Category: Imaging & Image Guided Therapy: New Therapies
Introduction & Objective :
PSMA-PET based imaging is increasingly being studied to improve diagnosis and staging of prostate cancer in addition to localizing recurrences to direct salvage therapies. Little is known about predictors of PSMA-PET SUV intensity in either primary disease or recurrences; our goal was to evaluate predictors of genomic expression of PSMA.
The de-identified GenomeDx database, which includes more than 7,000 men who underwent prostatectomy, was queried in November 2017 for expression of FOLH1 (PSMA). Each patient has the genetic markers of more than 46,000 coding and noncoding genes prospectively recorded in the database. PSMA expression was compared to the Decipher Risk Group (A validated a 22biomarker genomic score), luminal vs basal genomic subtype, and the Gleason grade using Student’s T-test.
The database contained 1,087 Gleason 3+3 patients and 6,613 Gleason 3+4 patients. The median FOLH1 score was higher for 3+4 when compared to 3+3 (0.85 vs. 0.68, p<0.001). FOLH1 expression was also higher in Gleason 4+3 compared to 3+4 (~1.0 vs. 0.85). FOLH1 expression was also predicted by Decipher Risk Group: low = 0.79 vs. average = 0.86 vs. high = 0.94 (p <0.001). FOLH1 was higher in luminal vs. basal in both Gleason 3+3 (0.77 vs. 0.50, p <0.001) and 3+4 (0.92 vs. 0.62, p <0.001).
PSMA expression (FOLH1) was predicted by Decipher Risk Group, Gleason grade, and basal vs. luminal subtyping. Genomic tests could predict the ability of PSMA-PET to accurately image prostate cancer.
Clinton Bahler– Assistant Professor, Indiana University, Indianapolis, Indiana
Melissa Johnson– Indiana University, Indianapolis, Indiana
Jason Alter– Director, GenomeDx, San Diego, California
Mark Green– Professor, Indiana University, Indianapolis, Indiana
Michael Koch– Professor and Chair, Indiana University, Indianapolis, Indiana