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WHAT'S NEW IN BREAST CANCER RESEARCH?
While the importance of getting mammograms and knowing your body well enough in order to detect breast cancer in its earliest possible stage cannot be stressed enough, advancements in medical technology are allowing doctors to research new ways to increase chances of survival for women who have already been diagnosed. Research is ongoing, and there are many experimental drugs being tested in clinical studies by organizations like the National Cancer Institute ( www.cancer.gov). Listed below are the options that are currently the most commonly investigated.
Aromatase inhibitors. Currently, Tamoxifen is the drug most widely being used to treat breast cancer. However, medical studies have shown Tamoxifen to interfere with antidepressants and increase the risk of cancer of the uterus and blood clots in women who are bed-ridden; thus, it may not be the best treatment option for everyone.
In new clinical studies, aromatase inhibitors, or drugs that reduce estrogen levels in your body, are being tested for effectiveness in conjunction with, or over Tamoxifen alone. Three aromatase inhibitors - anastrozole, letrozole and exemestane - were tested in various combinations (for example, some women received anastrozole instead of Tamoxifen as an initial adjuvant therapy). The New England Journal of Medicine reported a study using 5,000 postmenopausal women; half of which took Tamoxifen for two to three years and then switched to an aromatase inhibitor, while the other half continued the typical five-year course of Tamoxifen. After nearly three years, the women who combined Tamoxifen and an aromatase inhibitor had 32% fewer spreading or recurrences of their breast cancer, and half as many new cancers develop in their other breast.
It is important to note that there are side effects associated with aromatase inhibitors; bone loss, joint pain and hot flashes may occur, and vaginal bleeding, discharge and endometrial cancer - while less commonly reported in women using aromatase inhibitors than in those using Tamoxifen - can occur as well. More trials have to be done in order to learn about how effectively these aromatase inhibitors reduce breast cancer risk for all women, and if they should replace Tamoxifen entirely or be paired with this widely used drug.
Lapatinib. The American Society of Clinical Oncology is experimenting with a new drug called Lapatinib, which is being tried out on women who don't respond to traditional therapies. The drug works by helping to block the action of two growth factors that stimulate breast cancer. In trials, 46% of those who took Lapatinib experienced tumor shrinkage or a halting of their tumor's growth, and 24% of those who took the drug for four weeks experienced this as well.
COX-2 inhibitors. These nonsteroidal anti-inflammatory drugs are typically used to treat pain, but researchers believe they may help protect against breast cancer as well. These drugs include medications like Celebrex and Bextra. COX-1 and COX-2 are genes that indirectly stimulate estrogen production, and blocking this activity may keep tumors from forming. The COX-2 inhibitors may also be an effective treatment for existing cancers.
Paclitaxel plus cyclophosphamide and doxorubicin. In clinical trials conducted by the National Institue of Health (www.nih.gov), findings have show that paclitaxel, a chemotherapy drug that is extracted from the bark of the Pacific Yew tree, can help women with tumors that have spread to other parts of the body when it is combined with other drugs (namely cyclophosphamide and doxorubicin).
Retinoids. These natural or synthetic forms of vitamin A may be able to destroy or inhibit the growth of cancer cells, and may also be effective in premenopausal women and in women whose tumors aren't estrogen-positive.
Flax seed. Flax seed is high in the phytoestrogen lignan, which may inhibit estrogen production and stop the growth of breast cancer tumors. These phytoestrogens are naturally occurring compounds that lower circulating estrogens in your body, which would make it an encouraging development, as it is a natural food rather than a drug.
THE FUTURE OF BREAST CANCER TREATMENT
The results of an important study released in late April 2005, suggest that the breast cancer treatment drug, Herceptin, typically used to treat advanced-stage breast cancer patients, may be beneficial to many early-stage patients as well.
The five-year clinical trials on over 3,300 HER-2 (a particularly aggressive form of the cancer which causes cells to reproduce at a highly rapid rate) has found that when taking Herceptin, as well as receiving chemotherapy, patients were 52 percent less likely to experience tumor recurrence. In a statement released by the study sponsor, National Cancer Institute (NCI), Dr. Edward Romand, a study chair stated, "For women with this type of aggressive breast cancer, the addition of trastuzumab (Herceptin) to chemotherapy appears to virtually reverse prognosis from unfavorable to good." NCI Director Dr. Andrew C. von Eschenbach added, "These results are one more example that we are at a major turning point in the use of targeted therapies to eliminate suffering and death from cancer."
HER-2 affects approximately 20 to 30 percent of all breast cancer patients and makes the illness more difficult to treat. Herceptin is especially effective in women with HER-2 because of its ability to target cancerous cells, while leaving healthy cells unaffected. More detailed results of the study are to be released during the American Society of Clinical Oncology annual meeting on May 16, 2005.
According to the National Health Institute's website (www.nih.gov), several new technologies are making the future of breast cancer treatment easier and more streamlined. Doctors will be able to insert a miniature camera through the nipple and into a milk duct in order to examine the area for cancer. Also being tested is a technique involving the insertion of a catheter into the breast to deliver tiny radioactive beads to the place where the cancerous tissue was removed in an effort to reduce radiation therapy time to a matter of days.
In January, 2005, a potentially exciting advancement in the treatment of breast cancer occurred with the approval of the drug Abraxane by the FDA.
After a decade of clinical trials were conducted to study the effects of this nanoparticle drug, researchers were finally able to determine that using Abraxane instead of Taxol doubled the response rate and slowed the rate of tumor growth in patients with metastastic breast cancer.
Abraxane combines the drug paclitaxel with a natural protein called albumin, which turns into a nanoparticle when injected into the bloodstream, allowing a greater concentration of the drug in the tumor and starving the malignant cells of the nutrients they need to grow. The drug was developed in order to combat the toxicity associated with drugs like Taxol, which contain solvents Cremophor-EL and alcohol.
Additional resources used for research:
The American Cancer Society: www.cancer.org
The American Cancer Society cancer information hotline can be reached from the United States, 24 hours a day, 7 days a week, by simply dialing: 1-800-ACS-2345
CBS Cares would like to thank Dr. Debbie Saslow of the ACS for her expertise and time and Susan Raphael of the ACS for facilitating those discussions.
The Mayo Clinic: www.mayoclinic.com
Susan G. Komen Foundation: www.komen.org
National Institute of Health: www.nih.gov
National Cancer Institute: www.cancer.gov
Journal of the American Medical Association, 2004
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