Another story about a “new” screening test, this one for prostate cancer, the most common cancer in the US. This one looks for a particular combination of variations in five genes. If a man has all five and a family history of prostate cancer then his risk of is increased by a factor of nine. The researchers who have devised the test have also patented it and plan to sell it for $300 bucks a pop. I, for one, am not buying it (literally or figuratively). First some of the details as given by a press report:
Almost half of prostate cancer patients carry five genetic variations and a family history of the disease, says a breakthrough study in the search for a root cause of one of the most common and deadly tumors.
Having the combination raised the chances of getting the disease 9-fold, according to a study of 4,000 Swedish men published today by the New England Journal of Medicine. While each of the variations increased the cancer risk a small amount, putting them together gave the researchers the power they needed to generate a substantial and consistent finding, they said.
Researchers led by Jianfeng Xu, a professor of cancer biology at Wake Forest University School of Medicine in Winston- Salem, North Carolina, are working with a company, Proactive Genomics LLC, to sell a $300 test based on the findings. (Bloomberg)
I’ve already had a prostate screening test, the prostate specific antigen (PSA) blood test. In fact I’ve had a couple of them. I don’t plan to have any more. Why? Because the PSA is too sensitive and not sufficiently specific. It produces quite a few false positives in the sense that it doesn’t differentiate prostate lesions that are no clinical problem from those that are extremely aggressive and dangerous. And neither does this test. I can’t see what advantage it has over a PSA (which I find so unsatisfactory I have decided not to get any more). It’s even worse. It doesn’t say a thing about whether there is a lesion there or not, just the risk of a lesion. You’d have to have the same test (a PSA or digital rectal exam) as a follow-up.
This work isn’t worthless. If we know what genetic elements are involved they might provide important and useful clues to causes of prostate cancer. And of course it is certainly worth quite a bit to the folks who will be hawking this to the worried well. But spending $300 for no tangible benefit?