Faculty Profiles

Yuanli Liu
Heather Nelson
Stephen Buka
Barbara Burleigh
Eric Rimm
Karen Kuntz

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In a victory against colorectal cancer, the number two cause of cancer-related deaths in the U.S., mortality rates are declining--but no one knows why. Could it be that Americans are heeding doctors' exhortations to quit smoking, eat less red meat, and take vitamins, including folate, as well as an aspirin a day? Are more people over age 50 getting screened? Or are treatments simply getting better? To untangle the overlapping factors that might account for colorectal cancer's decreasing toll, Karen Kuntz is building a mathematical simulation of the disease. The populations she studies are virtual, modeled on normal citizens and actual patients who represent America in cross-section.

At 44, Kuntz is a world leader in the field known as health decision science. Experts of her ilk, typically strong in economics, psychology, or biostatistics, harness computers' astonishing computational power to replicate and analyze a health threat--a type of cancer, say. By feeding everything that is known about the condition into their calculations, they can alter a single variable and estimate its impact in terms of outcome, lives saved and lost, cost, and even quality of life.

Of course, disease simulations are useful only insofar as they mirror reality. Colleagues say Kuntz, trained as a biostatistician, is deft at calibrating her models against large databases of information about real people. She has factored in, for example, statistics concerning colorectal cancers and their precursors, adenomatous polyps, discovered during autopsies or collected over time through surveys like the Nurses' Health Study, which has 122,000 participants.

Two special talents help account for Kuntz's recent naming as president-elect of the Society for Medical Decision Making. First, by toggling back and forth between her computer models and real-life data, she creates tools useful for making decisions regarding prevention, screening, and treatment. Her early work, for example, clarified the role of angiograms and other noninvasive tests for diagnosing blocked arteries in patients with chest pain. Second, Kuntz designs models to make inferences about how diseases progress. There is no ethical way to observe, in patients, the gradual progression of colorectal polyps into cancers. But Kuntz's model can infer the rate of this change.

Kuntz's interest in colorectal cancer began with an assessment of the cost-effectiveness of screening tests for the disease. There are now five recommended strategies involving a variety of tests--the fecal occult blood test; sigmoidoscopy; the double-contrast barium enema; a radiologic exam; and colonoscopy. On the basis of her and others' work, the U.S. Preventive Services Task Force recently concluded that while screening is certainly cost-effective, research does not yet point to an optimal strategy. At a workshop sponsored by the Institute of Medicine in January, Kuntz's team and collaborating groups from four other institutions each reanalyzed their models using a common set of assumptions. "We were pleasantly surprised to find that all five models reached essentially the same conclusion," Kuntz reports. As better data becomes available, particularly on test costs and screening participation rates, Kuntz and her fellow modelers will be able to help shape screening policies and practices.

That's no mean aspiration for someone who spent her 20s casting about for a niche that "spoke" to her. After a six-year stint as a lab tech, Kuntz was looking at graduate schools when she came across the catalog description of a program led by Milton Weinstein, who helped found the health-decision-science field in the 1970s at HSPH. "Now, this makes sense," Kuntz remembers thinking. "Take a quantitative, rational approach to real-life decision making about health."

Today, Weinstein attests, Kuntz is the go-to person, the "Pied Piper," for masters and doctoral candidates at HSPH, as well as for physicians at Harvard's medical school and affiliated teaching hospitals and institutes. All are eager to enlist her expertise in modeling a host of diseases, from breast, lung, cervical, and prostate cancers to asthma and coronary artery disease.
"Karen is extraordinarily generous with her time, which is reflected in the enormous number of publications that cite her as a co-author," Weinstein says. "She's marvelous when it comes to forging collaborations."

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Photo: Kent Dayton