AUA 2018: Is Prostate Cancer Screening and Risk Stratification Moving Beyond the PSA Test?

New diagnostic tests for prostate cancer, as well as new information about the impact of the U.S. Preventive Services Task Force recommendations on prostate cancer screening, were presented at the 113th Annual Meeting of the American Urological Association (AUA).

PSA Screening of African American Veterans Before, During, and After Implementation of the 2012 USPSTF Recommendations

Prostate cancer screening rates at Department of Veterans Affairs' (VA) clinics declined for both African American and non–African American men following the release of the 2012 prostate cancer screening recommendations from the U.S. Preventive Services Task Force (USPSTF), according to this multi-institutional study (Abstract PD52-11).

Researchers examined prostate-specific antigen (PSA) screening rates for male veterans aged 40 to 80 without a diagnosis of prostate cancer who visited a VA primary care or urology clinic between 2009 and 2016 and assessed the differential effect of the USPSTF policy change on screening rates. Results were assessed for the pre-guidelines period (2009–2010), the transition period (2011–2014), and the post-guideline period (2015–2016).

They showed:

  • Prior to the release of the USPSTF recommendations, African American veterans underwent PSA screening more often at the VA than non–African American veterans. However, across the years of the study, the percentage of PSA-eligible men who received a test decreased yearly (from 63% in 2009 to 51% in 2016).
  • PSA screening rates in the pre-guidelines period show a 6% decrease for African American veterans and a 6.3% decrease for non–African American veterans.
  • During the transition period, the screening rate for African American veterans decreased by 12.7%, and the rate for non–African American veterans decreased by 12.8%.
  • During the post-guideline period, screening rates continued to decrease, with African American veterans experiencing a 3.5% decrease and non–African American veterans a decrease of 3.6%.

Prostate Cancer Genomics

The use of genomic tests to predict outcomes and guide treatment for prostate cancer is growing, but discrepancies exist between these tests and their recommendations for treatment vs active surveillance (AS). Researchers reviewed three unique tests (Decipher, Prolaris, and Oncotype DX) to evaluate genomic test results and the potential implications of their results on eligibility for AS (Abstract PD06-09).

By performing a retrospective chart review, researchers identified 22 patients who underwent at least two of these genomic tests at Hartford Hospital between 2014 and 2017. Results were compared to genomic standards for AS appropriateness based on guidelines from the National Comprehensive Cancer Network (NCCN). Percentage agreement rates were calculated, and kappa statistic (k) was used to obtain proportion of agreement over and above chance.

Results showed:

  • AS would be recommended for 21 out of 22 patients based on NCCN guidelines.
  • For the 12 patients who received both the Decipher and Prolaris tests, percentage agreement was 67% and k was 0.31 (P = .276).
  • For the 8 patients who received Prolaris and Oncotype DX, percentage agreement was 75% and k was 0.39 (P = .168), with Prolaris tending to favor AS over surgery.
  • 2 patients received both Decipher and Oncotype DX. These tests together yielded a 50% agreement and an incalculable k.
  • When compared to NCCN guidance, Prolaris had a 75% agreement and .21 k (P = .117, n = 20); Decipher had a 60% agreement and k of .15 (P = .268, n = 15); and Oncotype DX had an agreement of 50% with an incalculable k.

Novel Urine Exosome Gene Expression Assay to Predict High-Grade Prostate Cancer at Initial Biopsy

A new class 3-gene expression urine assay for prostate cancer—ExoDx Prostate IntelliScore, or EPI—may help identify patients with higher grade disease and could help reduce unnecessary biopsies. This extended validation study assessed outcome and cut-point performance for EPI test results compared with biopsy outcomes (Abstract MP40-10).

The validation cohort was comprised of 504 men with a mean age of 64 years and a mean PSA of 5.6 ng/mL. Fifty-three percent of the men had a positive biopsy, with 22% having a Gleason score of 6, 17% having a Gleason score of 3+4, and 14% having a Gleason score of 4+3.

Results showed:

  • Using ROC analysis, the EPI AUC was 0.70, compared to AUC of 0.62 for standard of care (PSA, age, race, family history) for discriminating high-grade disease from low-risk/benign disease.
  • Using the (previously validated) cut point of 15.6 (or alternative 20) would avoid 26% (or 40%) of unnecessary prostate biopsies, and 20% (or 31%) of total biopsies, with a negative predictive value of 89% for both cut points.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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