Men should weigh up benefits and harms of prostate cancer screening
MedWire News: Men at low to high risk for prostate cancer should fully consider the benefits and harms of prostate-specific antigen (PSA) screening before going ahead with the test, study findings show.
A balance-sheet model of analysis, developed by Australian researchers as a decision aid for patients and doctors, shows that screening men from 60 years of age onwards reduces the risk for prostate cancer-specific death.
However, “the net mortality benefit is small,” lead author Kirsten Howard, from the University of Sydney in New South Wales, told MedWire News, “and this needs to be weighed against the increased chances of being diagnosed and treated for prostate cancer.”
The study involved a hypothetical cohort of 1000 screened and unscreened Australian men, using Australian age-specific prostate cancer incidence rates from prescreening years 1982–1988, mortality rates in 2005 for screened and unscreened men, and data from the European Randomized Study of Screening for Prostate Cancer.
Published in the Archives of Internal Medicine, the results show that screening low-risk men, defined as those with no first-degree relatives affected by prostate cancer, annually from the age of 60 years will lead to 115 prostate biopsies after abnormal PSA test results, 87 of which will not find prostate cancer.
Over 10 years of screening, 53 men in the low-risk group will be diagnosed with prostate cancer compared with 23 men in the unscreened cohort.
The screened cohort will have 3.5 prostate cancer deaths, compared with 4.4 among the unscreened men, in the context of 116 deaths overall in the screened group and 117 in the unscreened group.
The researchers also looked at the impact on prostate cancer-specific and all cause mortality of screening men from age 40–69 years until age 85 years. They predicted 27.9 prostate cancer deaths and 639.5 deaths overall in the screened group, compared with 29.9 and 640.4, respectively, in the unscreened group.
Similar results were predicted for men in the moderate- and high-risk (one affected, and two or more affected first-degree family members, respectively) groups; however the men in these groups were more likely to receive a cancer diagnosis, undergo a biopsy, and undergo a biopsy after a false-positive PSA test result than those in the low-risk group.
Overall, the results show that participation in screening could mean a two- to four fold increase in risk for receiving a prostate cancer diagnosis, yet few affected men will actually die from the disease, indicating that men are being treated for clinically insignificant cancers, suggest the authors.
They acknowledge that most of the men who receive a diagnosis will be offered some form of cancer treatment, and that “the risks of these treatments in terms of adverse effects on quality of life are substantial.”
Howard said: “Data presented in our paper can readily be incorporated into patient decision aids to help men make choices about PSA screening, or can be used to inform clinical discussions with men considering screening.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009
By Sarah Guy