Dana-Farber's Judy Garber, MD, MPH, will present the study's data (Abstract 508) – on behalf of her colleagues at Yale University School of Medicine and more than 30 institutions and medical practices in the Cancer and Leukemia Group B consortium, a clinical research network organized by the National Cancer Institute – during an oral presentation on Sunday, May 15, at 8 a.m., Level 2, Hall A2.
The study involved more than 300 women receiving tamoxifen as "adjuvant" therapy – given after a new breast cancer diagnosis to prevent recurrence. Researchers focused on a blood-clotting protein called Factor V. Previous studies had shown that women with a specific Factor V gene mutation – which gives rise to an abnormal version of the protein, known as Factor V Leiden (FVL) – are at increased risk for blood clots when pregnant or taking oral contraceptives or estrogen replacement therapy.
In the new study, researchers found that women who had blood clots while taking tamoxifen were almost four times as likely to have an FVL mutation as were those who did not have blood clots. The results suggest that testing women in advance for FVL mutations may enable physicians to identify some women who should either use alternatives to tamoxifen or, if good alternatives are not available, use a blood thinner while taking tamoxifen.
"Other factors contributing to blood clot risk must also be considered in the decision to recommend tamoxifen to generally healthy women, including a history of previous blood clots, obesity and planned surgery," says Garber. "But FVL testing can now be used to help make this powerful medication safer for some women who need it for breast cancer treatment or prevention."
In addition to Garber, the study's other authors are Nancy Berliner, MD, Yale University School of Medicine; Susan Halabi, PhD, Duke Comprehensive Cancer Center; Ellen Kaplan, MA, CALGB Statistical Center at Duke University Medical Center; Stephen Edge, MD, Roswell Park Cancer Institute; Lynn Dressler, DrPH, UNC Lineberger Comprehensive Cancer Center; and Electra Paskett, PhD, The Ohio State University.
Dana-Farber Cancer Institute (www.danafarber.org) is a principal teaching affiliate of the Harvard Medical School and is among the leading cancer research and care centers in the United States. It is a founding member of the Dana-Farber/Harvard Cancer Center (DF/HCC), designated a comprehensive cancer center by the National Cancer Institute.