DIfferent effects of screening on prostate cancer death in two trials
Menée à partir de l'analyse des données d'un essai européen (environ 184 000 hommes âgés de 55 à 69 ans) et d'un essai américain (environ 155 000 hommes âgés de 55 à 74 ans) dont les résultats observés sont contradictoires, cette étude évalue les effets d'un dépistage du cancer de la prostate par test du PSA sur la mortalité spécifique relative
What is the problem and what is known about it so far?
Prostate cancer occurs frequently, and the screening test does a good job of identifying men with the disease. Some cancer cases respond well to treatment, but others do not need treatment because the cancer does not respond or because it grows very slowly. It is difficult to separate cancer that responds from other cancer, so it is difficult to know when to treat and when not to treat. In this situation, screening involves tradeoffs. If screening is not done, more men will fail to get treatment that might prevent premature death because their cancer will go undetected until after it has spread. If screening is done, more men will get treatment that cannot help them, and some of them will have lower quality of life due to the treatment.
Why did the researchers do this particular study?
Two clinical trials—one in Europe and the other in the United States—provide the best information about whether screening lowers the risk for death due to prostate cancer. The European study found that men who were invited to be screened had fewer prostate cancer deaths than men who were not invited, but the American study found similar numbers of prostate cancer deaths in the 2 groups. The researchers of the current study wanted to figure out whether the results of the 2 trials were as different as they seemed.
Annals of Internal Medicine , article en libre accès, 2016