Breast Cancer Pathophysiology

Breast cancer is one of the most misunderstood and feared cancers in women today. While it is true that breast cancer is extremely common amongst the cancers modern women are likely to contract, there are also many misconceptions about the disease, partially due to the effectiveness of the awareness campaign that has been heralded in the media in recent decades. For example, very one common misconception about breast cancer is that it is the most deadly cancer for women. In actuality, skin cancer is the most common cancer in the United States for women. Breast cancer is only the second most common cause of cancer death after lung cancer for women. A woman who worries about breast cancer but does not quit smoking, for example, might be well-advised by a nurse to take measures to mitigate her chances of contracting that cancer, as well as cancer of the breast (Mending the myths about breast cancer, 2008, Eli Lilly).

Some of the fears of women are valid, other of the fears lead to poor health care practices. The relatively new nature of the anti-breast cancer, pro-self-exam campaign means that young women often overestimate and older women underestimate their risk level (Breast cancer facts and fiction for healthcare professionals, 2008, Elli Lilly). In reality, besides being a woman, age is one of the greatest contributing factors to breast cancer -- it is far more likely to occur in childless, post-menopausal women over the age of fifty, for example (Breast cancer facts and fiction for healthcare professionals, 2008, Elli Lilly).

Another common misconception is that 'if my mother got breast cancer, I will get breast cancer,' or, conversely, that if no one in the family has breast cancer, 'I don't need to worry.' Other myths are that breast size or density plays a significant role in the likelihood of contracting the cancer. The reality is that breast cancer is a disease with both genetic and environmental causes. "85% of women with breast cancer do not have a family history of breast cancer" (Mending the myths about breast cancer, 2008, Eli Lilly). Approximately 15% to 20% of all breast cancers "have a clear familial link. Approximately 5% to 10% of all breast cancers are due to a mutation in a single, heritable gene that confers susceptibility to cancer. Inherited gene mutations (BRCA1 and BRCA2) are associated with early onset breast cancer. Two of the major cancer-susceptibility genes are the BRCA1 and BRCA2 tumor-suppressor genes" ("Genetics of breast cancer," 2008, Eli Lilly).However, most breast cancers (70% to 80%) result from sporadic mutations or occur by chance as a result of multiple gene mutations in a single cell. "Most breast cancers that occur in postmenopausal women are not associated with a hereditary syndrome and are estrogen-receptor positive (ER+).The growth of ER+ breast cancer cells appears to be influenced by endogenous estrogens. Women with ER+ breast cancer have a generally better prognosis than those who are ER-" (Hormone-Receptor Status and Breast Cancer, 2008, Eli Lilly). The role of estrogen is still being explored by cancer researchers today.

Clinical manifestations

Breast cancer occurs in two basic forms: in situ and in the form of an invasive cancer. While an in situ example of breast is confined to a particular area of the body, "invasive breast cancer may be localized, regional, or metastatic," and "occurs when malignant cells break through the basement membrane and first invade the fatty tissue, then spread to the lymphatics and bloodstream Approximately 211,000 new cases of invasive breast cancer and 41,000 deaths from breast…