Case Discussion: The Role Of Lymphandectomy In Early Prostate Cancer
December 21, 2017
UroToday - A case discussion took place at the plenary session at the EAU meeting. It addressed the role of lymphadenectomy (LA) in prostate cancer (CaP). Professor Tombal (Brussels) chaired the session that included Drs. Studer (Berne), Touijer (NY), Wechermann (Augsburg), and Wiegel (Ulm). The discussion and cases addressed a multi-disciplinary approach to diagnosis and management.
In the first case, a 58 year old man with a PSA of 13ng/ml had a biopsy showing Gleason score 6 CaP in 4 cores, 10-25% involvement per core. His PSA was 6.5ng/ml one year earlier, but no biopsy was offered. The audience voted that for staging, they preferred a nomogram over MRI, CT, or PET. The nomogram most preferred was the Partin, over the Kattan and Briganti. Dr. Touijer commented that the risk of LN involvement in this patient is about 3%. He also reviewed the concept of how prediction models are made, basing nomograms on a large set of previous patient outcomes in a database. The purpose is to use objective data as opposed to individual physician anecdotal experience. The problem, he added is that nomograms base present patient decisions on past patient databases. This can be influenced, for example by shifts in tumor grade and stage and does not take into account improvement in surgeon technique. However, despite nomograms the surgeon decides on whom a LA should be performed. For example, with a 2% risk of cancer not performing a LA could have a 12% chance of missing cancer.
PET CT scanning has only a 55% negative predictive value and does not do a good job detecting LN's smaller than 5mm. MRI with super paramagnetic iron oxide is significantly better, but still has limitations for small LN's. The point was made that the expertise of the radiologist influences these outcomes. The conclusion was that CT, MRI and PET/CT are presently not the standard for staging CaP LN.
Dr. Weckermann presented the technique of injecting radioactive tracers into the prostate and scanning the sentinel LN. If the sentinel LN is negative, then secondary LN's are negative and this correlation is also true for positive LN. Using this technique in over 1,000 patients prior to LA, they found a 19.6% positive LN rate. The false negative rate was 1% with 205 of 207 men with a positive sentinel LN have CaP detected by the test. She concluded that when the non-sentinel LN's are positive, then an extended LN dissection should be done.
After hearing this data with a nomogram risk of positive LN's being 2%, the audience voted 55% in favor of limited LA, 22% an extended LA and the rest would not perform a LA. Dr. Studer pointed out that in patients with minimal CaP that likely do not need a radical prostatectomy then a LA is not relevant. He showed data that nomograms are not based upon adequate LA data. SEER data showed that even patients with negative LN on LA had better survival than those without having a LA. This suggests that microscopic CaP exists that is not detected on initial pathologic analysis and this negatively affects their survival. Dr. Studer projected an image of what an extended LA should look like when completed. Dr. Touijer showed that laparoscopic LA could be applied to do a limited or standard LA. They acquired 10.1 LN with the limited and 14 with the standard LA. He compared the laparoscopic to the open RP experience at MSKCC and the positivity rates were slightly better in the lap group. The LA in the laparoscopic patients added 55 minutes to the operative time. The complication rate also increased, but it was mostly minor complications. While the majority of the audience voted that they would abort the RP if any LN were positive, the panel was in favor of completing the operation. Dr. Touijer stated that up to 30% of frozen sections are not accurate and that is one reason to continue. Others stated that proceeding improves overall outcome and local control. Dr. Wiegel showed the argument for giving adjuvant radiotherapy for this case of finding 2 positive LN at surgery. Dr. Weckermann did not think that every patient in this setting should receive adjuvant androgen deprivation therapy. This is because the Messing data was not in the PSA era. In the Berne data, 39% of patients with one positive LN did not progress and this was 12.2% if 2 LN's were positive. Dr. Studer was in favor of giving adjuvant androgen deprivation to patients with a PSADT of