Criteria for Choosing a Screening Test for Prostate Cancer
The primary criterion for selecting a screening test like PSA is 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—not simply detecting as many cases as possible or being inexpensive and widely available. 1
The Fundamental Goal: Early Detection of Aggressive Disease
The answer to this question is Option B: Detect early cancer stage—but with critical qualifications that distinguish effective screening from harmful overdetection.
Why Early Stage Detection is the Correct Answer
The National Comprehensive Cancer Network explicitly states that the fundamental goal 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
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—this means detecting "as many cases as possible" (Option A) would cause massive harm through overdiagnosis. 1
Early detection only matters when coupled with adequate life expectancy (10-15 years) to benefit from treatment, as this is the timeframe needed for early detection and treatment to impact outcomes. 2, 1
Why the Other Options Are Incorrect
Option A (Detect as Many Cases as Possible) is Wrong
Prioritizing sensitivity alone causes a test to detect every cancer including all indolent disease, leading to massive overdiagnosis and overtreatment with attendant complications including incontinence, impotence, and bowel dysfunction. 1
The 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 screening may increase cancer detection (18 more per 1000 men) but probably has little or no effect on all-cause mortality (0 fewer per 1000) and minimal effect on prostate cancer mortality (1 fewer per 1000) at 10 years—demonstrating that detecting more cancers does not equal better outcomes. 3
Option C (Inexpensive and Widely Available) is Secondary
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 principal strengths of PSA include reasonable cost and high patient acceptance, but these are mentioned alongside its critical weakness: imperfect specificity that leads to false positives, expensive diagnostic evaluation, and unwarranted patient anxiety. 2
Option D (Done for Patients with Symptoms) Contradicts Screening
Screening by definition is performed on asymptomatic individuals—testing symptomatic patients is diagnostic evaluation, not screening. 4
The American College of Physicians recommends using ICD-10 code Z12.5 specifically for asymptomatic men requesting PSA screening. 4
The Critical Balance: Specificity Matters as Much as Early Detection
Avoiding the Overdetection Trap
A screening test must have adequate specificity to avoid false-positives—PSA testing has poor specificity of only 60-70% at the conventional 4.0 ng/mL cutoff. 1
Two-thirds of men with elevated PSA have negative biopsies (false positives), with biopsy complications including blood in semen (93%), blood in urine (66%), pain (44%), fever (18%), and hospitalization for sepsis (1-2%). 3
Biomarker tests and multiparametric MRI can improve specificity and reduce unnecessary biopsies by 20-30%. 1
Risk Stratification is Essential
The test should enable risk stratification—men with PSA <1.0 ng/mL at age 60 have <0.3% likelihood of prostate cancer death, allowing less intense follow-up. 1
Men must have at least 10-15 year life expectancy to potentially benefit from screening, and screening men with limited life expectancy substantially increases overdetection without mortality benefit. 1, 3
Common Pitfalls to Avoid
Never Screen Without Counseling
Screening without counseling represents inappropriate use—two-thirds of US men reported no discussion with physicians about advantages, disadvantages, or scientific uncertainty regarding PSA screening. 1, 3
The European Association of Urology explicitly recommends against PSA testing without prior counseling on potential risks and benefits. 2, 3
Don't Screen Men with Limited Life Expectancy
Screening men over 75 years or those with <10 year life expectancy substantially increases overdetection without mortality benefit. 1
Very few men above age 75 benefit from PSA testing, and adequate evidence shows that harms of screening in men older than 70 years are at least moderate and greater than in younger men. 1