According to the National Alliance of Breast Cancer Organizations, breast cancer is the second most common form of cancer in women in the United States, falling only behind skin cancers. This is why it is such an important disease to understand. Throughout this paper there will be information about various issues which deal with breast cancer, in an attempt to give better insight to the disease. First there will be a brief discussion on the normal and altered physiology of the breast followed by the etiology and possible causative factors. Next there will be signs and symptoms which result from these alterations. Finally, the paper will be ended with some complications and the prognosis of this disease.
Although breast cancer occurs in both men and women the prevalence is low in men. Out of every 100 women who are diagnosed with breast cancer only one man is which is why this paper will concentrate on the disease process in women.
Please refer to the illustration above for help in understanding the structure of a normal breast. The female breast is primarily made up of lobules, ducts, and stroma. Lobules are milk producing glands, ducts are the milk passages that connect the lobules to the nipple and stroma is fatty and connective tissue that surrounds the ducts, lobules, blood vessels and lymphatic vessels. Lymphatic vessels carry lymph, a clear fluid containing waste products and immune cells. There are also lymph nodes along the lymphatic vessels; these nodes are bean-shaped collections of immune cells. Most lymphatic vessels of the breast connect to axillary lymph nodes which can be found in the armpit. Other nodes, such as internal mammary nodes and supra/infraclavicular nodes can also be found inside the chest or above and below the collarbone.
According to NABCO cancer is a group of more than 100 different diseases and occurs when cells become abnormal and are without control or order. The cells then continue to divide if when new ones are not needed. During the change from a normal cell to a cancerous cell, however, the cells requires many different gene alterations. Eventually these altered genes form a tumor which may be benign (non-cancerous) or malignant (cancerous). A benign tumor can damage local tissue but fortunately will not spread to other parts of the body. Malignant tumors on the other hand spread to other areas of the body damaging and destroying healthy tissue.
A gene that is commonly found in breast cancer patients which have a high incidence of familial causes is the BRCA gene. Unfortunately inherited breast cancer only accounts for 10 % of the approximately 200,000 cases which are diagnosed each year. Molecular biologist, Masaaki Hamaguchi, of Cold Springs Harbor Laboratory has developed a theory that may give insight to the other 90% of breast cancer cases. While comparing healthy and cancerous cells of 200 women diagnosed with the disease his team noticed that a gene called DBC2 had been completely deleted in the cancerous cells of seven women. The team then looked at 56 more cancerous and 19 more healthy tissue samples for messenger RNA (mRNA). The mRNA showed up in all of the healthy cells while the mRNA was missing in 58% of the breast cancer tissue. This recent discovery may aid in the detection of the underlying causes of breast cancer.
As stated earlier the gene which causes inherited breast cancer is better understood. BRCA is a tumor suppressor gene. This gene is normally programmed to slow down cell division or cause cells to die at the right time. In the case of breast cancer DNA mutations cause the BRCA gene to “turn off” allowing cancer cells to multiply.
There are believed to be many risk factors of this disease, unfortunately, the reasons for the many of the risks are often unclear. The most validated reason for breast cancer is estradiol exposure. For this reason, being a woman is the greatest risk factor of all. Women have many more breast cells which are constantly being exposed to growth hormones. White women are also higher risk than their black counterparts, though the reason for this is not known.
Due to estradiol, an early onset of menses or the late development of menopause puts a woman at greater risk because there are an increased number of menstrual cycles leading to extra estradiol production. For this same reason, women whose cycles are shorter than 25 days; women who have used conventional animal estrogens or synthetic hormone for more than five years; and those women who used birth control before their first pregnancy, before 20, or for more than five years before 35 double and possibly triple the risk for developing breast cancer.
Hereditary, dietary and lifestyle factors are also contributors to beast cancer risk. Women whose mothers had breast cancer are at twice the risk for developing this disease, generally the younger the mother is at the time of diagnosis the greater the risk. If a sister has breast cancer or a brother has prostate the risk can increase even more. Diets high in fat are also linked to this illness; because more fat cells produce more estrogen, high fats promote early onset of menstrual cycle, and there are hydrogenated fats from trans-fatty acids found in margarine which are considered cacogenic. Increased alcohol consumption also promotes increased estrogen levels. Lack of regular, physical exercise can also be a risk factor, because exercise directly decreases estradiol absorption and improves immune response.
Now that some of the risk factors are known, can breast cancer be prevented? While it is not possible to completely prevent the disease it is possible to reduce the risk with a hormone called Tamoxifen. Tamoxifen is an antiestrogen drug which is most often taken in pill form for approximately five years. This hormone is not only used as a preventive treatment for development of cancer in those people who have not had it , but it is also used to prevent a second episode of the disease and to prevent further tumor development during the actual disease process. After taking the hormone for five years 49% fewer women were found to havebreast cancer than women with the same risk factors who did not take the hormone. Unfortunately, this therapy does not come without side effects. The use of this drug increases the risk for developing uterine carcinoma, a rare and potentially serious condition. Other side effects include weight gain, mood swings, hot flashes, blood clots and cataracts. Because of these serious side effects it is important for a patient to weigh their options, but more often then not the benefits prevail.
Symptoms found with breast cancer are masses, pain, erythema, nipple drainage, and enlarged lymph nodes. The most common complaint which causes women to seek medical attention is a breast mass. Approximately 90% off all masses found are due to benign lesions. Masses that are smooth and rubbery are usually a result of fibroadenoma and occur in the 20s or 30s while cysts are what are commonly found in women in their 30’s and 40’s. The etiology for fibroadenoma is unknown, but the pathogenesis is a clonal stromal component. There is proliferation of both the ducts and the stroma, numerous fibroblasts of the stroma can be seen along with a pale eosinophilic cytoplasm. The typical duct epithelium often lines the glandular spaces which may lead to compression because of this fibrous proliferation.
There are two types of breast pain, cyclic and non-cyclic. Cyclic pain is related to a woman’s cycle. Non-cyclic pain however, is often only experienced in certain area of the breast. This pain may sometimes be caused by injury or trauma to the breast such as after a breast biopsy. It is associated with both pre and post menopausal women and is most common in 40 to 50 year old. Although these pains often subside after a couple of years and are not usually associated with breast cancer the possibility still exists and therefore should be discussed with a physician.
Another symptom is erythema, an abnormal redness of the skin. There is dilation of the superficial capillaries of the skin which then leads to inflammation and redness. The tumor or cyst may cause this hypersensitive, inflammatory reaction, although it is not known for sure.
Yet another symptom related to breast cancer can be nipple discharge. The majority of nipple discharges are associated with non-malignant changes and are often caused by hormonal changes. Discharge is a concern when it is bloody, sticky and clear, brown or black, is spontaneous, or unilateral. About 90% of bloody discharges are the cause of papilloma or infection; a papilloma is a non-cancerous tumor that has a branch or stalk which reaches into the breast duct. This tumor is also malignant almost 10% of the time occurring unilaterally, so further diagnostic testing should be preformed.
Finally, discussion of the last symptom of breast cancer is enlarged lymph nodes. The enlargement is due to the production of additional white blood cells which helps ward off infection. The infections that cause this inflammation are often benign, but can be caused by the presence of cancer cells. Unfortunately, the only way to find out whether the cause of the swelling is cancerous or non-cancerous is to perform a biopsy. However, some signs are more associated with being benign, such as, a node that is less than one centimeter in size, and is soft, rubbery and tender.
Lymph nodes are also the key factors in staging breast cancer and determining the prognosis of a patient. Stage one show a tumor which is less than 2 cm in size with no lymph node involvement or metastasis. In stage four the tumor size is not applicable, nor is lymph node involvement, but there is metastasis of other tissues. In stage one there is a 98% five year survival rate while in stage four there is only a 16% five year survival rate. For this reason it is important to perform self breast exams and receive yearly mammograms after the age of 40. The sooner the cancer is detected the quicker treatment can be started, and early treatment dramatically increases chances of survival.
Complications of this disease of course include death, but also fatigue which is usually associated with the treatment of the disease. Death caused by rapidly metastasizing cancerous agent is nearly unavoidable in later stages of the disease which again is why early detection is so critical. Fatigue related to treatment, which is due to the loss of so many cells and important energy producing agents can be helped. A recent study showed that exercise during treatment dramatically improved the energy levels of the patients, both physically and mentally.
As one may see from the above information of etiology, signs and symptoms, and potential complications of this disease, breast cancer is a serious disease that should not be taken lightly. In order to prevent complications, it is important for women to perform self exams, get regular mammograms, and maintain a healthy lifestyle, so that if the disease does occur there is optimal prognosis.
