Prostate Cancer Risk Screening

"Should I get a PSA test?" My patient was giving me a run for his money during his annual exam last week. We'd already discussed the pros and cons of undertaking treatment for blood pressure, and he'd asked for the evidence why one medication was preferable to another. He wanted to know if the data I presented was from studies sponsored by dirty drug company money. Finally, he threw out this challenge to conventional wisdom on prostate cancer screening, and a very good question it was.

Men anticipate prostate cancer screening with all the dread that women bring to Pap tests. Screening is generally limited to men over the age of 50 (unless there is a history of early prostate cancer in a father or brother) and consists of an exam of that part of the prostate that can be reached by a probing finger plus a blood test for prostate specific antigen or PSA.

The problem is that the PSA, while being the only cancer marker test currently available for screening purposes, is not specific. In other words, most men with an elevated PSA do not have cancer. The digital exam is even less specific as many aging men have enlarged prostates without harboring cancer. Other screening deficiencies in our current approach of one blood test and one finger exploration include:

• Most men with prostate cancer (85% in one study) detected by PSA screening could avoid therapy. Per another study, one would have to screen 1400 men and perform 50 prostatectomies to prevent one death from prostate cancer.
• There is no PSA level below which the risk of cancer is zero. The Prostate Cancer Prevention Trial (PCPT) found cancer in 6.6% of men with PSAs below .5 and 12.5% of those men had aggressive cancer.
  
• Other factors seem to affect PSA levels, e.g. obesity and statin use lower PSA.

So what's a guy to do? One study over nearly 9 years showed a 20% decreased risk of cancer death with PSA screening every 4 years vs. none at all. Another concluded that testing every 6 years with digital exams every 4 made no difference whatsoever. Dr. Eric Klein notes(1): "All cases of prostate cancer are clinically relevant in that they can cause anxiety or can lead to treatment-related morbidity." In other words, we are detecting a large number of sub-clinical tumors--i.e. no symptoms suggest a prostate cancer brewing--with our screening, many of which would never cause a problem. We know that 90% of men with low-grade prostate cancer choose treatment which can cause incontinence, impotency, or death.

Dr. Klein suggests one approach to screening that uses seven variables to predict a man's risk of currently having prostate cancer. This test can be found at PCPT risk calculator.
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1. Klein, EA. What's new in prostate cancer screening and prevention? Cleveland Clinic Journal of Medicine. Vol 76 August 2009 439-445.

Floppy Eyelid Syndrome

You're probably thinking well shoot, I've already got that. You may well have saggy eyelid syndrome--you know, look in the mirror, gently shove the skin below your eyebrows off your upper lids and poof, the young, wide-eyed ingenue reappears. But this is FLOPPY Eyelid Syndrome, first described in 1981 by two researchers checking out the lids on middle-aged obese men. Associated with sleep apnea, this lizardish look not only includes the saggy lidded thing but also redness and irritation in the no-longer-so whites of the eyes.

We know that sleep apnea can seriously affect the heart (right-sided failure) and brain (increased risk of small vessel disease and 'mini' strokes). But why the eyes? Some investigators feel the cause is mechanical stress--i.e. smashing and stretching the eye against pillow--which is supported by the fact that one-sided sleepers often get one-sided F.E.S. Others wonder if alternating ischemia (not enough oxygenated blood) followed by reperfusion (flood of oxygen-rich blood when the apnea ceases) results in tissue inflammation. Studies of floppy lids (what happened to the sleeper upon which these lids resided!?!) showed an inflammatory injury reaction consistent with both stress and ischemia as seen in other tissue types.

Not only does F.E.S. limit the field of vision (while providing, perhaps, some sun protection in a visor sort of way), but the redness and irritation along with that iguana image may necessitate a surgical lid lift, one that the insurance company would be willing to fund!

Shining light on prostate cancer risk...

UV light that is. I've mentioned previously that vitamin D is a chemopreventive agent against several types of cancers. North Carolina investigators wondered if exposure to sunlight early in life has a more potent protective effect against prostate cancer than fun in the sun later in life.

They examined data from the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study*. Using solar radiation in the state of birth as a measure of sun exposure in early life, the researchers looked for correlation between childhood sun exposure and subsequent development of prostate cancer in adulthood.

Men born in regions with high solar radiation had half the prostate cancer risk compared with men born in cloudier regions. Those who moved away from overcast skies to sunnier climes as adults halved their risk of fatal prostate cancer although their overall prostate cancer risk remained the same as peers who stayed with the gray.
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*Cancer Epidemiology Biomarkers & Prevention 16, 1283-1286, June 1, 2007.