Last modified on May 22nd, 2020
What Are Cancers?Cancer cells, also called carcinomas, form by abnormal cell division. This happens when the processes that control normal tissue growth and repair breaks down leading to alterations in the proteins produced due to changes in DNA. This causes an excessive, uncontrolled growth of abnormal cells, which invade and destroy other tissues. Cancerous cells, which tend to destroy an increasing proportion of normal breast tissue over time, may spread, or metastasise, to other parts of the body. Such genetic mutations in DNA can be present at birth, predisposing a woman to getting breast cancer earlier in life, or can be caused by exposure to hormones and carcinogens (cancer-causing agents).Breast cancer is not a single disease. There probably are at least 15 different kinds, each with a different rate of growth and different tendency to metastasise (spread to other parts of the body). It is local only briefly and can develop in many parts of the breast: in the milk ducts, between ducts, in fats, in lymph or blood vessels, in the nipple, and in the lobes where milk is manufactured.Breast cancer can be referred to as being “in situ” or invasive. In situ refers to cancer that has not spread beyond its site or origin while invasive applies to cancer that has spread to the tissues around it. The most common type is invasive ductal carcinoma, accounting for about 70 to 80% of all breast cancers. It starts in a milk duct, breaks through the duct wall and invades the breast’s fatty tissue. Another 10 to 15% of breast cancers are invasive lobular carcinomas, which begin in the milk-producing glands and can spread elsewhere. Still other, rarer kinds of breast cancer tend to have a better prognosis than these two most common types.
Causes and Risk FactorsNo one knows why some women develop breast cancer and others do not. Although the disease may affect younger women, 75% of all breast cancer occurs in women age 50 or older. Several variables have been identified as risk factors for breast cancer.
Familial or Genetic RiskWomen who have had a mother or sister diagnosed with breast cancer are at almost three times the risk. Inherited mutations in breast cancer genes predispose women to both breast and ovarian cancers, often at younger ages. The major genes that increase breast cancer susceptibility are BRCA1 and BRCA2.The pattern of inheritance in families that are carriers is such that 50% of the offspring inherit the mutations. Women who are carriers of mutations in BRCA1 or BRCA2 have a lifetime risk of 56 to 87 percent for breast cancer and an elevated risk of over 40% for ovarian cancer. However, not all women with such profiles actually have either of the BRCA1 or BRCA2 gene mutations that have been identified for breast cancer. In fact, the latter mutations account for no more than 5%-10% of all breast cancers in the United States.
Exposure to EstrogenThese risk factors, all of which relate to hormone-based life events, suggest that breast cancer is somehow affected by prolonged exposure to female sex hormones, such as estrogen. Thus women with a long menstrual history who began menstruating early (before the age of 12) and stopped menstruating late (after 55) are at higher risk. At high risk consideration are nulligravida women (who have never been pregnant) and nullipara women (who have never given birth). Also women who have their first child after the age of 30 have almost a threefold increase in risk compared with those giving birth the first time at age 20 or younger.Taking estrogen, in the form of the Pill for birth control or estrogen replacement after menopause, appears to increase risk. Older women, who take hormone pills that combine estrogen and testosterone, sold under the brand names Estratest and Estratest H.S., more than double their risk of breast cancer. Similarly, medications combining estrogen and progestin greatly increase the risk.
Nutrition and Lifestyle Risk
Breast Cancer and SmokingOne important and preventable risk factor for breast cancer is cigarette smoking. The prevalence of breast cancer in smokers was approximately three times that of non-smokers. Research suggests that roughly half of all women are particularly sensitive to the carcinogens (cancer-causing substance or agent) found in tobacco and so have a higher risk of breast cancer if they smoke cigarettes. Such women have a slow-acting form of a liver enzyme that normally detoxifies carcinogens. For such women, every cigarette loads the dice in favor of breast cancer.
SymptomsWhen breast cancer first develops, there may be no symptoms at all. But as the cancer grows, it can cause changes that women should watch for. Most often, the noticeable symptoms are not cancer (like lumps – 80% of which turn out to be benign growths or cysts), but it’s important to check with the doctor so that any problems can be diagnosed and treated as early as possible. Despite the emphasis on mammography as a screening device, breast cancer is usually first discovered as a lump (usually in the upper outer quadrant) by the woman or her physician.About 85-90% of clinically discovered breast cancers present with a lump in the breast; most of the remaining 10-15% present with pain, skin or nipple retraction (5%) and discharge from the nipple (2%); pain or swelling in the axilla is also occasionally noted. A woman can help safeguard her health by learning the following warning signs of breast cancer:
- A lump or thickening in or near the breast or in the underarm area
- A change in the size or shape of the breast
- A serous or bloody nipple discharge or tenderness
- The nipple is pulled back or inverted into the breast
- Ridges or pitting of the breast – the skin looks like the skin of an orange which is often referred to as peu d’orange
- A change in the way the skin of the breast, areola, or nipple looks or feels (for example, the skin may be warm, swollen, red, or scaly)
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