he information provided by advocacy groups is blunt.

Y-Me states that breast cancer is "the overall leading cause of death in women between the ages of 40 and 55." It adds: "In the United States, 1 in 8 women will develop breast cancer in her lifetime. This year, breast cancer will be newly diagnosed every three minutes and a woman will die of breast cancer every 13 minutes."

CapCure, the organization founded by Michael Milken to fight prostate cancer, states similar statistics: "In 2002, an estimated 189,000 men will be diagnosed with prostate cancer. This represents one new case every three minutes."

While the figures are accurate, some medical researchers are concerned by the messages they convey. Such statements, they say, may lead people to exaggerate their chances of getting and dying from a fearsome disease.

In an effort to provide another way to look at cancer and other disease risks, three investigators published charts in the June 5 issue of The Journal of the National Cancer Institute, showing how cancer compares with other causes of death at various ages. The result, medical investigators say, shows how the same numbers presented in different ways can have very different emotional tones and gives a glimpse at the slippery nature of human perceptions of risk.

Most statements on cancer risk "are given in isolation, without context," said the lead author of the new paper, Dr. Steven Woloshin of the Veterans Affairs Outcomes Group in White River Junction, Vt. "Without seeing how they compare to other risks, it is hard to gauge what they mean," he added.

Such cancer messages can be misleading, said Dr. Suzanne Fletcher, a professor of ambulatory care at Harvard Medical School. Although cancer is primarily a disease of the elderly, the messages usually do not talk about age and often state the risk over a lifetime. What, women may ask, does this say about my chances of getting a disease?

Working with Dr. Lisa M. Schwartz of the Veterans Affairs group and Dr. H. Gilbert Welch of Dartmouth Medical School, Dr. Woloshin decided to make the abstract risk estimates as concrete as possible. Instead of giving risk over a lifetime, the investigators gave risks over the next decade, a period that is easier to envision.

Instead of giving risks in terms of percentages, they put the risks in terms of individual men and women. For example, data indicate that a 60-year-old woman who smokes has a 4.5 percent chance of dying of a heart attack in the next decade, a 6.5 percent chance of dying of lung cancer and a seven-tenths of 1 percent chance of dying of breast cancer. But the chart gives the same data another way: for every 1,000 60-year-old women who are smokers, 45 will die of heart attacks, 65 of lung cancer, and 7 of breast cancer in the next 10 years.

Dr. Paul Slovic, a psychology professor at the University of Oregon and the president of Decision Research, a private nonprofit organization in Eugene, applauded the effort, noting that it was notoriously difficult to convey risks for a variety of reasons. One is that people want to understand what a particular risk estimate means to them. They tend to discount a risk described as a fraction of a percent and react very differently when the same risk is described in terms of individual people.

"I don't think our brains have evolved to think about risk statistically," Dr. Slovic said. "One of the first things we think about is, Well, is this relevant to me?"

So while 7 of 1,000 is the same as 0.7 percent, people perceive that 7 out of 1,000 is a higher risk. "Even if it is 1 out of 1,000, people think, There is an individual out there dying," Dr. Slovic said. "You can relate to that."

Even harder to understand is relative risk, medical experts said. Dr. Ann Partridge, a medical oncologist at the Dana-Farber Cancer Institute in Boston, said doctors often used the language of relative risk, leading patients to overestimate the benefits of therapy.

"A lot of times, when doctors explain the benefits of chemotherapy, they will say something like, `it will give you a 30 percent decrease in the risk of recurrence,' " Dr. Partridge said. "But in some women, the risk of a recurrence may only be 20 percent," if they have no further treatment, she added. And so, she said, for those women, a 30 percent decrease in a risk of 20 percent really means that the risk reduction is 6 percent.

But risk is a murky concept, Dr. Slovic and others said, and risk perception reveals a constant interplay between reason and emotions.

On the emotional side, people will worry about a disease if they know someone who suffered from it. They will worry if they think a disease can be caused by toxins or chemicals in food, water, or air or by bioterrorists. These worries are "the dread factor," Dr. Slovic said, and cannot be argued away by statistics.

Studies of people who had brain damage that blocked their ability to attach feelings to their decision making showed that their lives were difficult and their decision making abilities fell apart. "Feelings without reasoning can be very problematic and so can reasoning without feelings," Dr. Slovic said.

Yet even within the reasoning side, there are complications that have nothing to do with statistics, medical experts said. Instead, they said, the question is how data on risk for a large group translate into risk for an individual.

"The bottom line, if there is a bottom line, is that risk in an individual case is not an easily defined concept," said Dr. Steven N. Goodman, an epidemiologist at Johns Hopkins School of Medicine.

One way to think about risk, Dr. Goodman said, is that "each of us has a little ticking time bomb, a riskometer inside of us." It says that everyone is at risk and that eating and health habits can raise or lower risk.

"The other way comes closer to the way many people experience risk," Dr. Goodman said. "It says that the risk is not in them but that each individual has a fate. I am either going to live or die at the end of the day. I am going to survive this cancer or not. Probabilities are uncertainties that the doctor has about what is going to happen to us." And that, Dr. Goodman said, "is a profoundly different way of thinking about risk."

The complication, he added, "is that probability has both of these meanings simultaneously."

"Risk in many ways is a state of mind," Dr. Goodman said.

And a change in the way risk estimates are presented can have a profound effect on how fearful people are, he said.

That happened with the new cancer risk charts. Dr. David McNamee, an editor at The Lancet, a British medical journal, sent an e-mail message to Dr. Woloshin saying the charts "work for me."

"Foolishly, I started smoking again last year after quitting for about 20 years," Dr. McNamee wrote. "I can see it is time to stop again (I am 50 in November), and get back to the gym. I have put the charts on the office wall."