Prostate Cancer Screening: The Basics

SUMMARY:

Prostate cancer is one of the most common types of cancer that affects patients. In the United States, lifetime risk of prostate cancer is approximately 11%, and the lifetime risk of dying of prostate cancer is 2.5%. Many patients will die with prostate cancer but not necessarily of prostate cancer. In autopsy studies, 20% of patients aged 50 to 59 years old and more than 33% of patients aged 70 to 79 years old were found to have prostate cancer. The overall median age of death from prostate cancer is 80, with more than two-thirds of all patients who die of prostate cancer being older than 75 years old. Measuring the amount of prostate specific antigen (PSA) can be a helpful tool in diagnosing prostate cancer. While population-wide screening is not currently recommended, there is a role for shared decision making for certain groups.

Goals, Benefits and Harms of Prostate Screening

Goal of Prostate Cancer Screening

To prevent morbidity and mortality associated with advanced or metastatic disease by identifying high-risk, localized prostate cancer and reducing prostate cancer mortality
Positive PSA screening test can by followed by a diagnostic transrectal, ultrasound guided, core-needle prostate biopsy that can guide treatment recommendations

Benefits of Early Detection and Treatment

RCTs demonstrate that PSA-based prostate cancer screening in patients with a prostate aged 55 to 69 years may prevent approximately 1.3 deaths from prostate cancer over 13 years per 1000 individuals screened
Screening may also prevent approximately 3 cases of metastatic disease
There has been a 75% reduction in presentation with metastatic disease since PSA screening for prostate cancer
- However, current data shows no reduction in all-cause mortality with screening

Harms Associated with Screening

Psychological Harm: Overdiagnosis
- Some patients are being treated for a cancer that would otherwise never have become symptomatic during the patient’s lifetime
- Exact rate of overdiagnosis is unknown but estimated to be as high as 50%
Complications of prostate biopsy resulting from a positive screen result
- Procedure is painful | Hematospermia | Prostatitis
- Risk of infection: 4% risk of infection-related hospitalization

Who to Screen? AAFP and USPSTF Recommendations

Screening
- Addresses early, pre-symptomatic screening for asymptomatic prostate cancer
- Is not intended for individuals with symptoms that could be related to either locally advanced or metastatic prostate cancer
- Is based on PSA levels
Data is insufficient to recommend the following
- Digital rectal exam (DRE): DRE does not improve detection of prostate cancer and should not be performed as part of screening
- PSA derivatives and isoforms: e.g., free PSA, -2proPSA, prostate health index, hK2, PSA velocity or PSA doubling time
- Novel urinary markers and biomarkers: e.g., PCA3

Individuals Aged 55 Through 69

Population-wide PSA based screening for prostate cancer is not recommended
55 through 69 years: Use shared decision making
- Benefits: PSA screening may reduce mortality from prostate cancer in a small number of individuals
- Harms: The cost of screening may place many individuals at risk for long term harms as described above | Current trials have demonstrated no reduction in all-cause mortality from prostate cancer screening at the population level
- If the individual desires to undergo screening with PSA testing, do not be screen more frequently than every 2 years
- A common PSA threshold level of 4.0 ng/mL is used to direct further workup and intervention, however thresholds vary by lab and professional society

For Individuals Aged 70 and Older

Recommendation against screening
- Individuals in this age group are more likely to die from a cause other than their prostate cancer
- Patients typically experience more harms than benefits from screening: False positives | Overdiagnosis | Increased risk from biopsy and treatment

High Risk Populations

There is insufficient evidence to determine whether individuals at increased risk for prostate cancer are more likely to benefit from screening
Individuals with increased risk of prostate cancer include
- African American
- Family history of prostate cancer
  - African American individuals with a first degree relative have 3 times the average risk
  - White individuals with a first degree relative have double the average risk

KEY POINTS:

General, population-wide screening for prostate cancer using PSA is not recommended
Starting at age 55 through 69, a discussion with the patient can allow for an informed, shared decision to proceed with screening if desired
- Screening should consist of a PSA test, with a testing interval of no more than 2 years
- In general, If PSA levels are >4.0ng/mL, further workup including imaging, biopsy, and referral to urologist should be considered
Screening for prostate cancer with PSA in individuals aged ≥70 years is not recommended
No recommendation exists for high-risk populations
The decision on screening should be individualized between the clinician and patient