Prostate Cancer: Experts Discourage Vitamins and PSA Test
Oct. 11--For health-conscious men of a certain age, what could be more prudent than taking vitamins and getting screened for prostate cancer?
Not doing those things.
That's the disillusioning take-home message from back-to-back reports on prostate cancer, the malignancy diagnosed in one out of every six American men.
A major national study in Wednesday's Journal of the American Medical Association concludes that selenium and vitamin E supplements do not ward off the disease-and vitamin E alone can somehow promote it.
Less than a week ago, an influential federal panel recommended against screening with the prostate specific antigen (PSA) blood test. The "vast majority" of men treated for PSA-detected tumors do not prolong their lives, yet that treatment subjects them to "significant harms," including urinary, sexual, and bowel problems, the U.S. Preventive Services Task Force said in a draft of updated recommendations.
The advice -- which the panel said applied even to high-risk men such as African Americans -- was immediately criticized by medical and advocacy groups.
Fox Chase Cancer Center oncologist Paul Engstrom -- a leader of the vitamin study who also happens to be a prostate cancer survivor -- tried to take the long view. What is needed, he said, is a way to distinguish life-threatening tumors from relatively harmless ones. Currently, biopsied tumor tissue is analyzed in a lab, but doctors can't say with confidence which cancers need not be treated.
"We don't have an effective biomarker to separate out bad cancers" from the ones that would never become lethal, he said.
Whether such a test is on the horizon depends who you ask. But there is a consensus that efforts at prevention and early detection -- the bywords of the war on cancer -- have complicated the fight against prostate cancer.
Even the Prostate Cancer Foundation, which supports routine PSA screening, praised the task force for heightening awareness of the harms of "overdiagnosis and overtreatment of indolent prostate cancers."
To save one life, so many men have to be treated that the average cost of diagnosis and treatment is over $5 million per patient, according to the foundation, created by business magnate Michael Milken after his own successful battle with the disease.
Driving those costs are ever-fancier treatment technologies -- not necessarily with superior outcomes -- including robotic surgery, image-guided pinpoint radiation, and proton therapy, said Paul B. Gilman, chief of hematology/oncology at Lankenau Medical Center.
Gilman and researchers at more than 400 sites across the U.S. and Canada recruited patients for the vitamin study, hoping that boosting selenium and Vitamin E would be a low-tech, low-cost prostate cancer prevention tool. Circumstantial evidence suggested the supplements would help with prostate cancer. Never mind that vitamins had been disappointing in most other prevention studies, including one that found Vitamin A actually increases lung cancer risk in smokers.
Beginning in 2001, more than 35,000 healthy men over age 50 were randomly assigned to take selenium, vitamin E, both supplements, or placebo.
In 2008, the men were told to stop taking their pills because it was clear the government-funded experiment was not curbing prostate cancer. In fact, the Vitamin E group had a few more cancers than expected, although it might have been coincidental.
By May of this year, it was clearly not coincidental; Vitamin E increased the risk of prostate cancer by a small but significant 17 percent. The placebo group had 529 cancers. That compared to 620 who took vitamin E, 575 who took selenium, and 555 who took both supplements.
The implications of the finding are "substantial," given that more than half of Americans age 60 and up take vitamin E supplements, the researchers concluded.
"The results basically tell us that, while we all have the impression that vitamins are good and more must be better, we need to be cautious," said Leonard Gomella, chair of urology at Thomas Jefferson University's Kimmel Cancer Center, which enrolled 40 men in the study.
PSA screening is a far thornier debate.
The level of PSA, a protein shed into the blood by the prostate gland, rises when cancer develops, but also with benign conditions such as an enlarged prostate -- and aging. Even with a "normal" PSA level, cancer can't be ruled out, yet setting the cut-off lower increases the number of men who undergo biopsies only to find nothing. Experts continue to debate where to set the PSA cut-off, and how much to rely on abrupt changes in PSA levels rather than absolute numbers.
Another conundrum involves how to define "harms."
To be sure, radiation and surgery often leave men with permanent complications. Impotence, urinary incontinence, and, less often, bowel dysfunction affect "at least 200 to 300 of 1,000 men treated," the task force said.
But the alternative to PSA-based early detection is "clinical detection"-diagnosing the cancer when it can be felt by a doctor, or causes symptoms such as trouble urinating, blood in the urine or semen, pelvic discomfort, or bone pain.
Before PSA testing became standard in the early 1990s, 70 percent of men were diagnosed with prostate cancers that had outside the walnut-sized gland or to distant organs.
Now, studies show, fewer than 3 percent of men have metastases when diagnosed.
While the task force didn't explicitly say that men would be better off being diagnosed at advanced stages, that's how doctors and patients alike read between the lines.
"We are not getting enough credit for improvements in treatment side effects," said Gomella at Jefferson. "And done properly, PSA does save lives. We don't want to be getting PSA tests on 85-year-old asymptommatic men. But to say that all men should not be screened is such a step backwards."
Gomella advocates "active surveillance" to monitor prostate cancer that is not an immediate health risk. It involves frequent PSA tests, ultrasound scans, and biopsies to watch for worrisome changes -- a strategy that others say is not much different from old-fashioned "watchful waiting."
Fox Chase's Engstrom, whose cancer was diagnosed 15 years ago because of an elevated PSA level, admits to "built-in biases" about the test. Now 75, he had "a very good outcome with surgery."
But like many physicians, he sees a middle road, one that neither may lead to the test -- or not. He believes each man should decide after being counseled about the potential risks and benefits of the test, based on their age, race, family history, and personal fears.
"Obviously, it's a lot easier to say everybody should have the PSA test," Engstrom said. "But the decision to needs to be individualized."
Contact staff writer Marie McCullough at 215-854-2720 or firstname.lastname@example.org.
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Posted: October 2011
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