Prostate-cancer death rates among American men dropped decisively over the past 10 years — the decade following introduction of the prostate-specific antigen blood test — according to a new study by researchers at the National Cancer Institute in Bethesda, Md.
Separately, European cancer researchers in a new and still-unpublished report will shortly announce an even steeper plunge in mortality among men who were offered free PSA screening in the Austrian state of Tirol.
It's welcome news by any measure. After lung cancer, prostate cancer is the United States' second-biggest cancer killer, with 180,400 new cases and 31,900 deaths expected this year. But does the new data offer the ringing vindication of PSA that the test's advocates are celebrating?
Skeptics in the scientific community, while no less gratified by the statistics, insist it isn't clear whether the gains in survival are mainly due to screening and early detection, to faster and better treatment, or to a combination of both.
The questions are at the heart of a long-running debate over the merits of PSA screening, which measures levels of antigen, a type of protein, from the prostate. Elevated levels can be caused by cancer. But they can also come from an overgrowth of normal tissue as a man ages — which, PSA skeptics point out, can lead to false positives and trigger the cost and discomfort of needless biopsies.
Another facet of the debate centers on the variability of prostate tumors, with some being aggressive and lethal and others slow and nonthreatening. The prostate, a walnut-shaped gland nestled beneath a man's bladder, produces seminal fluid, and prostate cancer is usually treated with surgery, radiation or hormones to counter the testosterone that fuels the tumor. Skeptics fear that over-reliance on PSA may lead men with nonlethal cancers into unnecessary surgery or radiation with major side effects like impotence and urinary incontinence. Major refinements in surgery and radiation have reduced — but not eliminated — these problems.
As the debate has intensified, many American men have been voting with their feet in favor of getting screening from their family physicians. But untold numbers of others have hesitated out of fear, denial or confusion spawned by conflicting advice from government bodies and medical organizations — a mixed message that is sure to persist even in the wake of the two new studies.
In the U.S. study, cancer-institute researchers tracked long-term declines in the prostate-cancer death rates among men of all ages, both black and white. The death rates now have dipped below the levels of 1986, the year when PSA was first approved.
Among men aged 60 to 79 years old, death rates are even lower than they were in 1950. For whites, mortality fell 16 percent during the 1990s. Among blacks, who are statistically at greater risk, the rate dropped almost 11 percent.
The study by NCI researchers Otis Brawley, Robert Tarone and Kenneth Chu was published in the journal Epidemiology in March.
The unpublished Tirol study data offer even greater improvement in survival statistics. In the study, Peter Boyle of the European Institute of Oncology in Milan, Italy, and Georg Bartsch of the University of Innsbruck, Austria, contrasted prostate-cancer death rates in Austria as a whole with death rates in the state of Tirol, where a program of free mass PSA screening was introduced in 1993.
After two-thirds of the state's 65,000 eligible males aged 45 to 75 underwent PSA screening, the prostate-cancer death rate in Tirol plunged 32 percent below expected levels in 1997 and 42 percent below expected levels in 1998.
Boyle and Bartsch have submitted their study to the British journal Lancet.
The results will be unveiled at the American Urological Association meeting in Atlanta, which gets under way this week.
Currently, the American Urological Association backs "regular" PSA screening. The American Medical Association recommends a PSA test every three years after age 50.
The American Cancer Society, which previously promoted a proactive program urging men to seek annual screenings, retrenched in 1997 to a more moderate stand.
The cancer society now recommends that doctors offer the PSA test and digital rectal exams (to check the prostate's size) to all men annually from age 50, and earlier to men at higher risk, including blacks and those with a family history of the disease.
On the other hand, the government-sponsored U.S. Preventive Services Task Force in its influential "Guide to Clinical Preventive Services," flatly labels the PSA test "not recommended" as a routine test because of doubts about its value. Similarly, the American College of Physicians and the American Academy of Family Physicians don't recommend routine screening but urge doctors to counsel men about the test, mentioning both its benefits and its drawbacks.
Among prominent individuals taking a stance on PSA, one of the most vocal of the pro-screening group is Andrew Grove, the founder of Intel Corp. and a prostate-cancer survivor.
"Yes, I'm glad I was screened," says Grove, who passionately argues that early detection preserves more treatment options for men. "I am forever grateful to my doctor for it. No question, dealing with cancer is not fun. But I prefer that the choices of treatment are left to me, rather than to others in the name of saving me from having to deal with bad news and causing me to inherit worse."
In the meantime, a number of cancer experts are still sitting on the fence.
At a session of the American Association for Cancer Research in 1998, some 3,000 scientists were asked to indicate with a show of hands how many would have PSA screening. About half raised their hands in favor of the test.
"It creates enormous controversy every time it's debated. A straw poll of cancer specialists split 50-50 is a good commentary on the state of the science," says Harmon Eyre, chief medical officer of the American Cancer Society.