SIU 2017: PSMA Positivity in Metastatic Prostate Cancer: A Morphological Bias?

Lisbon, Portugal ( PSMA-PET Scan is becoming increasingly popular in the setting of biochemical recurrence after PCa definitive therapy (XRT or RP) for identification of low-volume metastatic disease. However, while better than conventional imaging, it is not perfect.

In this study, the authors attempt to correlate PSMA PET avidity to PCa histology. To that effect, they assessed retrospectively a patient cohort who had undergone salvage template pelvic lymph node dissection for oligometastatic disease following definitive local therapy and BCR.

Of 66 patients with BCR, 20 were found to be PSMA PET avid and underwent salvage LND. Mean PSA was 2.49 at the time of oligometastatic diagnosis. All 20 were found to have metastatic prostate cancer at the time of diagnosis. 16 of the 20 patients had exhibited prominent cribriform architecture, and 11 had 100% cribriform pattern. In particular, this was most commonly seen with ductal adenocarcinoma or acinar adenocarcinoma.

While interesting, obviously this represents a small series. This would be interesting to compare to series in which PSMA was completed prior to prostatectomy and see if similar results were found. Also interesting is the finding of ductal adenocarcinoma, as this tends to be an aggressive disease, sometimes without much PSA rise. Future follow-up from this study will be valuable.

Speaker(s): Daniel Christidis, Australia

Institution(s): Austin Hospital, Australia

Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, twitter: @tchandra_uromd, at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal