Tag: prostate cancer

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Role of Calcium and Milk Products in Prostate Cancer

Dear Dr. B: We are in Arizona for the winter. My husband and I have always taken calcium and Vitamin D. There seems to be a lot of controversy here with several people who feel that calcium for men is putting them at high risk for prostate cancer.
Apparently this warning was on T.V. and in the newspapers. What is the truth, doctor?

Answer: Nobody knows exactly what causes prostate cancer. There are a variety of factors implicated in this process. There are some factors (diet and weight) you can change but others like age, ethnicity and family history cannot be changed.

As we know, prostate gland is present only in man. Any normal man can develop prostate cancer because normal men have male hormones (testosterone). Lack of testosterone due to any cause can reduce the risk of prostate cancer.

Age is an important factor. Prostate cancer is rare before the age of 45. As one gets older, the risk increases. Men of African or Caribbean ancestry have the highest risk.

What has race to do with prostate cancer? Scientists are not sure about that. There may be subtle genetic, dietary, environmental and hormonal differences. Another interesting fact is that dark skin absorbs less sunlight than light skin, which may contribute to the higher incidence of prostate cancer among men of African or Caribbean ancestry because of lack of vitamin D.

Family history is important. If your father or brother has had prostate cancer you are approximately two to two and half times more likely than the average man to be diagnosed with the disease during your lifetime. Having two first-degree relatives with prostate cancer increases your risk to about five to 10 times that of a man with no family history, and your risk soars to almost 100 per cent if three or more first-degree relatives have had prostate cancer.

Diet is linked to prostate cancer. A low fat diet may help prevent prostate cancer. Foods rich in saturated fats have been associated with increased risk of prostate cancer, possibly because they are metabolized into testosterone. Fish oils may protect against prostate cancer especially omega-3 fatty acids found in fatty fish like trout, anchovies, bluefish and white albacore tuna.

What about the role of milk, cheese and calcium? The American Cancer Society website article of 2001says, “Experts say excessive calcium intake may be unwise in light of recent studies showing that high amounts of the mineral may increase risk of prostate cancer.”

Here is a dilemma. There is a reasonable evidence to suggest that calcium may play an important role in the development of prostate cancer but evidence also shows calcium may lower the risk of colon cancer and age-related thinning of the bones.

The recommended daily allowance (RDA) of calcium is 1,000 mg per day for men and 1,500 mg for women. Important thing to remember is the words, “excessive calcium intake.” It is also critical to remember that this evidence is not conclusive. The word “may” is used quite often in this context.

You can have milk, cheese and other dairy products in moderation. An 8-ounce glass of milk contains about 300 mg of calcium, an ounce of cheese has about 200 mg, and a serving of yogurt has about 312 mg of calcium. Men should stay within 1000 mg of calcium per day. And don’t forget your vitamin D 1000 to 2000 IU per day especially in winter months. Vitamin D has an important role in preventing prostate cancer and other cancers.

A balanced diet, combined with regular exercise, is always a good idea.

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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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