Principal Source: Harris R, Lohr KN. Screening for prostate cancer: an update of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med 2002; 137(11):917-29.

Discussant: Weber Chen, MD

Dr. Chen is an oncologist and hematologist in Los Angeles, CA.

Medicine in Brief summarizes discoveries, clinical tests, or guidelines published in internal medicine literature that can affect psychiatric patients and practice. This information is intended to help you:

keep current with important developments in internal medicine
knowledgeably discuss these developments with medical colleagues
determine when to refer patients to a primary care physician or specialist
manage psychiatric issues while your patients undergo evaluation or treatment for a medical condition.

All men age >65—including psychiatric patients—are at higher risk for prostate cancer. The prostate-specific antigen (PSA) blood test can detect prostate cancer early and decrease mortality but often returns a false positive. Because this can increase a patient’s anxiety and lead to unnecessary procedures, consider the psychological impact of waiting for PSA test results as well as possible risk factors for prostate cancer (Table 5).¹ Refer patients at high risk or those with elevated PSA levels to primary care physicians for evaluation.

Clinical Point

No randomized studies have confirmed that PSA screening decreases prostate cancer mortality

PSA testing. The PSA blood test is the screening method of choice for detecting prostate cancer. Before the test’s release in 1992, most prostate cancers were identified at an advanced and incurable state. Because early-stage prostate cancer has few signs or symptoms, PSA screening can identify localized and potentially curable disease.

Despite its benefits, PSA screening in prostate cancer is controversial.

Detection of clinically insignificant cancers may lead to unnecessary treatments.
An elevated PSA lacks specificity. Despite an increased likelihood of prostate cancer in men with moderately elevated PSA (4 to 10 ng/ml), biopsy usually reveals benign prostatic hyperplasia (BPH) rather than prostate cancer.
No randomized studies have confirmed that PSA screening decreases prostate cancer mortality. It is not clear that early detection and treatment changes the natural history and outcome of the disease.²

Table 5

Risk factors for prostate cancer

Age	>65
Race	African-American
Genetics	Family history and hereditary prostate cancer (HPC-1) and predisposing for cancer of the prostate (PCP) genes
Diet	High animal fat
Hormone	High serum testosterone levels
Source: Reference 1

PSA originally was introduced as a tumor marker to detect cancer recurrence or disease progression after treatment. However, it became an important cancer screening tool by the early 1990s and led to a spike in the incidence of prostate cancer, peaking in 1992.³ Most of these newly diagnosed cancers were clinically localized or organ confined, which led to an increase in radical prostatectomy and radiation therapy.

Clinical Point

Studies show that PSA elevations precede clinical disease by an average of 5 years

PSA and cancer risk. PSA is a glycoprotein produced by prostate epithelial cells. The upper limit of normal PSA levels is 4 ng/ml. The positive predictive value for prostate cancer at PSA levels between 4 and 10 ng/ml is approximately 25% but increases to 42% to 64% at PSA levels >10 ng/ml.⁴ Nearly 75% of cancers detected within the “gray zone”—PSA values between 4 and 10.0 ng/ml—are organ confined and potentially curable. At PSA values >10 ng/ml less than half of cancers detected are organ-confined.¹

Studies show that PSA elevations precede clinical disease by an average of 5 years.⁵ PSA elevations may occur with other benign conditions particularly BPH and prostatitis. Digital rectal exams (DRE), ejaculation, prostate biopsy, and acute urinary retention also can cause elevated PSA levels.

Should your patient be tested? The American Cancer Society recommends PSA screening and DRE for men age ≥50 who have ≥10 years life expectancy. Men at higher risk, such as African-Americans and those with a family history of prostate cancer, should begin testing between ages 40 and 45.

Prostate cancer is the most frequently diagnosed cancer in men in the United States. Each year more than 200,000 cases are diagnosed, and approximately 25,000 prostate cancer patients die. Prostate cancer is the second leading cause of cancer death in men after lung cancer and is usually diagnosed in men age 6

Practice Points

If your patient has any urinary changes or an abnormal PSA, err on the side of caution and refer to a primary care provider.
Despite the risk of false positives, PSA remains a powerful biomarker and should be used to screen for prostate cancer.
PSA screening can help patients and physicians choose the optimal course if treatment is indicated.

Related resources

National Cancer Institute. Prostate Cancer. www.cancer.gov/cancertopics/types/prostate.
Emedicine.com. Prostate cancer. www.emedicine.com/urology/index.shtml#prostate.
National Comprehensive Cancer Network. www.nccn.org.

Disclosure

Dr. Chen reports no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.

What you need to know about PSA screening for prostate cancer