Dr. CJ Tseng
Breast Cancer |
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Introduction
Breast cancer is the malignant proliferation of epithelial cells that line the ducts or lobules of the breast. In 2004 there were about 216,000 cases of invasive breast cancer and 40,000 breast cancer deaths in the United States. Breast cancer is a hormone-dependent disease. For example, women without functioning ovaries and who never received estrogen replacement do not develop breast cancer. Nearly half of all patients who are treated for apparently localized breast cancer develop metastatic disease. And half of all initial cancer recurrences occur more than 5 years after initial therapy. Although a very small number of these patients can enjoy long remissions when treated with combinations of systemic and local therapy, most eventually succumb to their cancer. |
Staging and Prognosis The prognosis for breast cancer generally depends on its stage and there are typically five stages (0 to 5) with sub-stages:
T= Status of Primary tumor; N = Regional lymph nodes; M = Distant Metastases
Treatment
Radiation is often prescribed in an attempt to reduce the rate of recurrence. In addition, chemotherapy is typically prescribed for women with cancer detected in the lymph nodes. However, there is little agreement about optimal chemotherapy regimens and most comparisons of chemo drugs show little difference among them. Different combinations of chemotherapy (include high dose chemotherapy with autologous bone marrow transplantation) have been found to improve response rates somewhat, but they have little effect on survival. Many breast cancers (primary and metastatic) are hormone dependent. This means that the tumor cells may have receptors for estrogen and/or progesterone. In most patients, the initial endocrine therapy is the anti-estrogen drug tamoxifen. The median survival of breast cancer patients with metastatic disease is about 2 years but many patients with hormone dependent tumors may live longer. New breast cancer treatments include attempts to block the cell surface receptor erB2, anti-angiogenic therapies, and agents aimed at blocking cell surface tyrosine kinases and other signaling pathways. The treatment results and survival rates of some of these therapies have been reported.
Treatment Results The Cancer Monthly database currently has the clinical results (survival, side effects, and more) for 50 recent breast cancer therapies including hormone therapy, biological therapy, immunotherapy, gene therapy and chemotherapy.
Source: Marc E. Lippman, Breast Cancer, in HARRISON'S PRINCIPLES OF INTERNAL MEDICINE, pt. 5 § 76, at 516-523 (Dennis L. Kasper, M.D. et al., eds, 16th ed 2005).
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