations: Median lymph node yield was 20 (range: 9-65, interquartile range: 15-25). Eighteen patients (13%) were found to have metastatic prostate cancer in the lymph nodes. The mean number of positive nodes found was 2.9 (range: 1-11). In 14 of 18 node-positive patients (78%), the extent of nodal invasion was outside the boundaries of a limited PLA. For four patients with positive nodes (22%), prostate biopsy predicted unilateral disease but PLA revealed contralateral positive lymph nodes. A total of 82% of patients experienced no complications, and most Clavien grade 1-2 complications consisted of anastomotic leakage, urinary retention, ileus, and lymphocele. Only 4% of patients experienced a grade 3 complication. Under multivariate regression analysis, prostate-specific antigen (PSA), clinical stage, and maximum biopsy core tumor volume were identified as significant predictors of finding positive pelvic lymph nodes (area under the curve: 91%). The main limitations include short follow-up and lack of randomization.

Conclusions: Robotic extended bilateral PLA for prostate cancer up to the common iliac bifurcation increases nodal yield and positive nodal rate and can be performed safely. PSA, clinical stage, and maximum biopsy core volume are predictors for lymph node invasion. Long-term follow-up is needed to evaluate for therapeutic benefit.