If caught early enough, prostate cancer can be cured in the 1 in 6 to 1 in 10 men who get it. But just as mammography for breast cancer in women has come under fire recently, so has the key test that urologists have been relying on to help detect prostate cancer.
Known as the PSA, the simple blood test for the prostate-specific antigen remains the single most effective means of detecting early prostate cancer, according to a leading authority on the subject, Dr. Jeffrey M. Ignatoff, a specialist in urological oncology at Evanston Hospital and an associate professor of urology at Northwestern University Medical School.
“It is commonly known that PSA testing has flaws, but it’s still the best [test] we have. We [oncologists] know we’re finding earlier prostate cancer, and we have the anecdotal evidence to prove it.
“We don’t have solid evidence that we’re prolonging survival by treating the prostate cancer we find,” he added. “That’s awaiting the results of the PIVOT study, a combined study of the Veterans Administration and the National Cancer Institute, whereby thousands of men with prostate cancer are being randomized; some are being treated and others are being observed to determine if treating prostate cancer extends their lives.”
Nevertheless, according to Ignatoff, even with all its problems, the PSA is still the most “sensitive test for early detection of prostate cancer,” and he believes early detection saves lives.
It was first administered at Maywood’s Loyola University Medical Center, one of five hospitals in the nation involved in experimentation for FDA licensing.
Despite the fact that this test has been available commercially since 1987, most men over 45 in this country are not bothering to be tested for prostate cancer because they are afraid, said Dr. Robert Flanigan, professor and chairman of the urology department at Loyola University Medical Center. And perhaps there is reason for such fear.
When Loyola was involved in obtaining FDA licensing, it screened 6,000 men with PSA tests for cancer and discovered that elevated PSAs, even with negative rectal exams, detected prostate cancer for 1 in 4 men.
The PSA measures the protein manufactured in the prostate gland to produce seminal fluid. An elevation of this antigen in the blood sometimes denotes cancer. For men under 50, the PSA number should be less than 4; for men 60-69, 4.5.; and for men over 70, lower than 6.5.
Some urologists are contemplating a standard of 2.5 for younger men.
Test scores can vary radically
But PSA numbers can vary radically for a variety of reasons, according to Ignatoff.
“I saw one man with a reading of 90 [86 points out of range] who merely had a benignly enlarged prostate, a condition known as BPH. And I found a man with a reading .8 who had cancer.”
So how reliable is such a test when several conditions from BPH to a urinary-tract infection can cause the number to jump?
The PSA test is used as a warning flag, not necessarily as a cancer diagnosis, Ignatoff said.
“A PSA test is just one of two components for the detection of early prostate cancer, and one without the other can be meaningless. The digital rectal exam, which should be used with the PSA, detects a large percentage of tumors I find,” Ignatoff said. It’s still possible to have a normal PSA and have prostate cancer.
Mark N. had always had PSA scores within the norm until age 59, when he was jolted with a score of 11.9. “I was frightened out of my mind, and the first thing I said to my internist was, ‘I have cancer,’ ” he recalled, noting that he went immediately to his urologist.
Despite his high PSA, a rectal exam did not indicate any nodules.
It was believed Mark had an enlarged prostate. Nevertheless, biopsies were taken.
When the biopsies proved negative, he was put on an antibiotic (Cipro) to clear up a prostate infection that had developed from the enlarged prostate. In a month his PSA went down to 3.3.
“I was scared to death for three days while I waited for the report,” he said. “When he [the doctor] said, `I have some good news for you,’ I could finally breathe.”
Urologists agree that even more important than the initial PSA number itself are consistent increases in the number, which would be a cause for concern and further exploration.
Doubts about the test
A study published in the January issue of the Journal of Urology raised questions about the PSA.
Dr. John McNeal, a Stanford University pathologist who co-authored the paper, told the HealthScout News Service, “We used to think [the test] was good, but what we would like it to tell us is whether a PSA that is not much elevated is elevated because of [normal prostate growth] or whether it’s elevated because of prostate cancer.” Right now the test can’t signal those distinctions.
Nevertheless, Dr. Peter Albertsen, chief of urology at the University of Connecticut in Farmington, told the news service that the study “is not going to knock PSA screening off the map by any means.”
Like Ignatoff, Albertsen supports the test. “I think there’s enough tantalizing evidence to think” that routine PSA screening saves lives but not enough to be sure.
One of the biggest flaws in PSA testing is the number of false positives that result in invasive and uncomfortable biopsies. Nevertheless, according to Ignatoff, with all the false positives, the PSA detects early prostate cancer in an extraordinarily higher percentage of patients than ever before. At one time, prostate cancers were not found until after they had spread and the condition had become life-threatening.
“Before that [PSA], all we had in the way of a blood test was prostatic acid phosphatase, which [primarily] determined staging of cancer, usually in the later stages. It didn’t correlate early prostate cancer the way PSA does,” Ignatoff said.
Ultimately, Ignatoff said, the test allows men to catch cancer sufficiently early to allow many treatment options. “If caught early enough prostate cancer is curable.”
Quick review of prostate cancer
What is PSA? It is a simple blood test for prostate-specific antigen, a component of seminal fluid, which if found in excess can signal prostatitis (an infection), enlarged prostate (BPH) or cancer.
What about the “1 out of 2” prostate cancer statistics from European autopsies? A third of all men older than 50 and half of all men older than 70 do have prostate cancer, but generally it is of no clinical significance. It is at the cellular level and is not measurable with PSA nor is it life-threatening.
What are the early symptoms of prostate cancer? None.
Who needs to be tested? All African-American men over 40 or men over 40 who have a family history of the disease should have a PSA test annually with a rectal exam. Otherwise, men over 50.
— M.N.
Sources: National Cancer Institute and Dr. Jeffrey M. Ignatoff.
