New Research Targets Breast Cancer and Family History
Dr. Nadine Tung is the Director of the Cancer Genetics and Prevention Program at Beth Israel Deaconess Medical Center, which evaluates patients who are at an increased risk of hereditary cancer. As a breast medical oncologist who specializes in treating women with a hereditary predisposition to breast cancer and/or ovarian cancer, Dr. Tung is part of a soon-to-be-launched multi-center clinical trial that will compare the effectiveness of cisplatin, a chemotherapy agent not typically used to treat breast cancer, with conventional chemotherapy in women with newly diagnosed breast cancer due to BRCA1 or BRCA2 genetic mutations.
Q: What are BRCA and BRCA2 mutations?
Dr. Tung: BRCA1 and BRCA2 are examples of tumor suppressor genes. When they are working correctly, these genes prevent the development of cancer. However, when BRCA1 or BRCA2 are mutated or damaged, they cease to be protective.
BRCA1 and BRCA2 were the first two genes for which an inherited genetic mutation (abnormality) was found to predispose a woman to both breast and ovarian cancer. BRCA1 and BRCA2 mutations account for approximately five percent of all cases of breast cancer but, in the Ashkenazi Jewish population, that figure increases to 10 percent. Mutations can be inherited from either one's mother or father, and inherited mutations also increase the risk of other cancers, including prostate cancer in men.
Q: Tell us more about your new research. Why are you investigating the drug cisplatin in women with BRCA1/2-associated breast cancers?
Dr. Tung: Cisplatin is a chemotherapy drug that has been used to treat many other cancers (including ovarian cancer), but is not typically used to treat breast cancer. However, there is evidence to suggest that it might be a beneficial treatment in breast cancers caused by BRCA1 or BRCA2 mutations.
Q: Why is that?
Dr. Tung: Within the cell, one of the major responsibilities of the BRCA1 and BRCA2 genes is to repair breaks in our DNA (genetic material). When the BRCA genes are mutated, they are unable to repair these breaks. Because cisplatin specifically works by creating many breaks in the two DNA strands, we think that breast cancers with BRCA mutations might be particularly sensitive to cisplatin. In fact, data in small studies has already found this to be the case.
Our new study, which is a large multi-center clinical trial located at several different medical centers, will randomly assign women to receive either conventional chemotherapy (i.e., doxorubicin and cyclophosphamide known as "AC") or cisplatin in order to determine which is more effective in treating these types of cancer.
Q: How might this study change the need for genetic testing in women who are newly diagnosed with breast cancer?
Dr. Tung: Genetic testing is usually done to predict the likelihood that future cancers will develop, so that patient can decide how best to manage their risk, with either increased surveillance (e.g. breast MRIs), preventive medications (e.g. tamoxifen) or prophylactic surgeries (e.g. oophorectomies or mastectomies).
Genetic testing is not currently used to make treatment decisions about a cancer once it has already developed. However, if the optimal chemotherapy to treat breast cancer in women with BRCA1 and BRCA2 mutations is different than the chemotherapy that is typically used to treat breast cancer, then genetic testing can help chart a woman's treatment course and should ideally be performed soon after a diagnosis is made.
While a strong family history of breast or ovarian cancer is what often triggers genetic testing for BRCA mutations, some studies have found that a significant number of women with BRCA mutations have no such family history. Consequently, if the optimal therapy for breast cancer differs according to whether a BRCA mutation exists, then we may need to expand the criteria for who should undergo genetic testing, in order to not miss those women who might benefit from alternative cisplatin chemotherapy.
Learn more about Breast Cancer Genetic Risk Assessment »
Above content provided by Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.
Posted March 2012