Routine screening for prostate cancer has resulted in tumor diagnoses for more than 1 million U.S. men who otherwise might have suffered no ill effects from them, researchers said on Monday.
Prostate cancer screening is a double-edged sword, catching serious cancers in a few but causing needless worry and expense for the majority of men, who may be getting treatment for tumors growing too slowly to do any harm, the researchers said.
The team looked to see how many additional men have been diagnosed with prostate cancer since the introduction in 1986 of a widely used blood test for prostate cancer that looked for a prostate-cancer specific antigen, or PSA.
“Our estimate is that number is about 1.3 million people in the United States. That is a huge effect,” said Dr. H. Gilbert Welch of the VA Outcomes Group in White River Junction, Vt., whose study appears in the Journal of the National Cancer Institute.
More than 1 million of those were treated, they found.
“These are men who could not be helped by treatment because their cancer was not destined to cause them symptoms or death,” Welch said in a telephone interview.
The increased diagnosis rate more than tripled in men ages 50 to 59 and increased more than a sevenfold in men younger than 50.
And although prostate cancer deaths have declined since the introduction of PSA testing, Welch said about 20 men had to be diagnosed and treated for every one who benefited.
All current forms of treatment — surgery, radiation, and hormone therapy — can cause harm, resulting in impotence and incontinence in about a third of patients, Welch said.
A U.S. expert panel urged doctors last year to stop screening men older than 75, but doctors still disagree about the right approach to PSA screening. Two large studies — one in Europe and one in the United States — that aimed to settle the matter produced conflicting results.
Instead of discarding the PSA test, one solution may be simply to watch and wait for signs the tumor is growing. A study of more than 51,000 men published in the Journal of Clinical Oncology on Monday found that men diagnosed with low-risk tumors who waited were still doing fine an average of eight years after diagnosis — and some as many as 20 years later.
If that were the standard approach for low-risk cancers, “it might help us avoid throwing the baby out with the bath water when it comes to the PSA test,” said Dr. Martin Sanda of Harvard Medical School, who worked on the study.
Welch said the right answer is not clear but added that men should be fully informed about the risks of PSA testing.
“People have to weigh the small chance of a big benefit against the rather larger chance of a harm — and that harm being told you have cancer unnecessarily and treating it unnecessarily,” he said.
According to Dr. Robert O. Young, Director of Research at the pH Miracle Living Center, “using the live and dried blood microscopy with PSA testing and the Gleason score are the best combination of tests for preventing and reversing prostate cancer. Prostate cancer has been 100% reversible when detected early with an alkaline lifestyle and diet. When you reduce the metabolic acid load on the tissues, including the bladder and prostate you can reverse this condition in a matter of a few weeks with no surgery, no hormones, no radiation and no chemo.”