The cancer men don't talk about.

Senators Robert Dole and Jesse Helms have it. So do Supreme Court Justices Harry A. Blackmun and John Paul Stevens. And 132,000 other American men get it each year.

They have the disease men don't talk about--cancer of the prostate. But men should be talking:

* Since 1985, rates have grown by six percent a year.

* It's the most common non-skin cancer among men, accounting for one out of every four men's cancers.

* It kills 100 American men each day. Only lung cancer is deadlier.

Sadly, many of those deaths can be chalked up to embarrassment. If prostate cancer is detected early--using a simple test--the odds of surviving are more than 90 percent. Yet how many men do you know who have a yearly rectal exam?

So can we talk?

The prostate is a walnut-sized gland that straddles the urethra, the tube that drains urine from the bladder through the penis. It produces seminal fluid, which helps transport sperm.

"I was like most men, barely aware I even had one, much less aware it could develop into a life-threatening problem," recalls Bob Dole, whose cancer was diagnosed in 1991.

THE FAT LINK

Eventually, one in 11 men will get prostate cancer. Those on the list:

* Seniors. The older you are, the greater your chances (see graph). More than 80 percent of prostate tumors are diagnosed in men aged 65 or older.

* African-Americans. American blacks have the highest rate of prostate cancer in the world. The culprit might be their slightly higher levels of testosterone, a harmone that stimulates the growth of prostate tumors.

* People with a family history of prostate cancer. A man has a much greater chance of developing prostate cancer if his father or a brother had it, particularly before age 65.

* People who eat diets high in fat (especially animal fat). "Populations that eat larger amounts of fat have strikingly higher rates of prostate cancer," says Curtis Mettlin, chief of epidemiology research at Roswell Park Memorial Institute in Buffalo, New York.

Men in the United States, for example, eat large amounts of animal fat and have high death rates from prostate cancer. Greeks, on the other hand, eat about half as much animal fat as we do and are half as likely to die of prostate cancer.[1]

But it's not nationality that makes the difference. It's environment. Native-born Japanese who leave their country (where prostate cancer death rates are low) and move to Hawaii (where they're high) are three times more likely to die of prostate cancer than those who remain in Japan.[2]

"Differences in diet are the only way to explain why some countries have higher rates of prostate cancer than others," says Ernst Wynder, president of the American Health Foundation.

Studies that compare groups of people who live in the same country but who have different eating habits strengthen the link between fat and prostate cancer.

For example, Seventh-day Adventists who reported consuming the most meat, milk, cheese, and eggs were more than three times as likely to die of prostate cancer over the next 20 years than Seventh-day Adventists who said they ate the least amounts of those foods.[3]

And in Utah, men who recalled eating the most saturated fat were 80 percent more likely to have developed "aggressive" prostate cancer (the kind that spreads and is difficult to cure) than similar men who ate the least saturated fat.[4]

Most studies point to meats and dairy products, but it's impossible to completely exonerate vegetable fats until scientists come up with an animal that develops a similar tumor )a "model"), so that they can compare one fat's effects with another's.

How can fat affect the prostate? Some researchers believe that it raises the levels of testosterone and other hormones, which could stimulate the prostate to grow--along with any cancer cells it may harbor.

So far, researchers haven't found that people who eat diets rich in fruits and vegetables have a lower risk of prostate cancer--a link that exists for lung and colon cancer.

And while scientists have suggested other risk factors (untreated venereal disease or the occupational exposure to cadmium, for example), none have been well-substantiated.

"NURSE, THE GLOVE, PLEASE"

"If prostate cancer is detected while it's confined to the prostate, the odds of surviving are very good--up to 90 percent," says Barry Kramer, associate director of the National Cancer Institute's Early Detection and Community Oncology Program.

But if it has escaped the gland's outer jacket, the survival rate over the next five years falls to about 45 percent. And if it has spread to the lymph nodes, to the bone, or through the bloodstream to other organs, the odds of survival fall to 15 to 20 percent.

The two most common ways to detect a tumor are:

* Digital Rectal exam. Most prostate tumors can be felt by a finger inserted in the rectum. This is the easiest and least expensive way.

It's also the most embarrassing. Less than half of all American men who should be routinely getting a rectal exam do so, according to Gerald P. Murphy, chief medical officer of the American Cancer Society.

"They're just not taking care of themselves by getting their yearly checkups," he says.

* PSA test. An ailing prostate secretes a substance called prostate-specific antigen (PSA). In some cases, a PSA test can reveal the presence of a cancer that the doctor can't feel through a rectal exam.

But high blood levels of PSA are also found in men suffering from prostatitis (an inflammation of the gland) or from benign prostatic hyperplasia, an enlargement of the prostate that afflicts many middle-aged and older men. (The jury is still out on whether an enlarged prostate increases the chances of developing cancer.)

And normal PSA readings could occur even if a cancer were present. That's why the test is most often used along with a rectal exam.

Using the rectal exam, doctors manage to catch about 60 percent of prostate cancers before they spread. Throw in a PSA test and the number jumps to nearly 70 percent, says the Cancer Society's Murphy.

HIDE OR SEEK?

If a cancer is caught early--when it's still confined to the prostate--the standard treatments are surgery (to remove the gland) or radiation.

If it has spread beyond the prostate, then it usually can't be cured.

Instead, its growth can be slowed--and some of the discomfort it causes relieved--by radiation or by cutting the body's production of testosterone, either through drugs or removing the testicles.

"These treatments have their pluses and their minuses," says the National Cancer Institute's Barry Kramer. Radiation or surgery to remove the prostate causes temporary or permanent impotence or incontinence about half the time.

And that's why Kramer and others don't endorse the American Cancer Society's recommendation that all men over 50 get an annual PSA test along with their rectal exam.

"The PSA test may identify many men with small, slow-growing cancers who will then want to be cured with treatments that may be more destructive than the tumors themselves," he says.

Others see no reason to wait, when a man can easily find out if he has prostate cancer. Then he can evaluate his options.

"Better to over-diagnose than under-diagnose," says cancer researcher Curtis Mettlin, "because by the time we find 40 percent of these cancers, it's too late to cure them."

Senator Bob Dole, whose cancer was detected with the PSA test, agrees.

"I'm one of the many men who consider themselves living proof that early detection can mean a healthy future. Please get routine checkups, and don't neglect to have your doctor check for prostate disease. It could save your life."

[1] Cancer 58: 2363, 1986.

[2] J. Nat. Cancer Inst. 40: 43, 1968.

[3] Am. J. Epidemiol. 120: 244, 1984.

[4] Am. J. Clin. Nutr. 52: 752, 1990.