There was a four-fold increase in PSA testing in the Republic in 1999-2004 compared with Northern Ireland, despite guidelines which clearly recommend against screening for prostate cancer, writes MUIRIS HOUSTON
I HEARD something that bothered me last week. A male patient in his 40s went to his local general practice to have routine bloods to check on a pre-existing condition. As the blood began to flow from his arm vein through the needle, the practice nurse casually announced that she was also taking blood to check his PSA levels, “while she was at it”.
The patient was not impressed. Should she not have asked his permission? Should she have first explained the test and what it was for? And what concerned him most of all was the lack of counselling to explain the implications of a raised PSA test and where it might lead to in terms of further investigations.
I was bothered about the story on a number of fronts. But when the latest all-Ireland 10-year cancer report was published later in the week, and I read the detail on prostate cancer, my concerns crystallised around our laissez- faire attitude to screening for the disease in the Republic.
According to the report, “total cancer incidence rates were 10 per cent higher for men and 2.2 per cent higher for women in the Republic of Ireland compared with Northern Ireland. The difference for men was mainly due to differences in prostate cancer diagnosis through increased testing in the Republic.”
The authors note there is considerable variation in the use of PSA testing (for prostate cancer) between North and South.
The large difference in the incidence of prostate cancer between Northern Ireland and the Republic may at first glance seem alarming.
However, the greater number of cases among males in the Republic does not mean that men south of the border are exposed to some mystery risk factor.
The primary reason for the discrepancy is the greater amount of PSA testing done in the Republic. PSA testing means the diagnosis is made closer to the time the cancer first develops, which in turn increases the apparent survival time from diagnosis to death.
But, in fact, the time from the development of the cancer to a person’s death does not change.
In addition, most men diagnosed with cancer do not die from the cancer but as a result of another disease, a reflection of the very slow growth of most prostate cancers.
The National Cancer Registry in Cork published an interesting study in January which sheds some light on why doctors in neighbouring countries could have such different practices.
A survey of 1,625 GPs in the Republic found that 79 per cent would use PSA to test asymptomatic men for prostate cancer.
Doctors who ran “well-man” clinics and who carried out occupational health checks were more likely to use PSA testing.
Interestingly, given the patient experience I outlined earlier, practices which performed other tests routinely with a PSA were more likely to test for prostate cancer.
The authors noted a four-fold increase in PSA testing in the Republic between 1999 and 2004 compared with Northern Ireland.
It seems doctors in the North work more closely to guidelines which clearly recommend against screening for prostate cancer.
The NCR study concluded: “the belief of GPs in the clinical utility of PSA testing in asymptomatic men, despite the lack of evidence that it improves outcome, has many implications for policymakers”.
Last week’s data raise some interesting questions. Do doctors in the Republic need better guidelines to rectify their over-testing for prostate cancer? Are they referring men with lower blood levels of PSA to urologists than their colleagues in Northern Ireland? And are specialists in the North less likely to biopsy a man referred to them with an elevated PSA?
The cancer registry data suggests that population screening for prostate cancer cannot be justified, in line with recently published international studies and with the 2006 national cancer forum report.
For the individual requesting a PSA test, it suggests he may end up being told he has a disease that is not causing him any symptoms and which will not shorten his life. And for the person who has a blood test taken without informed consent, it means opening an entire can of worms he doesn’t wish to have anything to do with.
Dr Houston is pleased to hear from readers at mhouston@irishtimes.com but regrets he cannot respond to individual medical queries