Dr. Debra Silverman
Chief, Occupational and Environmental Epidemiology Branch,
When Dr. Debra Silverman caught her first glimpse of cancer research as a high school student in Brooklyn, she says, "It inspired something within me." Her Advanced Placement biology class - a program which was then in its infancy - took a memorable field trip to nearby Memorial Sloan-Kettering Cancer Center. While there, the group visited a lab conducting early animal studies of tumorogenicity of constituents of tobacco smoke.
"Cancer seemed like a great puzzle to me at the time. We understood very little about what caused it. Smoking was very prevalent," she recalls. "Early papers had come out in the 1950s about the connection between smoking and cancer, but the impact of that work hadn't taken effect. I really wanted to do something important in my career, and that trip planted a seed of interest in research that later circumstances allowed to grow."
Dr. Silverman continued to pursue that interest through college and graduate school in biostatistics, culminating with a doctorate in epidemiology at the Harvard School of Public Health, where she was one of the first non-M.D.s to complete the program and among the first women graduates.
Now an internationally recognized expert on bladder cancer, Dr. Silverman has co-authored more than 50 papers on the topic. Her early work provided the first national estimates of the prevalence of occupationally induced bladder cancer. She was also the first to demonstrate that truck drivers have an increased risk of bladder cancer, and she suggested that motor exhaust, particularly exhaust from diesel engines, may play a role in the development of the disease.
She was also a key contributor to research that documented for the first time the pattern of risk of bladder cancer following smoking cessation. Her most recent work suggests that increased urinary frequency and increased water intake have independent protective effects on bladder cancer risk.
Dr. Silverman leads two large studies of bladder cancer that are revealing new insights into environmental determinants, for example, components in drinking water like arsenic and disinfection byproducts.
In the 1990s, her studies of risk factors for pancreatic cancer solidified the evidence that cigarette smoking contributes to this disease. She was also among the first to suggest that elevated body mass index, history of diabetes, and hyperinsulinemia play an etiologic role.
One of her most challenging projects thus far, she says, is a 16-year study of the effects of occupational exposure to diesel exhaust on lung cancer risk in a cohort of more than 12,000 nonmetal miners who, because they work with diesel equipment in confined spaces underground, are exposed to diesel exhaust at levels an order of magnitude or more higher than those of other occupationally exposed groups. The study is expected to clarify the role diesel exhaust plays in lung cancer etiology.
Epidemiologic studies - whether in the occupational setting, such as the Diesel-Exposed Miners Study, or in the general population, such as the New England Bladder Cancer Study - are complex undertakings that often take a decade or more to complete. They involve state-of-the-art retrospective exposure assessment in the workplace and in the environment, in-depth interviews with participants, and the collection of biological samples from thousands of people.
"The methodologic challenges to studying occupational and environmental carcinogens require a huge commitment from the research team," she explains. "This approach exemplifies the complex, long-term studies that are hallmarks of the NIH intramural research program."
As chief of the NCI's Occupational and Environmental Epidemiology Branch, an appointment she received earlier this year, Dr. Silverman says she is excited to be leading the branch at a time when interdisciplinary research is becoming an increasingly important focus. In the era of genomic science, Dr. Silverman is championing the study of interactions between environmental/occupational hazards and genetic susceptibility. Her methodologic rigor in combining epidemiology, genetics, statistical analysis, and emerging technologies is one of the elements that make her so well suited for the job, says Dr. Joseph F. Fraumeni, Jr., director of NCI's Division of Cancer Epidemiology and Genetics (DCEG).
While carving out her reputation as an internationally respected epidemiologist, Dr. Silverman was able to raise two daughters, working part-time for many years. Juggling a scientific career with motherhood was a challenge, she says, and she now mentors many junior scientists who face the same work-life balance issues, a contribution for which she received the DCEG Mentoring Award.
"Cancer research is an extremely demanding career," she says, "but I think it's important for talented young women scientists to know it's possible to successfully balance a scientific career with the demands of raising a family."