Breast Health |
More Evidence Found Linking HRT To Breast Cancer RiskWarning Continues Against Combined HRTYet another study has found an apparent increased risk of breast cancer in older women who have taken combined hormone replacement therapy for at least five years. The latest study, reported in the Journal of the American Medical Association (JAMA), found that the increased risk held true regardless of the pattern of progestin use, a hormone used in tandem with estrogen. "I think the new study that we have just further characterizes risk of combined therapy," says Dr. Christopher Li, lead author of the study and researcher at the Fred Hutchinson Cancer Research Center in Seattle. Experts Concur on Newest EvidenceDr. Jay Brooks, chief of hematology/oncology at the Ochsner Clinic Foundation in Baton Rouge, La., says "This is just another piece of evidence that shows that combined estrogen/progesterone hormone replacement increases the risk of breast cancer. "This is another example of why these two types of medicines used together should not be used, if at all possible, by women," Dr. Brooks says. Hormone replacement therapy (HRT) is prescribed to control symptoms of menopause, such as hot flashes. Because estrogen increases the risk of endometrial cancer in women, it is taken with progestin, which mitigates that effect. HRT can either be taken continuously (estrogen and progestin every day) or sequentially (estrogen daily and progestin for about 10 days every month). Last summer, a large study called the Women's Health Initiative found that women taking combined hormone therapy experienced a 26 percent increase in invasive breast cancer rates, compared to women taking a placebo (inactive pill). Because of this and other health risks, the trial using the two hormones together was stopped. Most of the women participating in the WHI were taking continuous hormone replacement therapy. The new study assessed both continuous and sequential treatments by looking at HRT use in 975 women who had been diagnosed with breast cancer, along with 1,007 "controls" -- women who were free of the cancer. Study's Detailed Analysis HelpfulDr. Li and his colleagues found a 50 percent increased risk of invasive ductal carcinoma, which affects the milk ducts carrying milk to the nipple and represents about 80 percent of all breast cancers. There was a 170 percent increased risk of invasive lobular breast cancer. Lobular breast cancer is the second most common type of breast cancer and involves the areas of the breast that contain the milk-producing glands. Women who took combined HRT had twice the risk of hormone-receptor-positive breast cancer. These tumors need either estrogen or progesterone to grow. Women who took "unopposed estrogen" - or estrogen without progestin even for as long as 25 years - did not have any greater risk of breast cancer, the study found. "Unopposed estrogen was not associated with breast cancer even if it was used for a long period of time," Dr. Li says. "Combined therapy was associated with an increased risk of breast cancer. It didn't matter whether women took sequential or continuous. Both increased breast cancer risk but only if they had used it for five years or longer." Dr. Li says, "Now that the WHI results have been published and there's a greater sense among women that maybe they should stop taking HRT, we'll be able to evaluate women who stopped HRT use. Does their risk of breast cancer go back to baseline or will it stay elevated?" Always consult your physician for more information. What Are the Risk Factors for Breast CancerAny woman may develop breast cancer. However, the following risk factors may increase the likelihood of developing the disease. Risk factors that cannot be changed: gender The most frequently cited lifestyle-related risk factors: smoking not having children, or first child after age 30 oral contraceptives obesity and a high-fat diet physical inactivity alcohol long-term, post-menopausal use of combined estrogen and progestin (HRT) weight gain and obesity after menopause Environmental risk factors: exposure to pesticides, or other chemicals Always consult your physician for more information. Online Resources(Our Organization is not responsible for the content of Internet sites.) American Society for Clinical Oncology Centers for Disease Control and Prevention (CDC) National Cancer Institute (NCI) National Human Genome Research Institute (NHGRI) |
August 2003More Evidence Found Linking HRT To Breast Cancer Risk Experts Concur on Newest Evidence Study's Detailed Analysis Helpful What Are the Risk Factors for Breast Cancer Experts Discuss Treatment in Women at High Risk for Breast and Ovarian Cancer Experts Discuss Treatment in Women at High Risk for Breast and Ovarian CancerThe Dutch authors say studies examining the value of prophylactic surgery to prevent breast or ovarian cancer in women at high risk for these cancers may have overestimated or underestimated the benefits because of potentially unrecognized biases in study design. Scientists try to remove any elements of bias from studies in order to obtain the most accurate findings in a study. Recognizing and understanding these biases may help scientists improve the design of future studies and better evaluate the results of previous studies, the authors say. The discussion comes in a recent commentary in the Journal of the National Cancer Institute. Women with certain mutations in the breast and ovarian cancer susceptibility genes BRCA1 and BRCA2 have an increased risk of developing breast and ovarian cancer. Both BRCA1 and BRCA2 are tumor suppressor genes that usually have the job of controlling cell growth and cell death. Everyone has two BRCA1 (one on each chromosome #17) and two BRCA2 genes (one on each chromosome #13). When a person has one altered or mutated copy of either the BRCA1 or BRCA2 gene, their risk for various types of cancer increases. Previous studies found prophylactic bilateral breast removal is associated with an 85 percent to 100 percent reduction in breast cancer risk. Other studies concluded that surgery to remove the ovaries is associated with a similar risk reduction for ovarian and breast cancer. But these studies contain a number of potential biases, according to the commentary. These include familial-event bias, survival bias, detection bias, testing bias, and confounding by other risk factors for breast and ovarian cancer. These biases need to given serious consideration and warrant critical discussion about their potential impact on study results. "Only in this way can BRCA1/2 mutation carriers, clinical geneticists, and treating physicians obtain more accurate information about the true extent of cancer risk reduction from prophylactic surgery. "This valid estimate of risk reduction may become even more crucial in the future when data become available regarding the efficacy of new surveillance methods, such as magnetic resonance imaging (MRI), and new chemoprevention agents, such as raloxifene," the authors write in press statement. Always consult your physician for more information. Genetics of Breast CancerAccording to the National Cancer Institute (NCI), the lifetime risk for a woman to develop breast cancer is nearly 13 percent (one in eight), while the lifetime risk to develop ovarian cancer is a little greater than 1 percent (one in 70). Approximately 5 percent to 10 percent of breast and ovarian cancers are due to known predisposing genetic factors. This means that the majority of breast and ovarian cancers are, in fact, not inherited. A gene is a basic unit of heredity that determines a person’s traits. Genes are located on one of the 46 chromosomes housed within cells that make up all of the tissues of the body. They come in pairs, and work together to make proteins. One member of the gene pair is inherited from the mother, and one from the father. Cancers develop due to alterations (mutations) in genes. When an alteration or mutation in a gene is present in the eggs and sperm, also called germ cells, it is referred to as a “germline mutation.” When a germline mutation is inherited it is present in all body cells. Only a small percentage of cancers involve inherited mutations that are passed from generation to generation. The majority of cancers can be attributed to acquired mutations. “Acquired” means that the mutations occur only in the tissue that is affected by cancer and are not present in all cells of the body. Acquired mutations are not inherited and are not passed down to our children.< /p> Always consult your physician for more information. |
