Good Research Paper About Breast Cancer
Overview of Cancer
Cancer is a multifactorial and very complex disease that affects various organ systems of the human body and afflicts millions of people worldwide. There are hundreds of specific cancer types and are usually grouped together by the tissue of origin. There is no single cause of cancer, although several risk factors may make a person more likely to develop this condition. Cancer may be caused by interplay among a multitude of exogenous carcinogens which may be physical, biological or chemical, and various endogenous biological processes within cells. Some characteristics of human cancers include rapid and unregulated cell proliferation, reduced cell death by apoptosis, immortalization, altered metabolism and cell/tissue differentiation, significant genomic instability, and possibly tissue invasion by metastasis (Schulz, 2005; Pecorino, 2012). This paper will discuss cancer of the breast.
Breast cancer is the most common type of cancer in the world, especially in adult females, and is one of the top leading causes of cancer mortality. It is more common in industrialized Western countries, with about one in nine women in the UK and the USA developing the disease within their lifetime. Various aspects of the “Western lifestyle” are said to be more favorable to the development of the disease. Breast cancer is more likely to occur in postmenopausal women (menopause often occurs between the ages of 45 and 55), but may affect younger women as well, especially those with a family history of the disease. It may also affect males, accounting for about 1% of all cases. The incidence of breast cancer is still rising worldwide, although mortality rates are kept at bay by earlier diagnosis and the increasing number and efficacy of treatment options (Schulz, 2005; Abdulkareem, 2013).
A lump or mass in the breast is the most common symptom of breast cancer. The patient may also experience swelling in a part or the entire breast, “dimpling” brought about by skin irritation, nipple or breast pain, retraction of the nipple (turning inward), redness, scaling or thickening of the skin, and nipple discharge (American Cancer Society [ACS], 2015).
There are various etiological or risk factors that affect the likelihood of a person to develop breast cancer. The foremost is age and sex, with females being more likely to develop the disease, and wherein breast cancer is very uncommon before the age of 20 years but the risk gradually increases with age, such that by the age of 90 years, about one fifth of all women are afflicted by the disease. This is probably influenced by exposure to hormones called estrogens, which are purported to have central roles in both the development and progression of breast cancer. Events that prolong or increase estrogen exposure such as earlier menarche, later menopause, and pregnancy, all increase the risk of breast cancer. Moreover, hormone replacement therapy and oral contraceptive use also increases exposure to estrogen and thus increase cancer risk (Schulz, 2005; Pecorino, 2012; ACS, 2015).
Diet also plays a large part in the development of breast cancer, as well as many other types of conditions. Diets high in fats and cholesterol, which is the precursor to many hormones such as estrogens, increase the risk of breast cancer while consumption of foods with high dietary fiber, vitamins, and minerals such as fresh fruits and vegetables reduces the risk of cancer. Obesity and lack of physical activity is also a risk factor because adipose (fat) cells produce estrogens from androgens, and exercise has been linked to interference with hormone levels. This is particularly important in post-menopausal women, whose primary sources of estrogens are fat cells. High alcohol intake has also been shown to increase breast cancer risk in a dose-dependent manner due to a still not fully understood association with estrogens. Other environmental factors such as radiation exposure and various exogenous carcinogens are also risk factors (Pecorino, 2012; Abdulkareem, 2013; ACS, 2015).
Finally, genetic factors significantly increase the risk of breast cancer. About 5% to 20% of all breast cancer cases are thought to be hereditary. The most significant of the associated genes are the tumor suppressing genes, BRCA1 and BRCA2, which prevent the abnormal growth of cells. Mutations that lead to the inactivation of these two genes increases breast cancer risk by up to 80%. The BRCA1 and BRCA2 proteins are implicated in various genetic controls such as DNA repair, checkpoint signaling, and prevention of chromosome breaks. As such, they are expressed in almost all tissues. Germ-line mutations in both BRCA1 and BRCA2 genes occur along the entire length of the genes. Most are frame-shift mutations caused by deletions and insertions. Nonsense mutations, splice-site mutations, and missense mutations (rare) may also occur. All these mutations cause the expressed proteins to become non-functional. Other gene mutations can also increase the risk of breast cancer, although they are not frequently observed in breast cancer cases: ATM, implicated in DNA damage repair; TP53, control of DNA repair and genomic integrity; CHK1 and CHK2: checkpoint kinases of the cell cycle; PTEN: cell growth regulation; and CDH1, STK11, and PALB2: mutations associated with increased breast cancer risk (Schulz, 2005; ACS, 2015).
Diagnosis and Treatment
As with many other diseases, diagnosis of breast cancer begins with extensive medical history taking and a physical exam with a thorough examination of the breasts. Most often imaging tests are required to elicit details such as the tumor’s size and location, as well as to locate cancer cells if metastasized, and which tissues are affected. These imaging tests include mammogram, chest X-ray, ultrasound (sonography), Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET) scan, and CT scan. A biopsy of the mass is often done to confirm diagnosis and staging tests are done to determine the optimal treatment plan (Price, Sikola, and Illidge, 2008; ACS, 2015).
Breast cancer may be treated by surgery, radiation, chemotherapy, hormone therapy, bone-directed therapy, and targeted therapy. These options are not mutually exclusive, and efficacy of managing breast cancer may be increased using multiple treatment types. When masses or tumors are present on the breast, breast-conserving surgery, lymph node surgery, and/or mastectomy is often performed. Radiation is often given to increase the chance of cancer remission after breast-conserving surgery, in patients with large tumors, and in patients with cancer in the lymph nodes. Chemotherapy is often recommended for patients with metastasized breast cancer, but it may also be performed before surgery to shrink tumors or after surgery to remove remaining cancer cells. Hormone therapy is usually used as an adjuvant to other treatments in order to prevent cancer from coming back by suppressing estrogen levels. Targeted therapy is a more recent treatment plan that utilizes biologics that target specific molecular pathways and thus have fewer adverse side effects (Sledge et al., 2014; ACS, 2015).
Researchers are still trying to further understand the mechanisms of breast cancer, as well as to locate possible cures or at least better treatment options. Studies are trying to uncover the link between lifestyle factors (e.g. exercise, weight, diet, etc.), genetics, and environmental conditions and breast cancer risk. Research on improving genetic testing especially for the BRCA genes is also underway. The National Institute of Environmental Health Sciences (NIEHS) has funded a large, long-term study to determine the causes of breast cancer, which involves 50,000 women with sisters afflicted with the disease. Preventive measures, better diagnostic test and technology, as well as novel and improved treatment options with increased focus on molecular medicine, are also being researched (ACS, 2015; Pecorino, 2012). Finding a cure to cancer still remains the ultimate goal for various researchers.
Abdulkareem, I. H. (2013). A Review on Aetio-Pathogenesis of Breast Cancer. Journal of Genetic Syndromes & Gene Therapy 4(5): 1-4.
American Cancer Society (2015). Breast Cancer. ACS. Retrieved from http://www.cancer.org/breastcancer
Pecorino, L. (2012). Molecular Biology of Cancer: Mechanisms, Targets, and Therapeutics (3rd Ed.). UK: Oxford University Press.
Price, P., Sikola, K., & Illidge, T. (2008). Treatment of Cancer (5th Ed.). USA: CRC Press.
Schulz, W. A. (2005). Molecular Biology of Human Cancers. Netherlands: Springer Science.
Sledge, G. W., Mamounas, E. P., Hortobagyi, G. N. et al. (2014). Past, Present, and Future Challenges in Breast Cancer Treatment. Journal of Clinical Oncology 32(19): 1979-1986.