What complete blood count (CBC) tests indicate the presence of prostate cancer?

From the Guidelines

A Complete Blood Count (CBC) test alone cannot diagnose prostate cancer, and specific tests such as Prostate-Specific Antigen (PSA) blood test are required for diagnosis. While CBC may show general health indicators like anemia or infection, prostate cancer requires additional tests for definitive diagnosis. An elevated PSA level (typically above 4 ng/mL, though this varies by age) may indicate prostate cancer, but can also be elevated due to benign conditions like prostatitis or benign prostatic hyperplasia 1. For definitive diagnosis, additional tests are necessary, including digital rectal examination, prostate biopsy, and imaging studies like MRI. CBC results might show secondary effects of advanced prostate cancer, such as anemia if the cancer has spread to bone marrow, but these findings are non-specific 1.

Diagnostic Tools

The different available diagnostic tools can be used separately, or in multiple-tier combinations, to indicate the need for a prostate biopsy. An abnormal DRE is an indication for biopsy, but as an independent variable, PSA is a better predictor of cancer than either DRE or transrectal ultrasound (TRUS) 1.

• PSA is a continuous parameter, with higher levels indicating a greater likelihood of PCa, precluding an optimal PSA threshold for detecting nonpalpable but clinically significant PCa.
• Risk calculators developed from cohort studies may also be useful in reducing further testing.
• Prostate-specific antigen density (PSA-D; serum PSA divided by prostate volume) may also help predict the presence of csPCa especially in smaller prostates using a cut-off of 0.15 ng/ml/cc.
• Multiparametric magnetic resonance imaging (mpMRI) is increasingly important for biopsy optimisation.

Recommendation

If prostate cancer is suspected, consult a urologist who will recommend appropriate diagnostic tests beyond a standard CBC. A limited PSA elevation alone should be confirmed after a few weeks under standardised conditions (ie, no ejaculation, manipulations, or urinary tract infections) in the same laboratory before considering further testing 1.

From the Research

CBC Blood Tests for Prostate Cancer

The presence of prostate cancer can be indicated by certain blood tests, including:

• Prostate-Specific Antigen (PSA) test: This test measures the level of PSA in the blood, which can be elevated in men with prostate cancer 2, 3, 4.
• Digital Rectal Examination (DRE): While not a blood test, DRE is often used in conjunction with PSA testing to detect prostate cancer 2, 5, 3, 4.

Role of PSA in Prostate Cancer Detection

PSA testing is a common method for detecting prostate cancer, and its effectiveness has been studied in various trials:

• The PSA level is as effective as or more effective than DRE for the detection of prostate cancer 2.
• The combined use of DRE and PSA testing provides a more complete evaluation of the prostate gland for malignant involvement 2.
• PSA measurements are often used in conjunction with other tests, such as MRI, to detect prostate cancer 5.

Other Blood Tests

While PSA is the most commonly used blood test for prostate cancer detection, other tests may also be used:

• None of the provided studies mention specific CBC blood tests that can detect prostate cancer, aside from PSA 6, 2, 5, 3, 4.

Limitations and Controversies

The use of blood tests for prostate cancer detection is not without controversy:

• The evidence for and against prostate cancer screening remains highly controversial 3.
• Different medical organizations have varying recommendations for prostate cancer screening, and there is no standard of care 3.