Tag: prostate

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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Another prominent Canadian, 53-year-old federal Health Minister Alan Rock, has been struck with prostate cancer. The recent famous Canadians in the news with prostate cancer were Pierre Trudeau and Preston Manning.

In the last one-year, we have discussed prostate cancer in this column at least twice. The last one was as recently as two months ago. After the column appeared, a reader asked several questions. These will be answered today.

The reader also adds, “It is often important to get down to very basics of human body when we talk about this stuff – without making someone gag on his cornflakes in the morning, of course!” Let’s see what we can do!

Is Medicine Hat high in prostate cancer?

According to Alberta Cancer Board (ACB) document (Cancer in Alberta – A Regional Picture – June 2000) the incidence of prostate cancer seems to be higher in the south and lower in the north. But this is not a real increase. This may reflect different patterns of PSA testing in the province, although other explanations are possible.

The higher proportion of older adults in our region compared to other regions in Alberta will contribute to greater number of cancer cases in this region but this should not affect the region’s cancer rates, says the ACB document. So, there is no real increase in prostate cancer incidence in our health region.

What does prostate gland do? What happens if it is removed? Do we need the prostate? Why not remove it if all men are eventually going to get cancer?

The main function of the prostate is to provide the proteins and ions that form the bulk of the semen. Prostate produces enzymes like acid phosphatase and prostatic specific antigen (PSA). A normally functioning prostate is important for normal reproductive function. In conjunction with other smaller glands in the vicinity, the prostate gland produces secretions that serve to lubricate the system and provide a vehicle for storage and passage of sperms.

Yes, we need the prostate gland as it has important functions. Most people survive the removal (part or whole) of the prostate gland with no or minimal complications. But a small percentage of patients end up with urinary incontinence and impotence. So I am not sure if prophylactic removal of the gland would be acceptable to many people.

Where is the prostate gland?

The prostate gland lies below the urinary bladder in front of the lowest inch of the rectum, through which it can readily be felt on digital rectal examination. The gland is only present in men. The urethra from the bladder passes through the gland before it enters the penis. The gland has an important role in proper flow of urine.

In summary, the prostate, a small gland weighing only 20 g in a young man, becomes increasingly irrelevant with age, is eventually a nuisance to almost all men and, by the end of the average male life span, has a 70 per cent chance of harbouring malignant cells. Prostate cancer is about fear, sex, indignity and death (Canadian Medical Association Journal). But we can change it by regular PSA testing and digital rectal examination.

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Dear Dr. B: Pierre Trudeau died of prostate cancer. At the age of 58, Preston Manning is diagnosed to have prostate cancer. Can you please tell me something about prostate cancer – especially prevention and early detection? Yours: Mr. Worried.

Dear Mr. Worried: Let us start with bad news first. Every man, who lives long enough, will develop prostate cancer. The risk of getting prostate cancer increases rapidly after the age of 50. In fact, by age 75, the risk of getting prostate cancer is 30 times higher than age 50. But the good news is: if the prostate cancer is detected early then it can be cured.

How common is prostate cancer? If you take 100 men age 50 or older, 30 will have prostate cancer, 10 will be diagnosed with and treated for prostate cancer, and three will die from it. According to the National Cancer Institute of Canada (1996), prostate cancer is the most frequent cancer and the second leading cause of death from cancer in men, exceeded only by lung cancer.

According to Alberta Clinical Practice Guidelines, there are four major risk factors for prostate cancer: age, race, diet and family history.

Age: this has been discussed earlier. Race: African-American men have a 30 percent greater incidence of prostate cancer compared with white men. Diet: a high intake of dietary fat also seems to be associated with a higher risk for developing prostate cancer. Family history: there is an increased risk for the development of prostate cancer in men who have first-degree relatives with the disease.

How do I know I have prostate problems?

If the prostate is large enough to partially block the flow of urine, then there is diminished urine flow (Doc, I cannot hit the wall!); delay in onset of urine flow (honey, don’t rush me!); and frequent urination (sir, when is the next bus stop!) especially at night (oh boy, a man has to go when he has to go!). The enlarged prostate can be due to benign prostatic hypertrophy (BPH) or prostate cancer.

Does it mean that if I don’t have any symptoms then I do not have prostate cancer?

No, that is not true. You may be harbouring cancer in the prostate gland without any symptoms. That is why there is a big drive to screen asymptomatic men over 50 with digital rectal examination (DRE) and prostate specific antigen (PSA) blood test.

Although digital rectal examination 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. So it has a double advantage. PSA blood test has a false positive rate of 20 to 50 percent and false negative rate of 25 to 45 percent. That is means 30 to 50 percent of the time the test is wrong! So, why do them? The reason is simple – this is the best shot we have to get an early diagnosis!

What about prevention? Preventive strategies for prostate cancer are same as any other cancers. The Canadian Cancer Society recommends the following: stop smoking, eat low-fat, high fibre foods, and exercise regularly, limit salts, alcohol, and caffeine intake.

DRE and PSA is the best we have to make early diagnoses. So, Mr. Worried, talk to your doctor and get yourself checked out!

Start reading the preview of my book A Doctor's Journey for free on Amazon. Available on Kindle for $2.99!