The PSA test and prostate cancer screening

Prostate-specific antigen is a protein made by normal and cancerous cells of the prostate gland. In 1986 the US Food and Drug Administration approved a PSA blood test for monitoring men already diagnosed with prostate cancer. The next year Thomas Stamey and colleagues reported on 2,200 serum samples from 699 patients. PSA was raised in 122 of 127 men with newly diagnosed, untreated prostate cancer, rose with stage and tumor volume, and fell to undetectable levels after radical prostatectomy. It was also raised in 86 percent of men with benign prostatic enlargement, so it was not specific for cancer.

In 1991 William Catalona and colleagues measured PSA in 1,653 healthy men aged 50 or older. Of 85 biopsied men with levels of 4.0 to 9.9 micrograms per liter, 19 had cancer; of 27 biopsied men with levels of 10 or higher, 18 did. In 1994 the FDA approved the PSA test, used with a digital rectal examination, to help detect prostate cancer in men without symptoms.

Two large randomized trials reported in March 2009. In the American PLCO trial, 76,693 men were assigned to annual screening or usual care; after 7 to 10 years, deaths from prostate cancer did not differ significantly between the groups. In the European ERSPC trial of 162,243 men aged 55 to 69, screening cut the prostate cancer death rate by 20 percent after a median of 9 years, but 1,410 men had to be screened and 48 extra cancers treated to prevent one death.

The harms were concrete. About 6 to 7 percent of men have a false-positive PSA test in any round of screening, biopsies can cause serious infection, pain and bleeding, and some cancers found would never have caused symptoms. In 2012 the US Preventive Services Task Force recommended against PSA screening for men of any age. In 2018 it changed course: men aged 55 to 69 should decide individually with their clinicians, and men 70 and older should not be screened. It estimated that screening 1,000 men aged 55 to 69 for 13 years would avoid about 1.3 prostate cancer deaths.