Predicting pelvic lymph node involvement in patients with localized prostate cancer

Pelvic lymph node dissection is a routine staging procedure in localized prostate cancer. It provides prognostic information, it influences the design of the subsequent therapeutic strategy and it provides information necessary to compare the results of various therapeutic strategies. It is not considered a curative procedure. Thanks to improved diagnostic means, the unexpected finding of positive lymph nodes has decreased from 30% 15 years ago to below 10%. Hence, today the procedure is unnecessary in over 90% of the cases. Improvements in staging by imaging techniques, including CT scan, MRI, ultrasound, and ileopelvic scintigraphy, have so far been unsuccessful because of low specificity and sensitivity. Using a combination of tumor grade and stage plus serum prostate-specific antigen (PSA) levels, a good indication of the likelihood of positive pelvic nodes can be obtained. A review of the literature indicates that for clinically localized tumors, i.e. stages T1a to T2b, lymph node dissection can be omitted provided serum PSA levels are < 10 ng/ml and the tumor is well to moderately well differentiated (Gleason grade < 7). Using these cutoff values, approximately 25% of our patients can be saved a pelvic lymph node dissection at the price of approximately 3% missed cases.