PSA and Prostate Cancer

Does PSA screening reduce death due to prostate cancer?

PSA-based screening for prostate cancer remains a controversial issue, says an article in the Canadian Medical Association Journal (CMAJ).

Some health authorities in the United States advocate prostate cancer screening in men who ask about the PSA test. On the other hand, the Canadian Urological Association and most health authorities in the European Union still discourage the practice of prostate cancer screening, says Dr. Andre N. Vis, author of the CMAJ article.

In the United States, there was a gradual increase in the death rate from prostate cancer over several decades. But since 1993, the death rate from prostate cancer has gradually declined by 17.6 percent. Same thing has happened in Canada. Between 1991 and 1996, the death rate has declined by 10 percent.

Here is another example. Quebec experienced a 47 percent increase in the incidence rate of prostate cancer between 1989 and 1993. Probably due to introduction of PSA test. And the rate of prostate cancer death rate in Quebec decreased by 15 percent between 1995 and 1999.

The question is – is this decline in the death rate due to the effectiveness of screening with the PSA test? The PSA test was introduced in North American medical practice by the end of 1980s.

Some experts believe that the decline in the death rate from prostate cancer is due to better treatment options, change in diet and lifestyle, and may be improvement in environmental conditions. Not due to PSA screening.

Linda Perron and associates who did the research on the effectiveness of PSA screening in Quebec, says that, “In accordance with the observational studies described here, our results do not support the hypothesis that the present decline in prostate cancer mortality is attributable PSA screening.”

Perhaps the jury is still out on the effectiveness of screening for prostate cancer by PSA test. That does not mean that we should ignore our prostate. Thirty percent of men over 50 will have prostate cancer, but only 10 percent of these men will be diagnosed and treated for prostate cancer and three percent will die of the disease.
That means we have to be vigilant. We have to use whatever methods we have to detect prostate cancer early and treat it. And the methods of early detection available to us are two: digital rectal examination (DRE), and PSA blood test.

If you don’t have any symptoms of prostatic cancer does not mean you don’t have prostate cancer. That is why there is a big drive to screen asymptomatic men over 50 with DRE and PSA blood test.

Although DRE has a cancer detection rate of only 0.8 to 7.2 percent, it remains an important test that can be done easily in a doctor’s office. It also checks for anal and rectal tumours.

PSA blood test has a false positive rate of 20 to 50 percent and false negative rate of 25 to 45 percent. That means 30 to 50 percent of the time the test is wrong! So why do these tests if the returns are this low? The reason is simple – this is the best shot we have to get an early diagnosis!

If you are 50 years or older, and if you want to have your prostate checked out – in fact you should get it checked out – then talk to your doctor about digital rectal examination (remember, if you don’t let your doctor put a finger in your rectum to check your prostate then he might end up putting his foot into it!) and PSA blood test.

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