PSA Diagnostic's Usage Path

A study released in November detailed why prostatectomy is not the ideal treatment response to a man’s elevated prostate-specific antigen (PSA) level. Study authors followed disease progression in men who had received a prostatectomy. The result: half of the 253 individuals developed metastasis. At 10 years, metastasis-free survival was 37%.¹

A non-invasive lab test is widely available to help a patient and physician decide, with more quantitative knowledge, whether a prostate biopsy is necessary in response to an elevated PSA level. Called the 4Kscore test, the assay is based on biomarkers from four kallikrein proteases specific to the prostate, as well as information specific to the patient, like his age. The test provides a numerical value that relates to the presence of aggressive prostate cancer.²

The test, made by Miami-based Opko Health, has been in use since 2014, but only as a laboratory developed test (LDT), an FDA designation that confines a product’s use to one laboratory. The FDA gave its marketing approval in December. The FDA, according to its website, approved the product for use in men in various age groups with specific PSA levels and/or an abnormal digital rectal examination. For example, the test is approved from men 45 to 54 years old whose total PSA is less than 2 ng/mL and/or with an abnormal digital exam result. Also included in the calculation is a prior biopsy. Aggressive prostate cancer is a Gleason score greater than or equal to 7; the Gleason grade group is greater than or equal to 2.

The algorithm used in the 4Kscore was developed at Memorial Sloan Kettering. According to the product press release, researchers there used more than 30,000 cryopreserved blood samples. The FDA based its approval decision on two studies, one³ of which included 1,476 men who took the 4Kscore test before radical prostatectomy. The test improved prediction of biochemical recurrence in all patients, according to study results.

Christine Bahls is a freelance writer for medical, clinical trials, and pharma information.

References

1. Perera M, Lebdai S, Tin AL, et al. Oncologic outcomes of patients with lymph node invasion at prostatectomy and post-prostatectomy biochemical persistence. Urol Oncol. 2022 Nov 23:S1078-1439(22)00403-3.
2. Opko Health press release. OPKO Health Receives U.S. FDA Approval for the 4Kscore®
3. Rasmussen M, Fredsøe J, Tin AL, et al. Independent validation of a pre-specified four-kallikrein marker model for prediction of adverse pathology and biochemical recurrence. Br J Cancer. 2022 Apr;126(7):1004-1009. doi: Accurate markers for prostate cancer (PC) risk stratification could aid decision-making for initial management strategies. The 4Kscore has an undefined role in predicting outcomes after radical prostatectomy (RP).