At one time, it might have been considered political suicide to admit a diagnosis of cancer -- particularly prostate cancer, the one that no man talked about. But Sen. Robert Dole didn't see it that way when he got the "bad news" last December.

"An option you had was to go into the hospital and sort of hide out for a couple of weeks, which is pretty hard to do anyway, and it didn't seem to me something that shouldn't be talked about," he said recently, sitting before a robust fire in his Senate minority leader's office.

"Plus if someone else knows about it, they might avoid it. Early detection is very important."

Cancer of the prostate gland in the past two years has become the most common cancer diagnosed in American men and the second biggest cancer killer of males behind lung cancer. About 38,000 die of prostate cancer in the United States each year. Live long enough, the experts say, and a man will surely get the generally slow-growing cancer. While prostate cancer is extremely rare in the under-50 group, studies based on autopsies of men who died from other causes have found that it occurs in 30 percent of men over the age of 50 and in 67 percent of those between 80 and 89, whether they knew it or not. It will be diagnosed in one in 11 men during their lifetime.

But like breast cancer in another time, this very common disease has largely gone unmentioned by those whose lives are stunned by it. There has been no public figure to parallel former first lady Betty Ford, whose startling disclosure in 1974 of her breast cancer encouraged thousands of women to seek testing. Now Dole, a Republican from Kansas, is assuming that mantle in his straightforward style, urging men to seek an exam from their physicians and get a controversial blood test to screen them for prostate cancer.

It is an effort that finds Dole at odds with the National Cancer Institute. It has also put him on the forefront of men's health issues for the public.

Since Dole, 68, had surgery to remove his prostate gland last December and appeared last month on two national television programs to discuss the disease, his Senate office has received hundreds of phone calls and letters from men newly diagnosed with the same cancer who said they had gone for testing only after hearing the senator's experience. Dole said his office has even fielded calls from women asking if they could get it. "So there's a lot of ignorance, misinformation, lack of information," he said. Turning Point

In the austere Capitol, where marble busts and oil portraits of older men line the halls, Dole is certainly not alone in his medical situation. Senators Alan Cranston of California, 77, and Ted Stevens of Alaska, 68, were treated for prostate cancer last year, and each sent letters afterward to their male colleagues urging them to be tested.

Chief Justice John Paul Stevens, 71, was treated for prostate cancer last month. The late Sen. Spark M. Matsunaga of Hawaii and the late Rep. Sylvio Conte of Massachusetts died of the disease. Another public figure recently treated for prostate cancer is Steven J. Ross, chairman and co-chief executive of Time Warner Inc. In the Congress, these experiences have fanned bipartisan interest in legislation that would make early detection programs more widespread.

By speaking without inhibition, Dole and other members of Congress are contributing to a turning point in the social history of this malignancy. As with breast cancer, prostate cancer is an extremely common disease of the reproductive system that until recently was difficult to detect in the early stages. Now, urologists cite statistics showing that if the cancer is still confined to the prostate gland at the time of treatment, the patient is curable; 75 percent will live for at least five years. But if the cancer has spread to other organs, there is no cure. Currently, some two thirds of prostate cancers have spread beyond the gland at the time of detection.

Surgery to remove the prostate gland, the most common treatment, carries its own risks and can have the kind of devastating impact on a man's self-image that mastectomy has on a woman's view of herself.

The prostate gland, a walnut-shaped organ, surrounds the urethra in men. It produces secretions that form part of the seminal fluid during ejaculation. A man who has a radical prostatectomy -- removal of the entire gland -- is rendered sterile. Some men may be able to have an erection and orgasm, but no ejaculate will come out. In addition, the operation can sometimes damage nerves in the genital region, causing impotence and urinary incontinence. Thus, prostate cancer treatment can have emotionally difficult consequences.

"Because it affects men's sexuality after the surgery," Stevens explained, "it affects the willingness of men to talk about it, even to other men. I believe two or three other men in Congress have had this surgery and never told anyone outside their families."

In the past, fears of the effects of both prostate cancer and its treatment have inhibited men from inquiring about the disease and paying attention to symptoms. But recent advances in diagnosis and surgery may help dampen fears and move the disease into an arena of public discussion.

Today, with vastly improved surgical techniques that spare crucial nerves, the operation to treat prostate cancer leads to impotence and incontinence in fewer than 5 percent of cases. In addition, radiation has been found effective for early stage cancer.

There is also a new blood test that aids in detecting early, curable prostate cancer. It was this new test that led to a diagnosis of cancer in Dole. Called the prostate specific antigen (PSA) test, it measures the amount of this tell-tale protein produced by prostate cells. But while an elevated level of PSA signals a problem in the prostate gland, it may not necessarily be cancer. An enlarged prostate gland, an infection or a benign tumor can also cause PSA levels to go up. The test was introduced in 1986 and is approved by the Food and Drug Administration only for monitoring remission in men who have already been treated for prostate cancer.

Nonetheless, physicians throughout the country are routinely using the test to help make an initial diagnosis of cancer even though it is not approved as a diagnostic tool.

Dole said his prostate problem came to light in the course of an annual physical with the attending physician to Congress, Robert C.J. Krasner, who performed a routine digital rectal exam and felt an enlarged prostate. Prior to that, said Dole, he had been experiencing frequent urination at night. This is a hallmark symptom of prostate problems because an enlarged prostate can constrict the urethra, preventing the bladder from emptying completely.

Krasner followed up with a series of PSA tests over the next few months. The first turned up a level of 4.8 nanograms per milliliter, considered elevated, but Krasner explained to Dole that cancer might not necessarily be the culprit. Subsequent tests, however, saw the PSA level rising to 6.9, 8 and then back down to a little over 7. A rising level of PSA can signify an increase in the volume of a suspected tumor, researchers say. Dole then underwent a biopsy of the prostate gland that revealed cancerous tissue. Dole's prostate was removed Dec. 18 by Col. David G. McLeod, a surgeon at Walter Reed Army Medical Center. The senator was back at work two weeks later, a convert to the usefulness of the PSA test in early detection of prostate cancer.

Although the PSA test "gets mixed reviews," Dole said, because it does not specifically diagnose cancer and requires some sophistication in its interpretation, "it's another tool. It seems to me it ought to be used. It's like an early warning test." Opposing Viewpoints

Dole was eager to get Medicare to pay for the PSA test, as it does for mammograms, so that older men most at risk of prostate cancer would have this avenue to early detection. Two weeks ago, before launching a bill, he called in a group of experts on PSA, including representatives from the National Cancer Institute, the FDA and Johns Hopkins Medical Institutions. What he found was a brisk argument between the NCI and urologists over whether the PSA test is effective as a screening tool for prostate cancer -- and whether the test ultimately saves lives.

"We thought about Medicare screening," said Dole. "Then, we got this big lecture from the NCI up here on why it wasn't a good idea."

The cancer institute is planning to launch a 16-year study to determine the effectiveness of the PSA test. "Well, by that time, half a million men will be dead," Dole continued. "They're talking about cost, and they have a lot of good reasons not to do it. My view is, how are you going to alert people?"

If the PSA test is only used to monitor a recurrence in men who have already been treated for prostate cancer, said Dole, it's "after the horse is out of the barn."

The NCI argued strenuously that there is no scientific data proving that the PSA test affects long-term survival statistics. For that reason, it should not yet be used as a screening test on the general population, NCI officials said.

What's more, catching prostate cancer in its earliest stages in many people may actually be potentially harmful, explained Barnett Kramer, associate director for the Early Detection and Community Oncology Program at NCI. That's because many prostate cancers are very slow growing. "Autopsy studies show many more men die with prostate cancer than die of prostate cancer," he said. The PSA test may pick up microscopic cancers that never would have become life-threatening in a man's lifetime, yet a man might risk radical prostate surgery that, like any major surgery, carries a small risk of death from the operation itself or may cause permanent impotence, incontinence and rectal damage, he said.

Prostate cancer, the experts agree, presents some conundrums. Though extremely common, almost inevitable in the aged, it may not need to be treated in everyone who has it. It may be that very tiny cancers, left untreated, would likely not kill the patient anyway. He would die of something else first. Doctors, for example, usually do not recommend surgery for men beyond the age of 75, or those who have limited life spans for other health reasons.

At the same time, doctors want to find a cancer before it has spread. If caught early, while still confined to the gland, the cancer is highly curable. This argues for a more aggressive approach to detecting and treating early prostate cancer. To most cancer specialists, any tissue that is malignant and growing should be removed.

As a cancer tool, the PSA test poses its own dilemmas. Health officials estimate that the test misses about 20 percent of the cancer. On the other side of the coin, the test could indicate a major problem when there isn't one.

Last April in the New England Journal of Medicine, William J. Catalona at Washington University School of Medicine in St. Louis presented the strongest published data to date on the usefulness of the PSA test. He compared a group of men who received only a rectal exam and follow-up biopsy to men who had a high PSA level found and subsequent rectal and ultrasound exams followed by biopsies. The comparison revealed that the PSA test used in conjunction with a rectal exam or an ultrasound exam picked up a significant number of cancers that would have been missed had either a rectal exam or ultrasound been used alone. His conclusion: The combination of the three detection methods "provides a better method of detecting prostate cancer than rectal examination alone."

"The real question is, will early diagnosis mean improved survival rates?" said R. Joseph Babaian, professor of urology at M.D. Anderson Cancer Center in Houston. Since 1987, M.D. Anderson has used the PSA test in conjunction with other prostate exams for early diagnosis of cancer. Babaian cited a precedent in breast cancer patients who, diagnosed early through mammography, "have decreased mortality from breast cancer, and I would expect that prostate cancer, which has a lot of similarities to breast cancer, will follow the same path, but as yet we don't have a scientific answer to that question."

The outlook is complicated by the fact that prostate cancers can grow quite differently, and researchers don't know why. William R. Fair, chief of urology at Memorial Sloan Kettering Cancer Center in New York, who does research into the biology of prostate cancers is trying to identify those tumors that will really behave like cancer and grow rapidly and separate them out from the tumors that will have a benign course. "That's what we really want to know," he said. "Now, we feel compelled to treat all of them as aggressively as we can. If we had a crystal ball or molecular marker to say, 'This is a bad tumor and ought to be treated aggressively' and 'This one is not so bad, it may take 30 years to be a risk to a patient's life,' we'd be in a better position than we are now."

What also exacerbates the current debate is the difference between using the PSA test to make the diagnosis of cancer and using the test to screen men who have no symptoms of prostate disease.

The cost of widespread screening is a major issue. The NCI has estimated that PSA testing and subsequent treatment of all men ages 50 to 70 could cost between $6 billion and $14 billion annually. The PSA test itself can cost between $30 and $85. The test is frequently repeated, then followed with ultrasound examination and biopsies. If a tumor is detected, treatment usually follows with radiation therapy or surgery. Chemotherapy has not been found to work against prostate cancer.

Fair has observed an increase in referrals from internists whose patients have elevated PSA results. "Then the urologists are almost obligated to do a biopsy even though the rectal exam is normal," he said. "What that translates into is that we, the urologic profession, are doing far more biopsies than we ever did before, driven solely by the PSA, and a lot of these biopsies are negative."

In light of these ambiguities, the NCI insists that a large study is necessary to follow men who have been screened with the PSA test and compare them with men who have had routine medical care. After 16 years, researchers will know if mortality rates are affected and if there is a way to distinguish which men benefit from the screening. The test may be more effective in screening people known to have a greater risk of prostate cancer. This disease, for example, is more prevalent in black men than in white men, and in men with a father or brother who has had the cancer.

But if Congress and urologists forge ahead and encourage the PSA test as part of routine medical care, said Kramer, the NCI will effectively lose its control group and will have to drop the study, missing the only chance of finding definitive answers to the questions. Compromise Position

Dole said he is impressed with NCI's arguments against generalized PSA screening now but also found persuasive the view of urologist Patrick Walsh of the Brady Urological Institute at Johns Hopkins. Walsh is the acknowledged national expert in prostate surgery who pioneered the nerve-sparing operation that is now widely used to treat prostate cancer. Walsh said he strongly advocates use of the PSA test.

"There is accumulating evidence that the proper use of PSA can be useful in detecting early, curable prostate cancer," he said. "About 25 percent of men with a PSA between 4 and 10 will have cancer and about 65 percent of men with a PSA over 10 will have cancer, so there's no question that an elevated PSA means something."

For those who say the PSA test will lead to unnecessary treatment for microscopic cancers, Walsh counters that the PSA will most likely pick up only significant cancers. It takes a gram of cancer, he said, to raise the PSA level by 2.5, according to one manufacturer's test. "It's pretty clear that to raise your PSA you have to have quite a bit of cancer there."

He suggests that a man whose rectal exam reveals a nodule have a biopsy, regardless of what his PSA level is. "If a man has an elevated PSA and nothing palpable {upon rectal exam} he should at least undergo an ultrasound examination of his prostate; and there is compelling evidence if the PSA is over 4 he should undergo random biopsies."

At the same time, Walsh agrees that localized prostate cancer in men with an expected life span of less than 10 years should not be aggressively treated with surgery.

Dole's meeting of specialists produced compromise legislation adding the PSA test to ongoing preventive screening studies being run by the Department of Health and Human Services in five states. That legislation has bipartisan support and will be tacked onto whatever tax measure eventually passes this session. But Dole said he is still interested in Medicare funding for widespread use of the PSA test to detect cancer.

"I'm a novice at all this," the Kansan said. "I want to be careful we're doing the right thing. We haven't come to grips with that yet."

The American Cancer Society is in the process of revising its guidelines on screening. Currently, it recommends an annual digital rectal exam for men after age 40, but that exam is primarily intended to pick up rectal cancer, revealing prostate cancer only incidentally. At a meeting next month, the society's Committee on Cancer Prevention and Detection will review the latest data on the PSA test and consider recommending it at periodic intervals for men over 50.

Many cancer specialists are already convinced that the test is an effective screening tool. Said Curtis Mettlin, chairman of the committee and chief of epidemiologic research at Roswell Park Cancer Institute in Buffalo, N.Y.: "On the basis of our own research and the research reported by others, the PSA test has surprising potential."

At this point, it looks like the NCI is fighting a rising tide in favor of the test. According to numerous cancer specialists, epidemiologists and urologists, the PSA test is already in widespread use by family practitioners and urologists as a way to detect problems with the prostate and as an adjunct to the digital rectal exam, despite the FDA's strictures. For example, later this year the M.D. Anderson Cancer Center will launch an early cancer detection program called Texas Outreach that will provide free PSA testing across the state for men between age 50 and 75.

According to urologists, many insurance companies reimburse for the test if it is used as a diagnostic tool to follow up when there is some symptom, such as pain or frequent urination. The two companies manufacturing the PSA test are expected to apply to the FDA for approval to use it in screening.

But whether the test and early detection will affect survivor rates in prostate cancer "is a question no one's going to be able to answer for quite a few years," said Babaian at the M.D. Anderson Cancer Center. "Does that mean we should sit back and do nothing when prostate cancer is the most common cancer affecting American males and is the second most common cause of cancer death in American males?

"If someone asked me, is PSA a screening tool, I'd say no, it's not a proven screening tool. But if someone asked me if I'd get it for my health care, I'd say yes."

Prostatitis (inflammation of the prostate). Usually caused by bacterial infection that may be sexually transmitted. Treated with antibiotics.

Enlargement of the prostate (benign prostatic hypertrophy or BPH). More than half of all men in the U.S. over the age of 50 suffer from BPH, which occurs when the prostate gland swells and pushes against the urethra and the bladder, blocking the flow of urine. Mild symptoms require no treatment. To alleviate severe symptoms, the prostate may be removed or a catheter kept in place to drain urine.

Benign tumors. These are not cancerous, do not spread to other parts of the body and seldom are a threat to life. Often they are removed by surgery and do not return.

Malignant tumors. Cancer that can metastasize (spread) through the bloodstream and the lymphatic system to other parts of the body. Treated with surgery, radiation or hormone therapy. Considered curable if diagnosed while still confined to the prostate gland.

SOURCE: National Cancer Institute

Need to urinate frequently, especially at night.

Difficulty starting urination or holding back urine.

Inability to urinate.

Weak or interrupted flow of urine.

Painful or burning urination.

Blood in the urine.

Painful ejaculation.

Continuing pain in the lower back, hips, or upper thighs.