PSA Testing Linked to Improved Prostate Cancer Survival
THURSDAY Aug. 23, 2012 -- Prostate cancer survival rates in the United States have improved since the introduction of prostate-specific antigen (PSA) testing, researchers report.
PSA is a protein released into the body by the prostate gland. PSA screening involves measuring the amount of PSA in a man's blood. The higher the PSA level, the more likely it is that a man has prostate cancer.
The new study, published Aug. 23 in The Journal of Urology, found that routine use of PSA testing for prostate cancer screening and monitoring has resulted in earlier and more sensitive detection of the disease. This has led to improved survival for patients with newly diagnosed prostate cancer that has spread to the bones or other parts of the body ("metastatic prostate cancer").
In addition, the survival rate for black patients has improved and is now about the same as for whites, the investigators found.
For the study, researchers analyzed data from three clinical trials conducted over the last three decades that evaluated patient survival after androgen (hormone)-deprivation treatment for prostate cancer. Two of the clinical trials were conducted before the introduction of PSA screening, and one took place after.
Median survival was 30 months in the first trial (conducted from 1985 to 1986), 33 months in the second trial (conducted from 1989 to 1994), and 49 months in the third trial (conducted from 1995 to 2009). Patients in the most recent trial also had a 30 percent decreased risk of death, the study found.
Among black patients, median survival was 27 months in the first trial and 48 months in the third trial, which is close to that of white patients, the study authors noted in a journal news release.
This improvement in black patients' survival may be due to greater awareness of prostate cancer and increased likelihood that they will seek health care, suggested lead investigator Dr. Ian Thompson, director of the Cancer Therapy and Research Center, a U.S. National Cancer Institute-designated cancer center, and a professor in the urology department at the University of Texas Health Science Center at San Antonio.
However, Thompson noted that black men have a twofold to threefold greater incidence of newly diagnosed metastatic prostate cancer than white men, which contributes to a similarly higher death rate. This shows the need for a greater effort to eliminate disparities in prostate cancer, he pointed out in the news release.
While not all of the improvements in prostate cancer survival "can be attributed strictly to PSA testing, without a doubt it has played a role in extending many lives," Thompson concluded.
PSA testing has been controversial.
In May, the U.S. Preventive Services Task Force recommended against routine PSA screening, saying too many non-dangerous cancers were being treated aggressively and resulting in unnecessary harm.
But a July study in the journal Cancer found that not screening American men would triple the number developing advanced cancer, and the American Society of Clinical Oncology recommended that men with a life expectancy of more than 10 years talk with their doctors about getting the test.
While the new study uncovered an association between routine PSA testing and improved rates of prostate cancer survival, it did not prove a cause-and-effect relationship.
The U.S. National Cancer Institute has more about PSA testing.
Posted: August 2012
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