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 havent 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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