According to data published today in Lancet Oncology, a 14-year-long Swedish study has unequivocally demonstrated that PSA screening in men of 50 to 65 years of age does reduce the risk of prostate cancer-specific mortality — by about 50 percent. [Editorial comment: Interested readers may also wish to read a further and more detailed commentary on this study posted after we had been able to read a full copy of the study by Hugosson et al.]
There are already multiple reports about this study on various web sites, including Reuters, Bloomberg News, MedPage Today, and HealthDay. The original article by Hugosson et al. was published on line today, along with an editorial commentary by Neal.
As far as we can tell from the media reports, a group of researchers at the University of Gothenburg have been conducted a trial involving 20,000 men aged between 50 and 65 years who were randomized to either receive prostate screening based on PSA testing (once every 2 years) or not. The basic result of the study is that — after 14 years of follow-up — the prostate cancer-specific mortality rate among men in the screening group was about half that of the mortality rate among men in the unscreened group, as men were diagnosed and treated in time to stop the cancer from killing them.
Jonas Hugosson, who led the study, is quoted as stating that the results show that PSA screening of all men in this age group “can result in a relevant reduction in cancer mortality.”
He is also quoted as saying that, “Our study has a longer follow-up than previous studies, but shows that in those men invited [to the study], the risk of dying is only half of that in the control group. In men younger than 60 at study entry, the effect was even more pronounced — only one-quarter of expected deaths occurred.”
The research team reports that — in this study — the risk of over-diagnosis was also less than previously thought, with just 12 men needing to be diagnosed to save one life. However, since the benefit of PSA screening requires at least 10 years to be borne out, they question the value of PSA testing for men over 70 years of age.
Additional information about this study (as reported by the media) includes the following:
- Men in the screening arm whose PSA levels were elevated were offered more tests, including a digital rectal exam and prostate biopsies.
- 44 of the men who had PSA testing died from prostate cancer, compared to 78 men who had not had been screened.
- 11.4 percent of screened men were diagnosed with prostate cancer, compared with 7.2 percent of unscreened men.
- Of the men in the screened group diagnosed with prostate cancer, nearly 79 percent were diagnosed because they took part in the study.
- Men in the screened group were more likely to have their cancer diagnosed while it was in an early stage.
- 46 men in the screened group were diagnosed with advanced cancer, compared with 87 men in the unscreened group.
We have not yet had the opportunity to read the complete paper, so we cannot draw any major conclusions about the implications. However, one thing does seem to stand out — that is the 14-year follow-up that is built into this study and the clear distinction between the management of screened and unscreened men.
Recognized problems inherent in both the earlier major screening studies (the PLCO trial and the ERSPC study) — whose initial results were reported in the New England Journal of Medicine in early 2009 — were the relatively short period of follow-up and the fact that the trial protocols left a lot to be desired. (In the PCLO study at least half of the “unscreened” patient group was, in fact getting PSA testing outside the trial protocol; in the European study there were multiple different screening protocols being used.)
The “New” Prostate Cancer InfoLink will be able to comment on the current study with more intelligence just as soon as we can see a full copy of the actual study report.