SAN DIEGO – A new research study could potentially pave the way for a more individualized approach to women’s breast cancer screenings, making each person’s genetic makeup a key factor in guiding how often they get tested.
The study by Scripps Health will initially assess whether a woman’s likelihood of developing breast cancer can be more accurately predicted by the presence of recently discovered common DNA variants that are associated with the disease. If these low-risk variants prove predictive, healthy women could be divided into three different categories for breast cancer screening, instead of just one.
“During the past two years alone we’ve seen the discovery of about a dozen common DNA variants strongly associated with increased risk for breast cancer, but there hasn’t been a study yet to see just how specific and sensitive these markers are to predict breast cancer,” said Sarah S. Murray, Ph.D., one of the study’s investigators and director of genetics with Scripps Genomic Medicine. “If we can quantify people’s risk better, we can be smarter about the way we go about screening.”
Current breast cancer screening protocols are based largely on age, family history and ethnicity, with annual mammograms recommended for healthy women starting at age 40, according to the American Cancer Society.
The initiative, dubbed the PINK study, is now enrolling participants and aims to attract 3,500 women, regardless of whether they have had a breast cancer diagnosis. Scripps researchers will test all participants’ DNA for each of the known common variants and will correlate the relationships between the presence of common variants and breast cancer diagnoses.
The study is sponsored by Scripps Genomic Medicine (a program of Scripps Health), in association with the Scripps Polster Breast Care Center at Scripps Memorial Hospital La Jolla. To enroll, women must be 30 or older; have at least five years of breast imaging records available for confidential review; undergo a one-time blood sample for confidential DNA analysis; and currently receive screenings or care at Scripps Polster Breast Care Center.
The PINK study will focus on common variants since they affect a broad segment of the community – in some cases between 20 and 30 percent of the total population – and can have a significant impact on public health. Women could potentially carry these common variants but still may have no family history of breast cancer. Common DNA variants are “mistakes,” or alternative letters in the human DNA code.
Murray says if the study concludes that these common DNA variants can provide a more accurate prediction of a breast cancer diagnosis than the current model, then women could potentially be classified into three groups for more effective screening purposes:
- Women who have a lifetime risk of greater than 20 percent would be placed on a track of being more carefully screened, such as annual MRI and mammography (in accordance with National Cancer Institute guidelines);
- Women who have a lifetime risk of between 10 percent and 20 percent would receive the existing standard of care of annual mammography (the average lifetime risk in the general populations is approximately 12 percent); and
- Women who have a substantially lower-than-average lifetime risk could potentially undergo mammography less frequently than once per year.
San Diegan Tamara Knabb recently enrolled in the study as a way to contribute to future advances in the fight against breast cancer. “It’s an opportunity to do something that might help down the line, and it takes away from the feeling of helplessness,” she said. Knabb has two daughters who will begin getting their annual mammograms in the next decade or so, and hopes this research will help lead to improvements in the way they get their screenings.
“More genetic discoveries with respect to the role of common variation and breast cancer have been made in the last two years alone than in all of previous medical research history,” Murray said. “We want to see if we can take these advances and translate them into better health outcomes for patients.”
Breast cancer is the second-most common form of cancer among women in the United States (after skin cancer), with 192,370 new cases estimated for 2009 by the American Cancer Society. It is also the second-leading cause of cancer death in women (after lung cancer), with 40,170 deaths expected in 2009.
Rare, high-risk variants such as BRCA-1 and BRCA-2 are not targeted in the PINK study. “We’ve known for many years that family history is a very strong predictor,” Murray said. “This is the first breast cancer study to explore how predictive these lower-risk common variants are for breast cancer, either by themselves or in combination.”
Those interested in learning more about the PINK study can call 858-554-5753.
Founded in 1924 by philanthropist Ellen Browning Scripps, Scripps Health is a $2 billion nonprofit community health system based in San Diego, Calif. Scripps treats a half-million patients annually through the dedication of 2,600 affiliated physicians and 12,700 employees among its five acute-care hospital campuses, home health care services, and an ambulatory care network of clinics, physician offices and outpatient centers. Recognized as a leader in the prevention, diagnosis, and treatment of disease, Scripps is also at the forefront of clinical research and graduate medical education.
Scripps Genomic Medicine, an initiative of Scripps Health in collaboration with The Scripps Research Institute (TSRI), supports basic research and clinical programs focused on defining the genes that underlie susceptibility to disease. The program’s work involves genotyping tens of thousands of individuals of diverse ancestry in an attempt to identify and define genes responsible for major disease and the underpinnings of health.