What is the role and limitation of PSA testing in prostate cancer screening?

• A. PSA helps detect possible cancer but is not diagnostic; elevated PSA warrants DRE and biopsy; false positives/overdiagnosis risk.
• B. PSA confirms cancer diagnosis without biopsy
• C. PSA is diagnostic when elevated
• D. PSA has no limitations and is definitive

Answer: (A)

PSA testing serves as a screening tool to flag possible prostate issues, not to diagnose cancer. An elevated PSA heightens suspicion for cancer, but confirmation requires a biopsy that shows cancer cells and provides a Gleason grade. In practice, a digital rectal exam and sometimes MRI or other risk-stratifying tests help determine whether a biopsy is warranted after a PSA result. PSA can rise for many noncancer reasons—benign prostatic hyperplasia, prostatitis, recent ejaculation, infection, or recent procedures—so a higher PSA does not prove cancer. This leads to false positives and, because many detected cancers are slow-growing, potential overdiagnosis and overtreatment. While tools like age-adjusted thresholds, PSA density, and free-to-total PSA ratios can refine risk, they do not replace biopsy when cancer is suspected. Thus PSA is useful for detecting possible cancer and guiding further evaluation, but it is not diagnostic and has notable limitations.