Tag: Cancer

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Good News About Cancer in Canada

Almost every household has had a brush with cancer. That means nobody is immune to it. Diagnosis of cancer brings with it tremendous psychological and physical burden to the patient and patient’s loved ones. Therefore, it is important for each one of us to learn something about the common cancers and how to prevent them.

Good news about cancer is that half of all new cancer cases and cancer deaths worldwide are preventable. The second good news is the 5-year relative survival ratio was 62 per cent for all cancers combined from 2001 to 2003. Some years ago it used to be around 50 per cent.

Each year, Canadian Cancer Statistics review the changing size and nature of the cancer burden in Canada. An article in the Canadian Medical Association Journal (CMAJ • November 18, 2008) reviews the major findings from the 2008 edition of Canadian Cancer Statistics.

The article says, “In Canada, cancer will develop in 45 per cent of men and 39 per cent of women during their lifetime, and about one in four Canadians will die of the disease.” There is a higher incidence of cancer among women aged 20-59 years. The mortality rates among women in their 30s and 40s are higher than among men of a comparable age.

Breast cancer is the most prevalent cancer among Canadian women, about one per cent of women. Among men, prostate cancer is the most prevalent cancer, about 0.8 per cent of men.

Thyroid cancer had the highest estimated 5-year relative survival ratio, and pancreatic cancer had the lowest. In general, the incidence rate has been stable for all cancers combined since 1979. In contrast, the mortality rate is decreasing for all cancers combined and for most specific types of cancer. That means we are making slow progress. But we can do more to decrease the incidence of cancer and increase survival if we take more care of our health, take preventative measures and participate in screening protocols.

Breast cancer

The incidence of breast cancer has fluctuated in the last 20 to 30 years due to screening mammography picking up cancer not previously detected. Now the incidence is stabilized to pre-screening years. Good news for women is that in the last 23 years the mortality rate for breast cancer has fallen by more than 25 per cent. Thanks to screening mammography and use of chemotherapy after surgery. Isn’t that wonderful?

Prostate cancer

The incidence rate of prostate cancer continues to increase moderately. Since the mid-1990s, mortality rates have declined by 2.9 per cent per year, likely because of a combination of earlier detection and improved treatment.

Colorectal cancer

The incidence rate of colorectal cancer, particularly among women, has recently begun to decline. The mortality rate has been falling among both men and women over the past two decades, likely as a result of improvements in chemotherapy.

The article says that screening for colorectal cancer can reduce both the incidence and mortality. Limited screening activity has already been occurring in some provinces, which may account for some of the decline in mortality.

Lung cancer

Among men, the incidence and mortality rates began to decline in the mid-1980s. Among women, incidence and mortality rates have been increasing since at least 1979, and continue to do so (each by 1.2 per cent per year). Overall, the incidence continues to be higher among men than among women. The mortality is also higher among men than among women.

The review shows the 5-year relative survival for cancer has been improving over time. Two of the most common types of cancer, lung and colorectal cancer, the survival rates are poor to fair. Most lung cancers are preventable if you do not smoke. For colorectal cancer, implementation of screening programs in many provinces is expected to improve survival.

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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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