Sunday, February 10, 2019

Should I/he get a PSA test?

Should I have a PSA test?
I expect a lot of feedback on this, as data tends to be overwhelmed by “My (brother-in-law/ golf partner/ accountant) says that the PSA test saved his life.” Read on and react if you wish.
Prostate cancer is the commonest cancer in men (other than low-grade skin cancers), with an estimated 165,000 new diagnoses of prostate cancer in American men in 2018 and about 29,000 deaths. It is increasingly common as men age and at the same time, less likely to lead to death because it is usually a slow-growing cancer. Thus, while it is estimated that the average American male has a 16% risk of developing prostate cancer in his lifetime, he has only a 2.9% risk of dying from it. I would tell my older male patients that if you were to pull all the men over 75 off the golf course and biopsy their prostates, the majority would have cancer. The best data we have shows that by age 80, approximately 60% of men have prostate cancer, but that in most it grows so slowly that they will die of something else before the disease causes any problem.
Historically, prostate cancer was diagnosed by feeling the gland via rectal exam, but this is a very poor way to detect it and certainly useless at picking the disease up early. The approach was dramatically changed when PSA (prostate-specific antigen) came into use as a screening test. There are normally detectable PSA levels in all adult males, and the level rises gradually with age (and the expected enlargement of the prostate that accompanies aging), so the dilemma is in deciding the level that makes cancer likely. Further complicating things is that conditions other than cancer raise the PSA, notably prostatitis (infection of the gland). Both bicycle riding and the rectal prostate exam itself can raise PSA, but usually not by much.
The traditional teaching was that PSA levels under 4 were normal, 4-10 suspicious and over 10 probably cancer, but this simple classification has been questioned. There is no level of PSA that guarantees no cancer, and very big but non-cancerous prostates may have PSA levels over 10. The tradeoff of using lower levels is that fewer cancers are missed but many men who have no cancer will be subject to biopsy. Neither the speed at which the PSA is rising nor the ratio of free to total PSA are definitive enough to give strong recommendations. Hence, if you opt to have your PSA tested, you are accepting the possibility of needing a biopsy. Prostate biopsies are done via the rectum and have been likened to being kicked in the groin by a mule. Multiple samples (8 to 12) are taken and the results are used to calculate a “Gleason score” that grades the cancer and indicates the likelihood of dying from the cancer. There is a small (about 1%) risk of serious infection from a biopsy and similar risk of bleeding
Treating prostate cancer has its own problems. Surgery carries a high likelihood of erectile problems and incontinence of urine, while radiation therapy can cause bowel issues and urinary flow problems.
Multiple studies have been done to estimate the value of screening for prostate cancer, and the results are, to be charitable, inconclusive. A large European trial found that screening would result in 0.7 fewer deaths for every 1000 men screened, while a similar American trial found no difference between men screened and men not screened.
OK then, what should you do? Different groups give different answers, but there is a growing consensus not to screen men over 70 because doing so is unlikely to prolong their life. There is also agreement that it is not worth doing in men under 40 because the disease is so rare. Between 40 and 50 prostate cancer remains rare except in African American men and men with a family history of prostate cancer below age 65, who should follow the same logic as those over 50. For men 50-70, the decision is a classic example of “shared decision making.” Each man will have his own viewpoint on whether the small decrease in mortality is worth the risks of both diagnosis and treatment. In an ideal world, each man would sit down with his doctor and discuss all the issues, but in this day of 10-minute office visits, that is hard to do. Instead, I would suggest you look at one of the web sites that let you explore the pros and cons. My favorites are:
https://www.cdc.gov/cancer/prostate/index.htm
https://www.mayoclinic.org/tests-procedures/psa-test/in-depth/prostate-cancer/art-20048087

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2 comments:

  1. I am 71. I will have the PSA test, even if I have to pay for it out of pocket.

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    Replies
    1. Go for it - as long as you have your eyes open. I've stopped.

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