by Dr. Alan Inglis

If you're over 75 years old and some doctor is still trying to give you a PSA screening for prostate cancer, get a second opinion – fast.

More research has emerged that seriously calls into question the value of this already- flawed test for older gentlemen. You might recall that last year the U.S. Preventive Services Task Force urged doctors to stop giving the PSA to older men.

That didn't stop the practice, of course, even though the PSA has been a pretty lousy predictor of prostate cancer.

The overall mortality rate from prostate cancer has dropped only about 6 percent to 8 percent since PSA testing first began about 15 years ago. Meanwhile, the number of cancer diagnoses has more than doubled, resulting in a great deal of unnecessary treatment, cost, and suffering for many men.

The new research, conducted by the National Institutes of Health, looked at men over 75 and found that not one – let me repeat that, not one – died of prostate cancer if he had a PSA reading of under 3 nanograms per milliliter.

It's not that they found the risk was low – they found the risk was zero.

For men with PSA readings higher than 3 nanograms per milliliter, the study authors concluded there might be some value to continued screening, as these men are in a higher risk group.

Exactly how high that risk is, I'm not sure. Study after study shows that most forms of prostate cancer are very slow growing, and men with prostate cancer are likely to die of something else first.

At any rate, two-thirds of men over 75 have PSA readings below 3 nanograms per milliliter, which means that, for the vast majority of older men, this testing craziness can finally end.

It's about time.