What blood results indicate the presence of prostate cancer, specifically elevated Prostate-Specific Antigen (PSA) levels?

From the Guidelines

The primary blood test used to detect the presence of prostate cancer is the Prostate-Specific Antigen (PSA) test, with a level above 4.0 ng/mL considered elevated and potentially indicative of prostate cancer, as supported by the NCCN guidelines 1. The PSA test is not definitive, as elevated levels can also be caused by benign conditions such as prostate inflammation or enlargement. Additional blood markers that may be used to assess the risk of prostate cancer include:

• free PSA percentage, where a lower percentage of free PSA relative to total PSA suggests a higher cancer risk
• PSA velocity, where rapid increases over time are concerning
• PSA density, which is the PSA level relative to prostate size
• Newer blood tests like the Prostate Health Index (phi) and 4Kscore, which combine multiple markers to improve accuracy, as discussed in the guidelines 1. It's essential to understand that blood tests alone cannot definitively diagnose prostate cancer; they only indicate the need for further evaluation. Abnormal blood results typically lead to additional testing, such as prostate biopsy, which is the only way to confirm a cancer diagnosis. Regular PSA screening is recommended for men starting at age 50, or earlier for those with risk factors like family history or African ancestry, as stated in the guidelines 1. The level of PSA correlates with the risk of prostate cancer, with total PSA levels >10 ng/mL conferring a greater than 67% likelihood of prostate cancer, as demonstrated by the Prostate Cancer Prevention Trial (PCPT) 1. A PHI >35, percent free PSA <10%, and/or PCA3 score >35 are strongly suspicious for prostate cancer, as indicated in the guidelines 1. In summary, a PSA level above 4.0 ng/mL, combined with other markers and risk factors, can indicate the presence of prostate cancer, and further evaluation with biopsy is necessary for a definitive diagnosis, as emphasized by the NCCN guidelines 1.

From the Research

Blood Results for Prostate Cancer

The presence of prostate cancer can be indicated by several blood results, including:

• Prostate Specific Antigen (PSA) levels 2, 3, 4, 5
• Human Kallikrein-2 (hK2) levels 2, 4
• Free Prostate Specific Antigen (fPSA) levels 2, 3, 4
• The ratio of fPSA to PSA [%fPSA] 3, 4
• The ratio of hK2 to fPSA [hK2/fPSA] 2, 4

Biomarkers for Prostate Cancer

Several biomarkers have been studied for their potential to detect prostate cancer, including:

• PSA 2, 3, 4, 5
• hK2 2, 4
• fPSA 2, 3, 4
• PCA3 (prostate cancer antigen 3) 3
• A kallikrein panel (4k-panel) 3

Studies on Prostate Cancer Biomarkers

Several studies have investigated the use of these biomarkers for detecting prostate cancer, including:

• A study published in 2015 found that the ratio of hK2 to fPSA was significantly higher in prostate cancer patients than in patients with benign prostate hyperplasia (BPH) 2
• A study published in 2014 found that the addition of %fPSA, PCA3, and a kallikrein panel to the European Randomised Study of Screening for Prostate Cancer (ERSPC) risk calculator improved the detection of prostate cancer in prescreened men 3
• A study published in 2004 found that the use of multiple biomarkers, including hK2, PSA, and fPSA, improved the detection of prostate cancer in African-American men 4
• A study published in 2024 found that repeat PSA testing improved risk stratification for men undergoing magnetic resonance imaging (MRI) and targeted biopsy for suspected prostate cancer 5