Did you know…

Did you know the death rate for breast cancer for Canadian women has dropped by 25 per cent since 1986?

A Canadian Cancer Society special report in Canadian Statistics 2007 says increased participation in organized breast screening programs (particularly by women aged 50 to 69) has led to earlier detection and made it more likely that patients who have breast cancer receive successful treatment (CMAJ June 19, 2007).

The national recommendation is that organized breast cancer screening programs actively screen women aged 50 to 69 every two years. Organized screening programs began in British Columbia in 1988 and have since expanded to include all provinces, the Yukon and the Northwest Territories.

If you are under 50 years of age or 70 and over then discuss your risks and screening program with your physician.

The screening program includes mammogram, clinical examination of your breasts by your physician every two years and monthly breast self-examination.

Did you know that early diagnosis and treatment of prostate cancer was first suggested a century ago?

Although prostate-specific antigen (PSA) blood test has been widely used in North America to detect early prostate cancer, it is still unknown whether PSA screening significantly reduces mortality from prostate cancer.

Actually PSA measurements reflect cancer risk, with the risks of cancer and of aggressive cancer increasing with the level of PSA (CMAJ June 19, 2007). Besides PSA blood level, your physician will look at other risk factors before he can advise you on further management. Other risk factors are: family history of prostate cancer, digital rectal examination findings, age, ethnicity and history of previous biopsy with a negative result.

Since PSA test is not a perfect test for detecting early prostate cancer, you should discuss with your doctor the risks and benefits of ordering such a test. PSA blood test for screening is not recommended by the Canadian Task Force on Preventive Health Care as there is insufficient evidence to promote it for screening for early detection of prostate cancer. Canadian Urological Association and Prostate Cancer Alliance have recommended that it be performed only after detailed discussion of the pros and cons between doctor and patient.

What is interesting is that recent nationwide survey indicated that almost half of Canadian men over 50 years of age reported receiving PSA screening during their lifetime. PSA blood test and digital rectal examination have become part of annual physical examination for men over 50 by their family physician and 72 per cent of these men had these tests in the last one year (CMAJ).

Prostate cancer is thought to be the disease of older men. But autopsy studies have found that 27 per cent of men in their 30s and 34 per cent of men in their 40s have histological evidence of the disease (not necessarily clinically known disease). The current lifetime risk of disease diagnosis is 18 per cent and lifetime risk of dying from prostate cancer is three per cent.

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Prostate Cancer Tests


Dear Dr. B: Can you please tell me about the new test under development for early detection of prostate cancer?

Answer: I received this question from a friend whose style of writing and sense of humour I enjoy. The e-mail contained a comment on my last column on aspirin and colon cancer and the photograph accompanying the article showing a flexible sigmoidoscope. Here in part is what my friend said:

‘Imaginative photo. We amateurs still squirm about such “personal” things and, I’m sure, men more than women, are real wimps about poking around the body. Of course, to a medical person it is a smart surgical instrument used in an everyday procedure. To a patient it is perceived as a fire hose up the whazoo… Just the other day I was discussing, in a casual conversation, the old finger-vs.-PSA test… Today, through bleary eyes, I read a piece in the Globe about new research and new tests under development. I know you’ve hit this before. But it might be worth a visit to this subject again some time.’

My friend is right. It is time to revisit the subject because prostate cancer is the most frequent cancer and the second leading cause of death from cancer in men, exceeded only by lung cancer. In our region, 80 to 90 new cases of prostate cancers are diagnosed each year. And each year 10 to 15 patients die of the disease.

The walnut size 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 has an important role in the proper flow of urine. It also provides the proteins and ions that form the bulk of the semen. In conjunction with other smaller glands in the vicinity, the prostate gland produces secretions that serve to lubricate the reproductive system and provide a vehicle for storage and passage of sperms.

Once upon a time, “the old finger” i.e. digital rectal examination (DRE) was the only crude way to pick up early prostate cancer. 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.

Then came the PSA blood test. PSA was expected to replace the embarrassing and uncomfortable DRE. And it was promoted as an ideal test for screening and early detection of prostate cancer. But this hope has not materialized.

Now a group of researchers from the University of Michigan Medical School are working on a test which would use the body’s own immune system to detect prostate cancer early. That makes sense as the immune system, in response to cancer, releases thousands of chemicals into the bloodstream to destroy the tumor.

The new blood test looks for 22 of these chemicals that specifically fight prostate cancer. The preliminary report indicates that these chemicals are more reliable than PSA in detecting prostate cancer. But the bad news is that it will be several years before this test is perfected and marketed for everyday use.

In the meantime, we have to rely on “the old finger” and PSA test. Findings from a new national research study released recently by the Prostate Cancer Research Foundation of Canada (PCRF) found very few Canadian men are willing to discuss prostate cancer and PSA test with their family doctors. PCRF has launched a campaign with a slogan “Don’t Get Scared. Get Tested.” More information can be found on PCRF website, www.prostatecancer.ca.

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PSA and Prostate Cancer

Dear Dr. B: Recent reports on PSA and prostate cancer have really confused me. Can you please tell me about the tests required for early detection of prostate cancer and where does PSA fit in?

Dear Reader: You are not the only one who is confused. PSA-based screening for prostate cancer has always been confusing and controversial. Even doctors are confused!

I am into my seventh year of writing these columns. And looking back I have written at least five columns on PSA and prostate cancer. And we haven’t heard the last word on it.

Let us look at the recent media attention given to PSA and prostate cancer. An article published in the New England Journal of Medicine (NEJM) asks: What is the prevalence of prostate cancer among men with low prostate-specific antigen (PSA) levels?

Currently, the cut off point for PSA level is 4 ug/L. If the PSA level is 4 ug/L or more then the patient is referred for a biopsy of the prostate gland to check for cancer.

Some experts have argued that this cut off point is high and we may be missing lot of cancers in patient whose levels are lower than 4 ug/L.

The NEJM article reports on the results of PSA levels and prostate biopsy done on 2950 men who completed the seven-year-trial. The study found that the risk of cancer increased with increasing PSA level, from 6.6 per cent for levels of 0.5 ug/L or less to 26.9 per cent for level of 3.1 to 4.0 ug/L.

It has been estimated that by using the current cutoff point at 4 ug/L we will miss up to 82 per cent of cancers in younger men and 65 per cent of those in older men. This finding is the most recent reminder that that PSA measurement is not a good screening test for early detection of prostate cancer.

Is there anything better? Unfortunately, no! It is suggested that monitoring the rate of rise of PSA levels over time may help. For example, if your baseline PSA is 1.0 ug/L and over a period of time it gradually increases then there may be an indication for prostate biopsy. This hypothesis has not yet been validated.

Prostate cancer is the most frequent cancer and the second leading cause of death from cancer in men, exceeded only by lung cancer. In our region, 80 to 90 new cases of prostate cancers are diagnosed each year. And each year 10 to 15 patients die of the disease.

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.

So, for early detection tests, what we have is better than nothing. The current tests are digital rectal examination and PSA blood test and they are still available. How often one should undergo these tests also remains controversial. But the best thing is to discuss your risk factors with your doctor and he or she can advise you accordingly.

Thought for the week:

“Success is that old A B C – ability, breaks, and courage.”

-Charles Luckman

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Prostate Cancer

Dear Dr. B: What is PSA? I believe this a blood test to check for prostate cancer. If this is true then why is my family doctor reluctant to order one for me? Can you please tell me more about this test, who should get it and how often? Yours, worried Mr. P

Dear Mr. P: PSA stands for Prostate-Specific Antigen. Yes, this test is now widely used for early detection of prostate cancer and to follow the progress of patients who have had prostate cancer.

Prostate cancer is now the most commonly diagnosed cancer in Canadian men and second most common cause of death from cancer in men. Prostate gland is present only in men at the junction of the urinary bladder and the urethra. PSA was thought to be produced and secreted solely by the cells of the prostate gland. But this is not true anymore. PSA is also found in breast cancer and other cancers.

Once upon a time, digital rectal examination was the only crude way to pick up early prostate cancer. Then came PSA blood test. PSA was expected to replace the embarrassing and uncomfortable digital rectal examination. And it was promoted as an ideal test for screening and early detection of prostate cancer. But this hope has not materialised. And the controversy continues.

In a recent edition of the Canadian Medical Association Journal, there are two commentaries on this issue. One is written by two family physicians and the other one by a urologist.

The family physicians feel that PSA testing in men over 70 should be avoided. They restrict the use of PSA screening to men between 50 and 70 years of age unless they are at higher risk (e.g. black American men and those with a family history), in which case screening is initiated at 40.

How often the test should be ordered?

According to the family physicians, the literature survey suggests that PSA should be ordered anywhere from every 2 years to every 5 years. Normal value should be less than 4 ng/mL. Another report suggests that men with PSA results of 4ng/mL and below should be tested every 6 months for at least 3 consecutive tests.

Currently, these family physicians recommend PSA every year for eligible patients but feel that screening every 5 years is a reasonable alternative.

The urologist’s commentary agrees that PSA testing for all men between 50 and 70 is a good idea. But PSA screening every 5 years may be inadequate. The urologist feels that yearly testing is reasonable unless the PSA level is below 1 ng/mL, in which case testing every 2 years is acceptable.

In about 20 percent of patients with normal PSA results, diagnoses of prostate cancer will be missed, which supports the idea that digital rectal examination is an important additional diagnostic tool. But digital rectal examination on its own will miss a substantial numbers of prostate cancers.

The urologist feels that the upper limit of normal (4ng/mL) may be too high and it would be prudent for family physicians to refer patients to a urologist if the PSA result is above 2.5-3.0 ng/mL.

So, Mr. P, have I confused you? If yes, then you are now on par with other doctors! The last word on this subject is yet to come. But I hope this information will help you put your doctor’s advice in proper perspective.

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