The face of cancer is changing. Last week, the American Cancer Society announced that prostate cancer is now the most frequently diagnosed cancer in the United States, capturing that distinction from breast cancer.
The organization predicts that 200,000 new cases of prostate cancer will be identified in 1994, about 18,000 more than breast cancer and about double the number of prostate cases identified in 1980.
Is this an epidemic?
Hardly. American men aren't any more likely to get prostate cancer than before. Simple demographics tell part of the story: Prostate cancer is primarily a disease of older men, and the population is aging.
"The age at which we are seeing the principal increase is in the older age group, men 70 to 75 years and above," says Dr. Harmon Eyre, chief medical officer for the American Cancer Society. "There is a small, rising increase in all age groups, but the very rapid rise is in older men."
Also, public education about the disease seems to be working. More men are getting screened now, and doctors are detecting more tumors than ever. Some are potential killers, fast-growing tumors that are sure to spread to other parts of the body. Some are small and slow-growing, the type that may never pose a threat.
"In half of all men over 80, you can find incidental prostate cancer at autopsy," says Jonathan I. Epstein, associate professor of pathology and urology at the Johns Hopkins School of Medicine. These are men who died of heart attack, stroke and other causes -- never knowing they had prostate cancer.
With so many cases being diagnosed, some experts fear that patients with harmless tumors are needlessly subjected to radical surgery, in which the patient is put to sleep and his prostate is removed.
This has generated a vigorous debate in medical circles. Just when should a man with early-stage prostate cancer undergo surgery, and when should he simply be monitored?
A recent study by Dr. Gerald Chodak of the University of Chicago found that men with early-stage prostate cancer who receive no treatment have an excellent chance of still being alive after 10 years, almost as good as those who undergo surgery or radiation.
Writing in last week's Journal of the American Medical Association, Dr. Epstein and colleagues at Hopkins presented guidelines they believe will help solve the dilemma for many men with early prostate cancer. The system addresses the most perplexing cancers of all -- "nonpalpable" ones, or those that are too small for a doctor to feel during a rectal exam.
Increasingly, such cases are diagnosed because of the popularity of a simple blood test -- called PSA after "prostate specific antigen." This is a chemical which the prostate gland releases into the bloodstream. Doctors become concerned when man's PSA level becomes elevated, a signal that the prostate has become diseased.
Trouble is, PSA concentrations can rise because of a non-cancerous condition in which the prostate becomes enlarged and interferes with urination. Elevated PSA also can be caused by a cancerous tumor that is growing too slowly to pose much danger.
Or it can flag a deadly cancer.
Doctors use a combination of PSA, ultrasound testing, biopsies and rectal examination to gauge a man's risk. It's not an exact science.
The Hopkins team studied 157 men who had their prostates surgically removed. Most were diagnosed with prostate cancer by outside doctors who referred them to Hopkins for surgery.
The Hopkins team found that 84 percent of the men really needed to have their prostates removed. The tumors were large enough or the cancers aggressive enough to spread to other parts of the body and endanger the men's lives.
In another 16 percent of the cases, the tumors were small enough to qualify for "watchful waiting," a strategy in which the condition is monitored semi-annually to see if it progresses to the stage where surgery is warranted.
The Hopkins team recommended these guidelines for predicting when surgery can be safely delayed:
* Doctors should calculate PSA density -- a measure of how much antigen is being produced compared with the prostate gland's size. This is determined by dividing the PSA level by the prostate size, which is assessed by ultrasound.
* A patient with low densities may qualify for "watchful waiting." To make sure, he should undergo a biopsy.
* Typically, six or eight samples are withdrawn. If no more than two contain cancerous cells, surgery can probably be delayed. Dr. Epstein says doctors also would like to see that the cancer cells closely resemble normal prostate cells, a sign that they are probably slow-growing.
Age is a factor
Another factor is the man's age. The older the patient, the more likely he will die of other causes before his cancer catches up with him.
"Men in their upper 60s who have insignificant prostate cancer are good candidates for watchful waiting," says Dr. Patrick C. Walsh, a Hopkins urologist who also took part in the study. Dr. Marne Carmichael and Dr. Charles Brendler also authored the study.
Men in their 50s and early 60s -- especially those in good health -- may choose to have surgery because the cancer stands a good chance of spreading within the man's expected life span.
"In general, with the younger patient, most clinicians feel it is better to go on the side of overtreating a few than undertreating and running the risk of letting the cancer escape," Dr. Epstein says.
A patient who chooses "watchful waiting" should have his PSA level measured every six months, and a follow-up biopsy at least one year after the initial one, Dr. Epstein says. This would allow his doctor to determine if the condition has changed for the worse.
Outside Hopkins, the guidelines seem to have been received well. Some doctors say they offer a systematic approach toward evaluating slow-growing tumors and reflect a growing consensus about when to treat and when to watch and wait.
"The large majority of patients whose cancers are picked up by PSA only do have significant cancers," says Dr. Michael Naslund, director of the Maryland Prostate Center at the University of Maryland Medical Center.
"It's a minority who really have low-grade cancer, and most of these men are very reasonable to follow rather than treat."
He agreed that overall health -- not just chronological age -- is often the swing factor.
"You look at his medical history: Does he smoke? Does he exercise? Is he overweight? It's a clinical judgment."