GU Researchers Help Discover When Breast Cancer May Recur
December 8, 2011 – Researchers led by a Georgetown physician have found differences in genes and patterns of genes among women whose breast cancer comes back within a few years compared to those with cancers that recur much later.
The findings, presented Dec. 4 at the 2011 San Antonio Breast Cancer Symposium, may help oncologists find ways to individualize treatment that could delay or ultimately prevent cancer’s return, as well as prevent overtreatment of patients whose cancers may never recur.
The symposium is sponsored by the Cancer Therapy & Research Center at University of Texas Health Science Center in San Antonio and the American Association for Cancer Research.
At the time of diagnosis, breast tumors are tested to see whether or not estrogen and/or progesterone are fueling their tumor. Cancer that is hormone-positive (ER+) typically grows a little more slowly and has a better chance of responding to anti-hormone treatment.
“We found that, at the time of diagnosis, there are clear biological differences within the supposedly uniform group of hormone receptor positive breast cancers, and these differences distinguish subtypes relative to the time at which they recur,” says Dr. Minetta Liu, director of translational breast cancer research at the Georgetown Lombardi Comprehensive Cancer Center.
“We need to exploit these differences and use our data to figure out what drives a tumor to never metastasize,” she adds. “Then we will try to manipulate the cancers that are programmed to recur to act like that of the non-recurrences.”
When Cancer Returns
Tamoxifen is credited with saving the lives of thousands of women with (ER+) breast cancer, which accounts for two-thirds of all diagnoses of invasive breast cancer in the United States.
As the world’s leading breast cancer treatment and prevention drug, tamoxifen can stave off cancer for more than 10 years in some patients, but for others, the cancer returns much earlier.
To determine why some ER+ cancers treated with tamoxifen come back earlier rather than later, if at all, Liu and her Georgetown team collaborated with researchers at the University of Edinburgh and with engineers at Virginia Tech.
The Scottish collaborators shared high-quality tumor biopsies collected from patients with different stages of breast cancer before they had started tamoxifen therapy.
Critical clinical information was available to determine whether or not patients developed metastatic disease, and when the recurrence (if any) was found.
The samples were processed and analyzed at Georgetown. Then scientists at Virginia Tech examined the gene expression patterns from the tumor biopsies relative to the known clinical outcomes to develop a predictive model of early, late or no disease recurrence.
Ability to Predict
The final analysis revealed distinct patterns in cancers that recurred early (up to three years from diagnosis) or late (more than 10 years from diagnosis).
The U.S. Department of Defense and Scotland’s Breakthrough Breast Cancer program funded the research.
“The ability to predict which patients will recur early in their treatment course can lead to more appropriate recommendations for adjuvant chemotherapy,” Liu says. “It might also identify those women who would benefit most from studies using investigational agents to enhance the effects of tamoxifen or aromatase inhibitors.”