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Prolaris Genomic Test for Assessing Risk for Men with Localized Prostate Cancer

Overtreatment, and for that matter undertreatment, have been fairly constant concerns in relation to prostate cancer for some time. Considering this, it is really surprising that there is not more discussion of the role the Prolaris genomic test can play in determining the aggressiveness of prostate cancer and in choosing the most appropriate treatment. I had literally been working with the ProstateCancer.net community for well over a year before I came across a mention of it and then had to do some research in order to answer the individual inquiry about it.

What’s the Prolaris genomic test?

The test was released in 2010, yet there seems to be relatively little research available. The research that has been done appears to have quite positive results, however, the test does not seem to be widely utilized. Some of this may be due to cost, but the dearth of research may also be playing a role.8 The good news is that research is ongoing and may help push the test into more common usage.

The Prolaris genomic test estimates cell cycle progression (CCP), which is the rate that cells divide and multiply. All cancer has in common a loss of regulation of the rate of cell division. There are specific genes that control CCP. The Prolaris test looks at 31 of these genes to create a scale predicting the rate of division of the cancer cells and thus the estimate of the aggressiveness of the cancer.1

For men who have been diagnosed with low grade, low volume prostate cancer after utilizing the standard DRE, PSA, and biopsy, getting a prediction on the aggressiveness of the cancer can go a long way in helping determine whether to pursue active surveillance or immediate treatment. The test can be done from material already collected during the biopsy. The test is a little expensive at about $3,400 (although not so much when compared to the biopsy or other diagnostic testing, such as the MRI or PET scan).2

Benefits of Prolaris genomic test

Why might this assessment of cancer aggressiveness be so useful? This is where the issue of overtreatment and undertreatment comes into play. For a young, relatively healthy man the immediate reaction to a prostate cancer diagnosis maybe “get it out.” On the flip side, he may not want to deal with potential years of side effects. If Prolaris can give an assessment of aggressiveness, the decision-making process, both on the side of the medical team making recommendations and for the patient, may become much easier. One can imagine this same process playing out for an elderly or otherwise health compromised patient. It may be easier to take an active surveillance stance if a genomic test points towards less aggressive cancer.

It should be noted that the Prolaris test can also be done on tissue from a radical prostatectomy. It can give a risk assessment of 10-year biochemical recurrence. One can easily see how this could be used to assist with monitoring and making treatment decisions based on changing circumstances.3

Reviewing the research

Studies that have been done on the Prolaris test have generally focused on how its use has translated into changes in clinical decisions. Overall the results have tended to lean towards a higher percentage of the changes being in the direction of reduced therapy recommendations. For example, Crawford et al found a 37.2% reduction in those recommended for interventional treatment. Correspondingly, for those with a pre-Prolaris recommendation of non-intervention (watchful waiting/active surveillance) they found 23.4% of those shifted towards intervention.4 What is missing from the research is an analysis of the long-term impact on clinical outcomes and assessments of cost-benefit.

Addressing research gaps

An example of the missing aspects of the research impacting the use of the test in the here and now is a review of clinical and economic evidence of the Prolaris test conducted by a Canadian province in 2017 (basically a cost-benefit analysis). They determined that “there is insufficient data to inform the cost-effectiveness of the CCP test,” thus the cost would be too much for public funding.5 In layman’s terms — not enough research. They searched 3,021 citations from June 2010 to July 2016 and found only two before and after studies that met their inclusion criteria. Both of these studies found pretty large changes in treatment decisions based on Prolaris — one found 64.9% change from initial to final plan and the other in nearly half the cases. However, in both cases, the authors rated the quality of the evidence as very low. On cost-effectiveness, the authors looked at 100 citations and found no studies that met the inclusion criteria.

Leaving aside the fact that they basically threw aside two studies that verified the impact of the test on treatment decisions due to a lack of clinical outcome information for patients (note: that information may simply have been unavailable yet or survival rates could be equally high due to the initial diagnosis being low grade, low volume), this study absolutely illustrates the overall lack of research on the long-term impact of the Prolaris test. This is not the criticism (at least from me) that it may seem.

There simply has not been time to look at the impact on overall treatment outcomes and what treatment changes prompted by Prolaris mean for overall costs. However, it does illustrate that in the absence of research, expense will become the dictator of utilization of a medical test.  What makes this really potentially sad in this case is that it is easy to imagine the Prolaris genomic test directing enough patients toward active surveillance or early treatment for aggressive cancer to make the test highly cost-effective in the long-run — see the Crawford study for example.

Use genetics to make informed treatment decisions

There is actually still research being done to assess the impact of the Prolaris genomic test on front-line treatment decisions. Less than two months ago, on June 27, 2019, the manufacturer announced the results of a new study of 1,062 men with localized prostate cancer. They found that those with a high Prolaris score were up to four times more likely to develop metastatic cancer. Stephen Bardot, one of the study investigators stated: “Importantly, the Prolaris test provided critical information that can be used to determine which men with localized prostate cancer are candidates for active surveillance and which men should receive definitive therapy with surgery or radiation at the time of diagnosis.”6 In addition, the manufacturer has a study listed in the NIH Clinical trial database that has an estimated completion date of January 2024.7

Hopefully, the publication of this continuing research will help bring this genomic test more into the forefront of prostate cancer treatment decision-making process. Men with PCa deserve to have as much information as possible in making these life-altering choices.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The ProstateCancer.net team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

  1. Davis, John W. “An Introduction to a Novel Genomic Test and Its Role In Improving Clinical Decisions: Part I: Prostate Biopsy Genomic Testing.” Prostate Cancer Research Institute, edited from Insights February 2014 v.17 iss. 1. Available at https://pcri.org/prolaris-test-for-low-risk-prostate-cancer. Accessed August 16, 2019.
  2. Ibid.
  3. Davis, John W. “Use of genomic markers to risk stratify men with prostate cancer.” Trends in Urology & Men’s Health. May/June 2015, pp. 36-39. Available at https://trendsinmenshealth.com/wp-content/uploads/sites/13/2015/05/Davis-Genomic-markers.pdf. Accessed August 16, 2019.
  4. Crawford, David E. et al. “Cell cycle progression score and treatment decisions in prostate cancer: results from an ongoing registry.” Current Medical Research and Opinion, v. 30, iss.6, 2014. Available at https://www.tandfonline.com/doi/abs/10.1185/03007995.2014.899208. Accessed August 16, 2019.
  5. Ontario Health Technology Assessment Series. “Prolaris Cell Cycle Progression Test for Localized Prostate Cancer: A Health Technology Assessment.” 2017; 17(6): 1-75. Published online 2017, May 1. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451271/. Accessed August 16, 2019.
  6. “Prolaris Test Accurately Predicts Risk of Metastasis in Men Diagnosed with Localized Prostate Cancer,” Press Release: Myriad Genetics Inc. June 27, 2019. Available at https://www.urotoday.com/recent-abstracts/urologic-oncology/prostate-cancer/113492-prolaris-test-accurately-predicts-risk-of-metastasis-in-men-diagnosed-with-localized-prostate-cancer.html. Accessed August 17, 2019.
  7. NIH National Library of Medicine. “Prospective Prolaris Value and Efficacy (P-Prove)” Available at https://clinicaltrials.gov/ct2/show/NCT03152448. Accessed August 16, 2019.
  8. Protein and Genetic Testing for Prostate Cancer. Medicare Advantage coverage. Available at https://www.bcbswny.com/content/dam/COMMON/non-secure/provider/Protocols/P/prov_prot_Prostate_CA.pdf Accessed August 16, 2019.

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