Duke Cancer Institute Notes
Published: Oct. 24, 2011
Updated: Oct. 24, 2011
Ovarian cancer is a relatively rare, but highly lethal, disease.
It is the eighth most commonly diagnosed cancer among U.S. women (to put it in perspective, there are about 20,000 cases per year in the U.S., versus about 200,000 for breast cancer), but the fifth most common cause of cancer death among American women.
Unfortunately, because no screening test exists and early symptoms tend to be vague, most women are not diagnosed until the disease has reached stage 3 or 4, when it is more difficult to treat.
Although African American women have lower incidence rates for ovarian cancer, they have worse survival rates from this disease. And, although survival rates for Caucasian women have improved modestly over the past four decades, there has been no improvement for African American women.
Why is there such a major difference between African American and Caucasian women when it comes to developing and surviving ovarian cancer? No one yet knows the answer, but a team of Duke Cancer Institute (DCI) researchers is working to solve this medical mystery.
Answering questions about risk factors for disease in a specific group of people is the purview of epidemiologists. Joellen Schildkraut, PhD, and Patricia Moorman, PhD, are Duke epidemiologists who specialize in ovarian cancer. They have collaborated with Andrew Berchuck, MD, director of Duke’s Division of Gynecologic Oncology, on a variety of studies to identify the causes of ovarian cancer.
For the past decade, Schildkraut has led the North Carolina Ovarian Cancer Study (NCOCS), a study of more than 1,000 women -- both those diagnosed with ovarian cancer and a similar control group who have not been diagnosed -- to look at potential genetic and lifestyle risk factors.
The ongoing study includes just 144 African American women -- a proportion much lower than the 22 percent of North Carolina residents who are African American. This disparity is due to the lower incidence among African American women and possibly because African Americans have been less inclined to take part in medical research. Additional research is needed to understand these issues more fully.
“African Americans as well as other minority groups are under-represented in clinical research for many reasons,” says Valarie Worthy, RN, Duke’s treatment navigator for health disparities. Her job is to educate the community about cancer and clinical research using tailor-made interventions. “The community must understand that research is for the mutual benefit of all partners.”
“While African Americans are often under-represented and under-studied in research, we can’t just assume that all ovarian cancer is created equal,” says Schildkraut, who leads the DCI’s Cancer Prevention, Detection, and Control Research Program.
As they planned the next generation of NCOCS, Schildkraut, Moorman, and Berchuck, along with DCI statistician Ed Iversen, PhD, molecular biologist Jeffrey Marks, PhD, and pathologist Rex Bentley, MD, quickly recognized that the study would need to be conducted at multiple centers to get enough African American patients enrolled to yield meaningful results.
They reached out to colleagues at other medical centers and launched a multicenter collaboration with eight other sites in the East and Midwest, funded by the National Cancer Institute.
For the past year, epidemiologists and oncologists from these sites have been planning the study, developing patient brochures and questionnaires, and recruiting participants for the study. They also received the input of an African American cancer survivor to help tailor effective communications to this community.
The new study is called AACES -- the African American Cancer Epidemiology Study -- and is the first study of ovarian cancer exclusively in African American women. The goal is to enroll 1,000 women with a recent diagnosis of ovarian cancer, as well as 1,000 women who have never had the disease for comparison, in order to better understand the causes of ovarian cancer in this population.
Recruitment for the study has begun and will continue for the next four years.
African American women with ovarian cancer are identified through state cancer registries and are contacted with their physician’s consent to see if they would consider participating.
African American women without the disease are selected as part of a random sample representative of the population in the nine states where AACES is being conducted. Those who agree to participate complete a confidential, one-hour telephone interview about their medical and family history and everyday experiences and activities, complete a diet survey, and give a small blood sample.
The blood samples are used for genetic analysis, while the questionnaires provide important information on lifestyle, background, and experiences. Together, this information will help Duke researchers determine how risk factors for developing and surviving ovarian cancer in African Americans differ from those of Caucasian women, and explore other relevant factors including issues of access to care, obesity, or socio-economic status.
Because ovarian cancer is not very common, developing effective screening tests for the entire population -- like mammograms for breast cancer or colonoscopies for colon cancer -- may be cost-prohibitive.
But, notes Berchuck, results from AACES and similar studies could help identify and target specific populations that are more at-risk. “It would be great if we could identify genetic factors so we could say, ‘The average woman’s risk for developing ovarian cancer is around 1 percent, but because you have these genetic factors, your risk is 3 percent or 5 percent.’ For those identified at higher risk, we could take preventive measures to reduce that risk.”
DCI investigators will share data from AACES with their colleagues in the international Ovarian Cancer Association Consortium, greatly expanding the number of cases of African American descent that are currently in the consortium’s database.
“Ultimately, we hope that AACES will help us identify risk factors for both incidence of the disease and those that predict survival, and that this knowledge can be used to develop interventions to reduce mortality from ovarian cancer in all women,” says Moorman.