A “proteomic-based” test for prostate cancer prognostic risk

Yet another new test will soon be available that claims to be able to differentiate with relative accuracy between clinically significant and clinically insignificant types of prostate cancer (again based on actual prostate cancer tissue from a biopsy sample or a surgical specimen).

The so-called ProMark™ test (available through a company called MetaMark) claims to be “the first and only proteomic-based imaging biopsy test” for prostate cancer.

In data presented by Saad et al. in a poster presented on Monday afternoon at the American Society for Clinical Oncology (ASCO) annual meeting in Chicago (see abstract no. 5090), the authors reported that:

  • Risk scores based on the ProMark test “were strongly predictive” of prostate cancer pathology.
  • The test could discriminate between “favorable” (i.e., post-surgical Gleason score 3 + 3 = 6 or 3 + 4 = 7; pathological stage ≤ pT2) and “non-favorable” (i.e., post-surgical Gleason score ≥ 4 + 3 = 7; pathological stage ≥ T3a, N+, or M+) cases
  • A ProMark risk score of < 0.33 had a predictive value of 81 percent for “favorable” disease (with a specificity of 90 percent).
  • A ProMark risk score of > 0.8 had a predictive value of 77 percent for non-favorable disease.
  • The test “provides improved personalized disease prediction relative to standard risk stratification systems” (such as the D’Amico and NCCN risk stratification systems).

Media information was also released by the company.

As with all the other tests that are now reaching the market (Oncotype DX, Prolaris, 4Kscore, phi, etc.) what we still don’t know is how well they stack up against each other or how good they are at projecting real-life outcomes at 10 years. In other words, we don’t have any real certainty about whether decisions to opt for treatment or expectant management (e.g., active surveillance) will be reliably accurate at 10 years of follow-up if we use one or more of these tests to help us make decisions like this. They may well be able to, but we just don’t know, and we have no idea which of all these tests might do this the best.

Of course the other factor relevant to all the genomic and proteomic tests is that they are only as good as the biopsy tissue used to run the tests. In other words, if the biopsy misses higher-grade cancer, the test may well tell you and your doctor that you have low-risk disease when you really have high-risk disease that simply hadn’t been found on biopsy.

While it is most certainly gratifying to see all these new types of test coming to the market, it is clearly going to be a while before we can tell how to apply any one (or several) of them with a highly predictable level of value.

2 Responses

  1. When looking at the choice of immediate treatment or active surveillance, isn’t blurry vision better than blind?

  2. Mike: See the data just reported about the phi test.

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