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Page 1 of 10 Updated: 06/15/2004Most women share a common fear: developing breast cancer. This is not an unfounded fear when considering that, except for lung cancer, breast cancer is the most common cancer found in women, accounting for one of every three diagnoses. However, men are also affected by breast cancer. In 2002 the American Cancer Association estimate that 1500 men will be diagnosed with breast cancer, and 400 will die as a result. In 2001 an estimated 192,200 American women were diagnosed with breast cancer and 39,600 women died of the disease (The American Cancer Association). In 2004 an estimated 203,500 new cases of breast cancer will be diagnosed in America. WHAT IS BREAST CANCER?Breast cancer occurs when cells in the breast tissue divide and grow without control. The cell cycle is the natural mechanism that regulates the growth and death of cells. When the normal cell regulators malfunction and cells do not die at the proper rate, there is a failure of cell death (apoptosis) therefore cell growth goes unchecked. As a result, cancer begins to develop as cells divide without control, accumulating into a mass of extra tissue called a tumor. A tumor can be either non-cancerous (benign) or cancerous (malignant). As a tumor grows, it elicits new blood vessel growth from the surrounding normal healthy tissues and diverts blood supply and nutrients away from this tissue to feed itself. This process is termed “angiogenesis”- the development (genesis) of new blood vessels (angio). Unregulated tumor angiogenesis facilitates the growth of cancer throughout the body.Cancer cells have the ability to leave the original tumor site, travel to distant locations, and recolonize. This process is called metastasis and it occurs in organs such as the liver, lungs, and bones. Both the bloodstream and lymphatic system (the network connecting lymph nodes throughout the body) serve as ideal vehicles for the traveling cancer. Although, these traveling cancer cells do not always survive beyond the tumor, if they do survive, the cancer cells will again begin to divide abnormally and will create tumors in each new location. A person with untreated or treatment-resistant cancer may eventually die of the disease if vital organs such as the liver or lungs are invaded, overtaken, and destroyed. Cancerous tumors in the breast usually grow slowly. It is thought that by the time a tumor is large enough to be felt as a lump, it may have been growing for as long as 10 years. This has lead to the belief that undetectable spread of tumor cells (micrometastasis) may have already occurred by the time of the diagnosis. Therefore, preventive measures such as a healthy balanced diet and lifestyle, nutritional supplementation, and exercise are of primary importance against the development of cancer. Early diagnosis is the best way to reduce the risk of dying from breast cancer. This can be accomplished by monthly self-breast exams, annual clinical breast exams and screening mammography. If breast cancer is detected, a multimodality approach incorporating nutritional supplementation, dietary modification, detoxification, and one or more of the following may be considered: surgery, chemotherapy, radiation, hormone therapy, or vaccine therapy. RISK FACTORSA wide variety of factors may influence an individual's likelihood of developing breast cancer; these factors are referred to as risk factors. The established risk factors for breast cancer include: female gender, age, previous breast cancer, benign breast disease, hereditary factors (family history of breast cancer), early age at menarche (first menstrual period), late age at menopause, late age at first full-term pregnancy, obesity, low physical activity, use of postmenopausal hormone replacement therapy, use of oral contraceptives, exposure to low-dose ionizing radiation in midlife and exposure to high-dose ionizing radiation early in life.Correlated risk factors for breast cancer include never having been pregnant, having only one pregnancy rather than many, not breast feeding after pregnancy, diethylstilbestrol (DES), certain dietary practices (high intake of fat and low intakes of fiber, fruits, and vegetables), tobacco, smoking, abortion, breast trauma, breast augmentation, large breast size, synthetic estrogens, electromagnetic fields, use of nonsteroidal anti-inflammatory drugs (NSAIDs), and alcohol consumption. Alcohol is known to increase estrogen levels. Alcohol use appears to be more strongly associated with risk of lobular carcinomas and hormone receptor-positive tumors than it is with other types of breast cancer (Li et al. 2003). A novel growth inhibitor recently identified as estrogen down-regulated gene 1 (EDG1) was found to be switched off (down-regulated) by estrogens. Inhibiting EDG1 expression in breast cells resulted in increased breast cell growth, whereas over-expression of EDG1 protein in breast cells resulted in decreased cell growth and decreased anchorage-independent growth, supporting the role of EDG1 in breast cancer (Wittmann et al. 2003). ANATOMY OF THE BREASTThe breast is composed mainly of fat (adipose tissue) and breast tissue, along with connective tissue, nerves, veins, and arteries. Breast tissue is a complex network known as the mammary gland. Within the mammary gland, there are 15-20 lobes or compartments separated by adipose tissue. Within each lobe are several smaller compartments called lobules.Lobules are composed of grapelike clusters of milk-secreting glands termed alveoli, which are found embedded in connective tissue. Spindle-shaped cells called myoepithelial cells, whose contractions help propel milk toward the nipple, surround the alveoli. There are about one million lobules contained within each breast (Spratt et al. 1995). The lobules are connected by tiny ducts that are joined together (much like a grape stem) into increasingly larger ducts. Within each breast there are between five and ten ductal systems, each with its own opening at the nipple. Surrounding the nipple is a darkly shaded circle of skin called the areola. The areola appears rough because it contains modified sebaceous (oil) glands. These glands secrete small amounts of fluid to lubricate the nipple during breast-feeding. Of all breast cancers, about 80% originate in the mammary (lactiferous) ducts, while about 20% arise in the lobules (IOM 1997). One of the most important distinctions to understand is the difference between invasive breast cancer and carcinoma in situ. |
