Breast Health
Estrogen Receptor Status May Determine Chemotherapy UseThe benefit of breast cancer chemotherapy may depend on the status of estrogen receptors lying on the surface of tumor cells, according to an analysis reported in the Journal of the American Medical Association (JAMA).  "Chemotherapy is helping [treat] estrogen receptor-negative tumors much more than estrogen receptor-positive," says study lead author Dr. Donald Berry, chairman of the department of biostatistics and applied mathematics at the M.D. Anderson Cancer Center. That has been suspected for a long time, experts note, but this new analysis lends more credence to the theory. Breast tumors are classified as either estrogen receptor-positive or negative, depending on cellular receptivity to the hormone. "An estrogen receptor-positive tumor has lot of receptors for estrogen, and estrogen is the fuel that drives the breast cancer," explains Dr. Berry. Typically, he says, women with cancers that have spread to nearby lymph nodes are given chemotherapy. Those with estrogen receptor-positive tumors are also prescribed tamoxifen, which inhibits estrogen uptake by cancer cells. Breast cancer is the most common cancer among women, except for nonmelanoma skin cancers, according to the American Cancer Society (ACS). The chance of developing invasive breast cancer at some time in a woman's life is about one in eight (13 percent of women). It is estimated that in 2006, about 212,920 new cases of invasive breast cancer will be diagnosed among women in the US, states the ACS. Carcinoma in situ (CIS) accounts for about 61,980 new cases each year. CIS is noninvasive and is the earliest form of breast cancer. Breast cancer also occurs in men. Approximately 1,720 cases of invasive breast cancer were diagnosed in men in 2005. Breast cancer is the second leading cause of cancer death in women, exceeded only by lung cancer. Chemotherapy a Plus for ER-NegativeDr. Berry's team analyzed data from three clinical trials conducted over the past 20 years with a total of 6,644 patients. The researchers found that 22.8 percent more estrogen receptor (ER)-negative patients were disease-free after five years if they got chemotherapy, compared with 7 percent of the ER-positive patients. Improvements in survival were 16.7 percent for patients with ER-negative tumors, versus 4 percent for ER-positive. Put another way, "one in six women with ER-negative are alive after five years because of the improvement in chemo," says Dr. Berry, whereas just "one in 25 women who are ER-positive are alive after five years because of the improvements." Dr. Kent Osborne, director of the Cancer Center at the Baylor College of Medicine in Houston, calls the new analysis good news. "This is a little bit stronger data than some of the earlier studies published a long time ago, which were sort of anecdotal series." However, Dr. Osborne points out that, due to a lack of data, Dr. Berry's team "only looked at whether the tumor was ER-positive or ER-negative. There are degrees of being positive." The new analysis should help women and their doctors make important treatment decisions, the experts say. Benefit May Be Small for ER-Positive"There is a growing body of evidence, and this is one, that suggests the chemotherapy benefit to patients in those with estrogen receptor-positive is much less," says Dr. Osborne . "When patients are trying to decide whether to take chemotherapy or not, they need to be aware [that] yes, there may be a benefit, but it is likely to be very small if they are estrogen receptor-positive, particularly if they are strongly estrogen receptor-positive," he says. Dr. Berry says, "It's a very clear decision to get more intensive chemotherapy for estrogen receptor-negative [tumors]. It is less clear for estrogen receptor-positive." "About 60 to 65 percent of breast cancers are estrogen receptor-positive but it depends on age," says Dr. Berry. "The older the woman, the more likely she is to be ER-positive." Always consult your physician for more information. Online Resources(Our Organization is not responsible for the content of Internet sites.) Centers for Disease Control and Prevention (CDC) Department of Defense - Breast Cancer Program Journal of the American Medical Association (JAMA) National Cancer Institute (NCI) National Comprehensive Cancer Network National Institutes of Health (NIH) National Surgical Adjuvant Breast and Bowel Project |
June 2006Estrogen Receptor Status May Determine Chemotherapy Use Chemotherapy a Plus for ER-Negative Benefit May Be Small for ER-Positive Hormone Treatment for Estrogen Receptor-Positive Patients Hormone Treatment for Estrogen Receptor-Positive PatientsThe National Comprehensive Cancer Network (NCCN), a group of leading cancer centers in the US, summarizes expert opinion on estrogen receptor-positive patients. The NCCN states that estrogen, a hormone produced mostly by the ovaries, but also from hormones produced by the adrenal glands and fat tissue in a woman’s body, causes some breast cancers to grow. Physicians use several approaches to block the effect of estrogen or to lower estrogen levels. These approaches can be divided into two main groups. Medications that block the effect of estrogen on cancer cells are called anti-estrogens. These medications have no effect on estrogen levels; instead, they prevent estrogen from causing the breast cancer cells to grow. Medications that lower the production of estrogen in the body are used in two situations. One situation, according to the NCCN, is when hormone receptor-positive cancers appear to have been completely removed by surgery. In this case hormone therapy is used as adjuvant therapy to kill any remaining breast cancer cells that may have been missed during surgery. In the second situation, hormone therapy may be used alone or in combination with chemotherapy. an example is women whose cancer remains after surgery or in whom the cancer comes back months or years after surgery. Hormone medications are only effective in women whose cancer have the estrogen or progesterone receptor, according to the NCCN. Every breast cancer is tested for this protein, and you should ask your physician for the result of this test on your cancer. If the cancer is negative for both these receptors, then the hormone medications are of no benefit. Anti-Estrogen Medications Tamoxifen is the antiestrogen medication used most often. Taking tamoxifen as adjuvant therapy after surgery, usually for five years, reduces the chances of hormone receptor positive breast cancers coming back. Tamoxifen is also used to treat metastatic breast cancer. In many women, tamoxifen causes many symptoms of menopause including hot flashes, vaginal discharge, and mood swings. Tamoxifen has two rare but more serious side effects. These side effects are a slightly increased risk of developing cancer of the lining of the uterus (endometrial cancer) and uterine sarcoma, and a slightly higher chance of developing blood clots. For most women with breast cancer, the benefits of taking the medication far outweigh these risks, explains the NCCN. Toremifene is another antiestrogen closely related to tamoxifen. It may be an option for postmenopausal women with metastatic breast cancer. Fulvestrant is a newer drug that reduces the number of estrogen receptors. It is often effective even if the breast cancer is no longer responding to tamoxifen. Hot flashes, mild nausea, and fatigue are the major side effects. Drugs that Lower Estrogen Levels Aromatase inhibitors stop estrogen production in postmenopausal women. These medications are anastrozole, letrozole, and exemestane. They work by blocking an enzyme that makes small amounts of estrogen in postmenopausal women. They cannot stop the ovaries of premenopausal women from making estrogen. For this reason they are only effective in postmenopausal women. For premenopausal women, tamoxifen remains the best medication to use, says the NCCN. The aromatase inhibitors have been compared with tamoxifen as adjuvant hormone therapy. They have fewer side effects than tamoxifen because they do not cause cancer of the uterus and very rarely cause blood clots. They can, however, cause osteoporosis and bone fractures because they remove all estrogen from a postmenopausal woman. They also cause side effects of hot flashes and sometimes joint pain. Always consult your physician for more information. |