Prostate cancer survival rate

The controversy over the prostate-specific antigen blood test for early prostate cancer has erupted again now that the U.S. death rate from this disease has dropped for the first time in decades. For white men, the mortality fell 16% in the 1990s; for black men, the rate declined almost 11% (Epidemiology, 3/00). Since these mortality reductions coincide with the increased use of the PSA test, its proponents have declared victory. They are also encouraged by a yet-to-be-published study conducted in the state of Tirol in Austria, which showed an even more dramatic mortality reduction. After free PSA screenings were offered, beginning in 1993, the prostate-cancer death rate in the Tirol plunged 42%. The new statistics have turned some skeptics into believers, but the issue isn't likely to be settled in the near future. Determining the cause of a drop in mortality from any form of cancer is difficult because there are invariably competing explanations.

More Harm Than Good?

The main arguments against screening for prostate cancer has been the very real possibility that testing symptomless men could cause more harm than good. The treatments, even of early-stage disease, are associated with death and severe complications, such as impotence and urinary incontinence. These risks must be weighed against any possible benefit of prolonged survival. The overwhelming majority of men with prostate cancer have a slow-growing form of the disease; and all but a minority (10-15%) will die of other causes. Even if there were a test that could accurately identify the aggressive prostate cancers, there has been no evidence that early detection is life-saving.

The now widespread use of the PSA test is largely driven by the nation's mortality statistics (and the pharmaceutical industry, see HealthFacts, 7/93). Men are told that prostate cancer is the second most common cause of cancer deaths in the U.S. (39,000 annually); and therefore they should be screened regularly. Half of the prostate cancer deaths in the U.S. are among men over the age of 67 years, but as they reach advanced age, men with prostate cancer often have other serious medical conditions that are more likely to kill them. This has prompted some researchers to suspect that many of these deaths are inaccurately attributed to prostate cancer.

Craig J. Newschaffer, MD, and colleagues at several medical centers, assessed the distribution of death in a large number of men over age 67 with prostate cancer and compared it with that of an equal number of elderly men without the disease (Journal of the National Cancer Institute, 4/19/00). They found that there is a tendency among doctors to attribute the cause of death to prostate cancer in men who had been diagnosed with this disease. A majority (61%) of the so-called prostate cancer deaths were actually due to other medical conditions.

In an editorial that accompanied this study, Peter Albertson, MD, University of Connecticut Health Center, Farmington, cited a similar study he conducted in which 10%-20% of the prostate cancer deaths had been misattributed. Accurate identification is important, he explained, because a decline in the nation's rate of deaths from prostate cancer could mistakenly validate PSA testing and aggressive treatment.

One prominent PSA skeptic who now describes himself as a believer is Otis Brawley, MD, co-author of the new study that tracked the drop in U.S. prostate cancer deaths. Asked to comment on the possible misattribution of prostate cancer deaths, Dr. Brawley, who is the director of the National Cancer Institute's Office of Special Populations, responded, "We have been worried about attribution bias, and my suspicion is that there is some; but the decline [in prostate cancer deaths] is at least partially due to screening and more effective treatmentboth of localized disease and locally advanced disease."

Before PSA screening became popular, Dr. Brawley explained, the man with early prostate cancer typically was a man whose disease was found incidentally during surgery for an enlarged prostate. "In 1980, we'd tell these men that there was no advantage to treating them early with hormone therapy, so we'll watch 'til symptoms occur -- maybe five or six years down the road -- and then give hormone therapy."

Starting in 1989, treatment of early-stage cancer changed, according to Dr. Brawley, and men would be given hormone therapy immediately after surgery, typically with the injectable drug leuprolide (Lupron) or goserelin (Zoladex) which suppresses androgen production. Following radical prostatectomy, immediate anti-androgen therapy was recently shown to improve survival and reduce the risk of recurrence after seven years of follow-up (The New England Journal of Medicine,12/9/99). The same therapy is now given to men whose disease has advanced just beyond the prostate.

"These treatments became common," observed Dr. Brawley, "just as PSA screening became common." Dr. Brawley believes that the Tirol study was even more striking than his own because in this one Austrian state, in one year, doctors first began offering PSA screening and treating with radical prostatectomy and early hormone therapy. These are entirely different practices not only from the rest of Europe but also the rest of Austria, explained Dr. Brawley, where treatment is delayed until symptoms develop. The prostate cancer death rate has dropped dramatically only in Tirol.

Dr. Brawley continues to be concerned about treatment risks. "It's hard to quantify the total amount of suffering," he said, referring to complications like impotence and incontinence. "We stopped screening for lung cancer and neuroblastoma because we found that we were causing more harm than good." The arguments against PSA screening remain. We will still be identifying men who won't benefit from early detection, he explained. "When we used to delay therapy, guys would die of something else. Furthermore, hormone therapy, which is life-long, causes a lot of osteoporosis -- I just saw a guy with hip replacement [as a result]."

"PSA screening can only be a benefit, if adequate treatment is available," warned Dr. Brawley who believes that men must be fully informed of the pros and cons before making the decision to be tested. "A man should consider his fear of prostate cancer in relation to his overall health," he said, "Just last week I was standing in the parking lot of the NIH [National Institutes of Health] and a guy who was blowing his cigarette smoke in my face asked me if he should have a PSA."