No AccessJournal of UrologyAdult Urology1 Aug 2020

Prespecified 4-Kallikrein Marker Model at Age 50 or 60 for Early Detection of Lethal Prostate Cancer in a Large Population Based Cohort of Asymptomatic Men Followed for 20 Years

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A prespecified statistical model based on 4 kallikrein markers in blood, commercially available as the 4Kscore®, has been shown to accurately detect high grade (greater than Grade Group 2) prostate cancer in men with moderately elevated prostate specific antigen. We assessed whether the model predicted prostate cancer metastasis or death in men not subject to prostate specific antigen screening.

Materials and Methods:

The cohort includes 43,692 unscreened prostate cancer-free men from a Swedish population based cohort with low rates of prostate specific antigen screening (Västerbotten Intervention Project). Using cryopreserved blood collected at ages 50 and 60 years from men in this cohort we analyzed the association between prostate specific antigen and other kallikrein marker levels in blood and risk of prostate cancer metastasis or death.


There were 308 with metastases and 172 prostate cancer deaths. Baseline prostate specific antigen was strongly associated with 20-year risk of prostate cancer death (c-index at age 50, 0.859, 95% CI 0.799–0.916; age 60, 0.840, 95% CI 0.799–0.878). Men 60 years old with prostate specific antigen below median (less than 1.2 ng/ml) had 0.4% risk of prostate cancer death at 20 years. Among men with moderately elevated prostate specific antigen (2.0 ng/ml or greater) the 4Kscore markedly improved discrimination (c-index 0.767 vs 0.828 and 0.774 vs 0.862 in men age 50 and 60, respectively). Long-term risk of prostate cancer death or metastasis in men with low 4Kscores was very low.


Screening should focus on men in top prostate specific antigen quartile at age 60 years. Men with elevated prostate specific antigen but a low 4Kscore can safely be monitored with repeated blood markers in place of immediate biopsy.


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Presented at annual meeting of American Urological Association, San Francisco, California, May 18-21, 2018.

Supported by the National Institutes of Health/National Cancer Institute (NIH/NCI) with a Cancer Center Support Grant to Memorial Sloan Kettering Cancer Center (P30 CA008748), a SPORE grant in Prostate Cancer to Dr. H. Scher (P50-CA92629), an R01 grant to Dr. R. Klein (R01 CA175491), the Sidney Kimmel Center for Prostate and Urologic Cancers, David H. Koch through the Prostate Cancer Foundation. Also supported in part by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre Program in the U.K., the Västerbotten County Council, the Swedish Cancer Society (CAN 2017/559), the Swedish Research Council (VR-MH project no. 2016-02974) and General Hospital in Malmö Foundation for Combating Cancer.

A full data set along with the statistical code used for analysis are available from the authors on request. These data can be used only for replication of the analyses published in this paper. Express written permission must be sought from the authors for any other data use.

No direct or indirect commercial, personal, academic, political, religious or ethical incentive is associated with publishing this article.

Supplementary materials are available at