"Determining health risk is a science. Communicating risk information remains an art," said Barbara Biesecker, a genetics counselor at the National Human Genome Research Institute in Bethesda, Md. People like Biesecker hope that mastering the art of risk communication will translate into improving the publics health.
Thats exactly what the researchers at Harvards School of Public Health are trying to do with their new Web site, http://www.yourcancerrisk.harvard.edu let the public know what lifestyle changes they can make to lower their risk of cancer.
"We estimate that 50% of all cancer can be prevented," said Graham Colditz, M.D., Dr.P.H., at the Harvard School of Public Health in Boston, Mass., and one of scientists who developed the site. "Our risk assessment tool explains to people how their habits affect their risk and offers a road map to show them which changes in their lifestyle will have the biggest impact on their health."
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The site developers decided to limit the Risk Index to cancers that account for about 80% of cancer incidence. These include melanoma and breast, prostate, lung, colon, bladder, uterine, kidney, pancreatic, ovarian, stomach, and cervical cancers. The site works by assigning points to certain genetic, environmental, nutritional, and lifestyle factors, plus major illnesses that are definite or probable causes of cancer. So, as each user answers the multiple-choice questions, he/she accumulates cancer risk points that are then compared to the prevalence of the same risk factors in the general U.S. population.
Two epidemiologists at the University of Pittsburgh, H. Samuel Wieand, Ph.D., and Joseph P. Costantino, Dr.P.H., said the site is very well done and useful overall. They felt, however, that it was important for everyone to read the disclaimer before going into the program. "The user should understand that the index is a crude measure that doesnt directly apply to each individual," said Wieand. "People shouldnt make any major health decisions based only on the Index." As it stands now, the disclaimer can be read by clicking on a side button, but it might not be noticed.
Another point the scientists made was that they thought it was very important to include absolute risk. "A twofold relative risk for a somewhat common cancer is clearly of more concern than a twofold risk for a more rare cancer," said Wieand.
Mitchell Gail, M.D., Ph.D., chief of the biostatistics branch at the National Cancer Institutes Division of Cancer Epidemiology and Genetics, agreed. "A woman with an above average risk of ovarian cancer but a normal risk of breast cancer might get the message that she should worry mostly about ovarian cancer, which is much more rare than breast cancer."
The developers of the Index were also concerned about giving relative risk without absolute risk. "Its an important point because the best evidence for risk communication says you should have both relative and absolute risks," said Colditz.
Part of the problem is the numbers. His colleague, Katherine Emmons, Ph.D., an associate professor of health and social behavior at Harvard School of Public Health, found out in focus groups that many people have difficulty handling even simple addition and subtraction, let alone percentages, or imagining numbers larger than 100. Another part of the problem is that absolute risk depends on the country where they live. (Colditz believes that initially about 10% of Web users were from outside the U.S.)
"We havent resolved how to deal with the international rates. Clearly, its something we want to do. With more money down the road, we will do the work to solve the problem," said Colditz. He also wants to put the cancer risks in perspective, comparing them with heart disease, osteoporosis, diabetes, and other conditions.
NCI scientists, including Gail, considered similar issues when they created the breast cancer risk assessment tool (http://bcra.nci.nih.gov/brc/). They did include absolute risk, but not consistently, said Steven Woloshin, M.D., at the Department of Veterans Affairs Medical Center, in White River Junction, Vt., and Dartmouth Medical School in Hanover, N.H. For example, one of the messages in NCIs breast cancer risk assessment tool was to inform women about the benefit of tamoxifen in preventing breast cancer, which was described in terms of relative risk: "Women [taking tamoxifen] have about 49% fewer diagnoses of invasive breast cancer compared to women who took a placebo." In contrast, one of the risks of taking tamoxifen, developing uterine cancer, was presented using absolute rates: "The annual rate in the tamoxifen arm was 30 cases of uterine cancer per 10,000 women compared to 8 cases per 10,000 in the placebo arm." Woloshin said he thinks that this asymmetric presentation tends to emphasize benefit and minimize harm. A balanced approach would frame benefit and harm information as absolute risks, he said.
Besides presenting data symmetrically, Woloshin and his colleague, Lisa M. Schwartz, M.D., also at Dartmouth and VA Medical & Regional Office in White River Junction, Vt., think it is important to put risks in contextto help the reader or user understand how the chance of developing one disease compares to others. They propose that a federal agency that already collects this information, such as the National Center for Health Statistics, be responsible for constructing wall charts (for example, see chart below) that provide context for diseases and interventions. These could be available to physicians and the public.
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Another effort at improving the communication of risk information has been created by Peter Ravdin, M.D., Ph.D., at the University of Texas Health Sciences Center in San Antonio. He and his colleagues produced a computer program for early-stage breast cancer patients to help them decide whether to receive adjuvant therapy. The program makes estimates of survival at 10 years of follow-up with and without different treatment options.
Ravdin and his colleagues completed a pilot study and found that, in general, women like the tool because it gave them a sense of control. "What we found is that most women are much too pessimistic about what they think will happen and too optimistic about what drugs will do," said Ravdin.
Now they are beginning a randomized trial together with a team at Case Western Reserve University, Cleveland, led by Laura Siminoff, Ph.D., to test the decision tool with 300 women for 3 years. They are asking women whether or not they understood their situation better, what treatment they ultimately chose, and whether they chose to go into clinical trials. They will also be evaluating physician and patient satisfaction with the process.
Annette OConnor, Ph.D., a professor at the University of Ottawa and clinical epidemiologist at the Loeb Health Research Institute at the Ottawa Hospital in Ottawa, Canada, and her colleague Valerie Fiset, a clinical nurse specialist at the SCO Health Service in Ottawa are working under the premise that understanding the risks and benefits of a treatment or screening option are only part of what goes into decision-making.
The Ottawa decision aids are a series of evidence-based, take-home, self-administered tools to prepare patients to make certain medical decisions, such as stage IV lung cancer patients deciding whether to receive chemotherapy and breast cancer patients deciding whether to have breast conserving surgery or a mastectomy. The unique feature of these aids is that they include a component of values clarificationpeople are encouraged to think through what is most important to them in making decisions.
For example, Fiset said in the lung cancer decision aid the most important value was survival. "But since the survival benefits arent that great," she said, "other issues became important, like inconveniencing family members for rides to and from treatment and being afraid of nausea and vomiting."
The developers of the aids have found that they have the greatest impact among patients who are uncertain about which option to choose and they increase realistic expectations of the outcome. Information about the aids is available through the Loeb Health Research Institutes Web site, http://www.lri.ca/.
These efforts represent a small portion of the intense research activity taking place in the field of risk communication. Risk research shows that most people have difficulty understanding probabilities, and communication efforts are affected by a persons perceived risk, receptivity, and cultural background. Although there seems to be little consensus about the most effective way to communicate, perhaps one day, communicating cancer risk may be more of a science than an art.
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