Cancer is a complex and too often devastating disease. Even with modern medicine’s latest techniques and most powerful tools for diagnosis and treatment, nothing compares to preventing it in the first place. The good news is that as many as half of all cancer cases are preventable.
The prescription for cancer prevention, at least for those factors under our control, is familiar: eat fresh fruits and vegetables, exercise daily, maintain a healthy weight, don’t smoke and get the recommended screenings. And the health benefits go beyond preventing cancer.
“That’s one of the great things about prevention: one lifestyle choice can have a beneficial effect on multiple cancers as well as other chronic diseases,” says Kathleen Wolin, ScD, a behavioral epidemiologist and prevention expert at the Alvin J. Siteman Cancer Center at Barnes- Jewish Hospital and Washington University School of Medicine. “Physical activity is going to reduce your risk of colon and breast cancer. It’s also going to reduce your risk of heart disease, stroke and diabetes.”
But prevention is difficult to measure.
“You don’t have champions who say, ‘Your study prevented my prostate from becoming cancerous,’” says Graham Colditz, MD, DrPH, associate director of prevention and control at Siteman. “It’s one of the bigger challenges of getting people excited about prevention.”
And Colditz is excited about prevention. When he came from Harvard University in 2006 he was drawn to Washington University and Siteman because of their commitment to supporting the growth of prevention research and community outreach.
He brought with him an interactive website called “Your Disease Risk,” an important part of Siteman Cancer Center’s efforts to get prevention messages to the community. He has helped recruit dozens of prevention and public health experts to Siteman and Washington University.
Genes vs. Lifestyle
A person’s risk of developing cancer involves an array of interacting factors: diet, exercise, weight, genetics, family history, infection exposure and access to screening. Colditz’s team studies all these, searching for causes and ways to prevent cancer of all types, from breast to colon to blood cancers such as leukemia. In addition to prevention, they are working to improve survival and quality of life after cancer diagnosis and treatment.
A look at several projects devoted to prostate cancer illustrates the breadth and cross-disciplinary nature of prevention research at Siteman. Urologic surgeon Adam Kibel, MD, treats prostate cancer patients and is interested in the genetics of the disease.
“We’re trying to look at the genetic basis for aggressive prostate cancer,” Kibel says. “The majority of the disease that’s diagnosed is not very aggressive. So the critical issue is not whether you have prostate cancer but whether you have the kind of prostate cancer that is going to cause you harm.”
Because Kibel can draw from a large population of patients treated for prostate cancer at Siteman, he can gather valuable information about diet, exercise and even infection exposure that, along with the genetic data, can provide new insights into disease risk.
“Dietary information is useful because we can look at gene-environment interactions,” he says. “It could be that the right gene in the right environment dramatically increases or decreases a man’s risk of getting prostate cancer.”
More specifically, Colditz says, “Are there subsets of men for whom vegetables are really fantastic at preventing progression of their cancer? Or is it vitamin D or physical activity? Are there subsets of people in Dr. Kibel’s broader clinical population where lifestyle has a substantial impact?”
Fish are Friends
To answer some of these questions, Colditz has recruited epidemiologists and public health experts who team up with physicians such as Kibel to tackle problems they might not be able to address on their own.
Bettina Drake, PhD, a Siteman epidemiologist, is interested in whether vitamin D, which is naturally found in many fish, is protective against prostate cancer. Partnering with Kibel, Drake is looking at the vitamin D levels of prostate cancer patients when they are first diagnosed and their risk for recurrence.
“Vitamin D and prostate cancer is one of those associations in the literature that has been inconsistent,” Drake says. “Some studies find no association. Other studies have found small associations.” Drake notes that African-American men are known to be at higher risk of prostate cancer than other populations. They also tend to have lower vitamin D levels. Other factors such as age and obesity can affect vitamin D levels as well.
“How all of these factors biologically work together and how it impacts cancer is complex but very interesting,” says Drake.
Eating tomato-based foods high in the compound lycopene has also been linked to a lower risk of prostate cancer. The literature often disagrees about diet-based studies, but in this case, according to Drake, the evidence tilts in favor of lycopene being protective against prostate cancer.
“If you can use a genetic marker to identify who is at risk for developing aggressive prostate cancer and then make a dietary change that decreases that risk, that’s the kind of prevention we dream about,” Kibel says.
Run it Off
Beyond diet, Wolin would like to know whether physical activity can prevent problems with urinary function and sexual activity that some men experience after prostate surgery.
“Our preliminary research suggests that men who were active, even if they were overweight or obese, have better urinary function than men who were inactive,” she says.
Kibel thinks these findings make sense. “It’s a physical act, holding in urine,” he says. “Ultimately, we’d like to be able to give people a more accurate risk assessment of their likelihood of incontinence. If we can tell someone, ‘you’re not likely to be incontinent after surgery,’ they’re going to feel a lot more comfortable proceeding with it.”
Taking a different approach, epidemiologist Siobhan Sutcliffe, PhD, is looking at possible infectious causes of prostate cancer.
“There are quite a few examples of infections that are known to cause cancer,” says Sutcliffe, citing the connection between human papillomavirus and cervical cancer, among others. “People have hypothesized that inflammation may be involved in prostate cancer development. One way you can have inflammation in your prostate is by infection.”
Sutcliffe is working with Kibel to gather and analyze prostate fluid to look for evidence of current or past infection. Of course, this kind of research requires patients who are willing to participate in studies and donate tissue samples. Another major project at Siteman is finding ways to encourage people, especially under-represented minorities, to participate in tissue research. Through the Program for the Elimination of Cancer Disparities (PECaD), Drake is conducting focus groups with African-American men to better understand barriers that might exist for participating in health research studies.
“We want to get a sense of what influences their decision and, if possible, how recruitment strategies can provide more information to help promote participation in these types of studies,” she says.
Through these and other multidisciplinary efforts, Colditz and colleagues are dedicated to making significant progress in detecting cancer early, improving quality of life, reducing recurrence and, of course, preventing cancer in the first place.