To evaluate whether effects of screening on prostate cancer mortality relative to no screening differed between the ERSPC and PLCO.
After re-analyzing the data from both trials, Etzioni says the USA and European results were similar; both studies showed benefits.
The risk of developing prostate cancer increases with age and the condition usually develops in men aged 50 years or older.
The findings of the new study appeared in the most recent edition of the Annals of Internal Medicine.
The study concluded that "two important prostate cancer screening trials provide compatible evidence that screening reduces prostate cancer mortality".
The unclear results - and the risk that the blood tests could lead to unnecessary biopsies and treatments - led the government-backed U.S. Preventive Services Task Force (USPSTF) to recommend against PSA screening.
In the USA, that led to a surge in what some doctors view as unnecessary medical treatments that put men at risk without providing them much benefit.
However, the authors of the latest analysis note that the USA recommendation relies heavily on results from the ERSPC (European Randomized Study of Screening for Prostate Cancer) and the PLCO (Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial), which offer conflicting results.
"Screening was estimated to confer a 7% to 9% reduction in the risk for prostate cancer death per year of mean lead times", they write. Given the uncertainty, and the risks of treating cancers that weren't aggressive, the USPSTF decided there wasn't convincing enough evidence to recommend PSA screening. About 1 man in 39 will die of prostate cancer.
Another difference was that in the US trial, doctors set a higher threshold of PSA levels for obtaining a biopsy, which could mean that men in the European trial were treated slightly sooner. They gathered data from all the randomized controlled trials in Europe and the United States including men aged 55 to 69 (in case of ERSPC population) or 55 to 74 (in case of PLCO population) years. It found that the US study actually agreed with the results of the European study showing that prostate cancer screening does save lives.
The current results should give more men and their doctors confidence that PSA testing can detect cancers, and that doing so could prolong their lives.
Mertens also told 22News that prostate cancer is the second leading cause of cancer death in men, the first being lung cancer. Men diagnosed with prostate cancer are now living longer than ever before and research efforts seem to be producing results, the president said.
The author of an accompanying editorial from Sloan Kettering Cancer Center hopes that this paper will put to rest the question of whether PSA screening reduces prostate cancer mortality.