A Marriage of Math and Medicine: Dr. Harvey Risch on a Career in Cancer Epidemiology
Dr. Harvey Risch
Harvey Risch, MD, PhD, is the chair of the President’s Cancer Panel. Dr. Risch has spent his career conducting research in epidemiology—with a focus on cancer as well as on epidemiologic methods—and teaching epidemiology to graduate and public health students. Currently, he is Professor Emeritus and Senior Research Scientist in Epidemiology at the Yale School of Public Health and Yale School of Medicine.
Throughout his career, says Dr. Risch, “there’s been this tension in my academic thinking, going back and forth between medicine and biology and math and quantitation.” As an undergraduate at Caltech, Dr. Risch was majoring in mathematics when he decided he wanted to do something more human-focused. He added a second major in biology and went on to medical school. After earning his MD, he pivoted back toward math, studying biomathematics at the University of Chicago. His dissertation focused on mathematical modeling of infectious epidemics—and his research interest clicked: “I thought, if I’m going to marry quantitative science with medicine, that’s really in the domain of epidemiology.”
Dr. Risch describes epidemiology as “one of the strangest sciences there is.” He explains that epidemiologists study groups of people from a population as controls and groups of people with a disease to make conclusions about the population and the disease as a whole. Studies must be done very carefully to avoid bias and confounding factors, which can lead to inaccurate conclusions. The field, he says, is essentially applied probability—and probability is often difficult to grasp. However, this strange, nonintuitive field was a perfect fit for someone with interests in both math and medicine.
Dr. Risch further refined his focus after graduate school. At the University of Washington, he began working in cancer epidemiology, and at the University of Toronto, he was immersed in fieldwork. He drew on both of those experiences when he joined Yale, where he was able to take advantage of the Connecticut Tumor Registry. The registry—the oldest one of its kind in the United States—allowed Dr. Risch and his colleagues to quickly identify and contact people who had been diagnosed with cancer, enabling epidemiologic studies.
One of the projects Dr. Risch found most interesting during his career at Yale involved investigating the role of Helicobacter pylori (H. pylori) infection in development of pancreatic cancer. H. pylori is a bacterium that often infects the stomach and is associated with the development of stomach cancer. H. pylori does not infect the pancreas, but researchers had found that H. pylori infection was also linked to pancreatic cancer. To understand why an infection in the stomach might lead to cancer in the pancreas, Dr. Risch went back to what he had learned about the gastrointestinal system and immunology in medical school. Eventually, he developed a theory about the effects of H. pylori on production of stomach acid, which in turn affects the pancreas. With funding from NCI, Dr. Risch was able to investigate H. pylori infection in people with and without pancreatic cancer, and he found the associations he had expected. “I went out on a limb and made this theory,” he says, “and then 7 or 8 years later got results that substantiated the theory. I was very academically fulfilled by that.”
However, although Dr. Risch finds epidemiologic research satisfying, he notes that it is not just an academic exercise. He hopes that his findings—which shed light on how different cancers develop and the role of various risk factors—will help to advance cancer prevention efforts. Although tremendous strides have been made in cancer treatment, he says, “everyone agrees it’s better not to get cancer in the first place.” Ultimately, his marriage of math and medicine aims to make that a reality for more people.