Criteria for Choosing a Prostate Cancer Screening Test
The primary criterion for selecting a prostate cancer screening test should be its ability to detect clinically significant, high-grade cancers early enough to enable curative treatment, while minimizing detection of indolent disease that would never threaten the patient's life. 1
The Fundamental Goal: Early Detection of Aggressive Disease
The core objective of prostate cancer screening is to identify aggressive prostate cancer early and cure it before it spreads outside the prostate, while avoiding overdetection of indolent tumors. 1 This represents a critical balance because autopsy studies demonstrate that prostate cancer may be present in 33% of men over age 50, yet most of these cancers would never become clinically apparent during the patient's lifetime. 1
Why "Detecting as Many Cases as Possible" is Wrong
Prioritizing sensitivity alone (detecting every cancer) causes massive overdiagnosis and overtreatment, with attendant complications including incontinence, impotence, and bowel dysfunction. 1 The evidence clearly shows that PSA screening can detect early-stage prostate cancer, but this detection capability has led to substantial harms including frequent false-positive results, unnecessary anxiety, biopsies, and potential complications of treatment of cases that may never have affected a patient's health. 2
Approximately 2 in 3 men who undergo radical prostatectomy will experience long-term erectile dysfunction, and 1 in 5 men develop long-term urinary incontinence. 3 These are not trivial harms when applied to men whose cancers would never have threatened their lives.
The Critical Importance of Specificity Over Sensitivity
A screening test must have adequate specificity to avoid false-positives that lead to unnecessary biopsies, patient anxiety, and potential complications, including drug-resistant infections. 1 PSA testing has poor specificity and often produces false-positive results at the conventional 4.0 ng/mL cutoff, with specificity of only 60-70%. 2
The European Randomized Study of Screening for Prostate Cancer demonstrated a 20% relative reduction in prostate cancer deaths among those screened at 9 years, but this benefit came at the cost of substantial overdetection and overtreatment. 2 Biomarker tests and multiparametric MRI can improve specificity and reduce unnecessary biopsies by 20-30%. 1
Early Stage Detection Must Link to Treatment Benefit
Men must have at least a 10-15 year life expectancy to potentially benefit from screening, as this is the timeframe needed for early detection and treatment to impact outcomes. 1 Screening men over 75 years or those with less than 10 year life expectancy substantially increases overdetection without mortality benefit. 1
The USPSTF found that PSA-based screening programs in men aged 55 to 69 years may prevent approximately 1.3 deaths from prostate cancer over approximately 13 years per 1000 men screened, and may prevent approximately 3 cases of metastatic prostate cancer per 1000 men screened. 3 However, the potential benefits of PSA-based screening in men 70 years and older do not outweigh the expected harms. 3
Cost and Availability are Secondary Considerations
While cost-effectiveness and wide availability are relevant factors, these are secondary to the test's ability to improve clinical outcomes without causing net harm. 1 The test must enable risk stratification—for example, men with PSA less than 1.0 ng/mL at age 60 have less than 0.3% likelihood of prostate cancer death, allowing less intense follow-up. 1
The Shared Decision-Making Imperative
The test must be acceptable enough to allow shared decision-making and informed consent, as screening should never occur without patients understanding the benefits, risks, and uncertainties. 1 Two-thirds of US men reported no discussion with physicians about advantages, disadvantages, or scientific uncertainty regarding PSA screening—this represents inappropriate use. 1
Clinicians should not order the PSA test without first discussing with the patient the potential but uncertain benefits and the possible harms of prostate cancer screening. 2 Men should be informed of the gaps in the evidence and assisted in considering their personal preferences and risk profile before deciding whether to be tested. 2
Common Pitfalls in Test Selection
Do not screen without counseling about the balance of benefits and harms. 1 The decision to undergo periodic PSA-based screening for men aged 55 to 69 years should be an individual one and should include discussion of the potential benefits and harms with their clinician. 3
Do not screen men with limited life expectancy. 1 Very few men above the age of 75 years benefit from PSA testing. 2 Adequate evidence shows that the harms of screening in men older than 70 years are at least moderate and greater than in younger men because of increased risk of false-positive results, diagnostic harms from biopsies, and harms from treatment. 3