Summary of Evidence
Note: Separate PDQ summaries on Prostate Cancer Prevention, Prostate Cancer Treatment, and Levels of Evidence for Cancer Screening and Prevention Studies are also available.
Digital Rectal Examination and Prostate-Specific Antigen
The evidence is insufficient to determine whether screening for prostate cancer with prostate-specific antigen (PSA) or digital rectal exam (DRE) reduces mortality from prostate cancer. Screening tests are able to detect prostate cancer at an early stage, but it is not clear whether this earlier detection and consequent earlier treatment leads to any change in the natural history and outcome of the disease. Observational evidence shows a trend toward lower mortality for prostate cancer in some countries, but the relationship between these trends and intensity of screening is not clear, and associations with screening patterns are inconsistent. The observed trends may be due to screening, or to other factors such as improved treatment. Results from two randomized trials show no effect on mortality through 7 years but are inconsistent beyond 7 to 10 years.
Description of the Evidence
- Study Design: Evidence obtained from observational and descriptive studies (e.g., international patterns studies, time series).
- Internal Validity: Fair.
- Consistency: Poor.
- Magnitude of Effects on Health Outcomes: Uncertain.
- External Validity: Poor.
Based on solid evidence, screening with PSA and/or DRE detects some prostate cancers that would never have caused important clinical problems. Thus, screening leads to some degree of overtreatment. Based on solid evidence, current prostate cancer treatments, including radical prostatectomy and radiation therapy, result in permanent side effects in many men. The most common of these side effects are erectile dysfunction and urinary incontinence.[1-3] Whatever the screening modality, the screening process itself can lead to adverse psychological effects in men who have a prostate biopsy but do not have identified prostate cancer. Prostatic biopsies are associated with complications, including fever, pain, hematospermia/hematuria, positive urine cultures, and rarely sepsis.
Description of the Evidence
- Study Design: Evidence obtained from cohort or case-control studies.
- Internal Validity: Good.
- Consistency: Good.
- Magnitude of Effects on Health Outcomes: 20% to 70% of men who had no problems before radical prostatectomy or external-beam radiation therapy will have reduced sexual function and/or urinary problems.
- External Validity: Good.
- Harris R, Lohr KN: Screening for prostate cancer: an update of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med 137 (11): 917-29, 2002. [PUBMED Abstract]
- Litwin MS, Pasta DJ, Yu J, et al.: Urinary function and bother after radical prostatectomy or radiation for prostate cancer: a longitudinal, multivariate quality of life analysis from the Cancer of the Prostate Strategic Urologic Research Endeavor. J Urol 164 (6): 1973-7, 2000. [PUBMED Abstract]
- Steineck G, Helgesen F, Adolfsson J, et al.: Quality of life after radical prostatectomy or watchful waiting. N Engl J Med 347 (11): 790-6, 2002. [PUBMED Abstract]
- Fowler FJ Jr, Barry MJ, Walker-Corkery B, et al.: The impact of a suspicious prostate biopsy on patients' psychological, socio-behavioral, and medical care outcomes. J Gen Intern Med 21 (7): 715-21, 2006. [PUBMED Abstract]
- Rietbergen JB, Kruger AE, Kranse R, et al.: Complications of transrectal ultrasound-guided systematic sextant biopsies of the prostate: evaluation of complication rates and risk factors within a population-based screening program. Urology 49 (6): 875-80, 1997. [PUBMED Abstract]