Breast cancer

The female mammary gland is by the skin, the fiber organization, the mammary gland body and the fat composition, the breast cancer is occurs in the mammary gland gland epithelial tissue malignant tumor. 99% of breast cancers occur in women and only 1% in men.
Mammary gland is not an important organ to maintain human life activities. But because breast cancer cells have lost their normal cell identity, they are loosely connected and tend to fall off. Once cancer cells are shed, free cancer cells can spread throughout the body with blood or lymph, forming metastases and endangering life. At present, breast cancer has become a common tumor threatening women's physical and mental health.
The global incidence of breast cancer has been on the rise since the late 1970s. One in eight American women will develop breast cancer in her lifetime. China is not a country with high incidence of breast cancer, but it should not be optimistic. In recent years, the growth rate of breast cancer incidence in China is 1 ~ 2 percentage points higher than that in countries with high incidence. According to the data on the incidence of breast cancer in 2009 released by the national cancer center and the disease prevention and control bureau of the ministry of health in 2012, the incidence of breast cancer in tumor registries nationwide ranks the first among female malignant tumors. The total incidence (crude rate) of female breast cancer in China is 42.55/100,000, that in urban areas is 51.91/100,000, and that in rural areas is 23.12/100,000.
Breast cancer has become an important public health problem. The global mortality rate of breast cancer has been decreasing since the 1990s. The reasons are as follows: firstly, the development of breast cancer screening increased the proportion of early cases; Second, the development of comprehensive treatment for breast cancer has improved the curative effect. Breast cancer has become one of the most effective solid tumors.

The cause of
The cause of breast cancer is not completely clear, the study found that the incidence of breast cancer has a certain regularity, with breast cancer risk factors of women prone to breast cancer. The so-called high-risk factors refer to various risk factors related to the incidence of breast cancer, and the risk factors that most breast cancer patients have are called high-risk factors of breast cancer. According to the annual report of tumor registration in China, the age specific incidence of breast cancer in women is lower at the age of 0 ~ 24 years old, gradually increases after 25 years old, reaches a peak in the group of 50 ~ 54 years old, and gradually decreases after 55 years old. A family history of breast cancer is a risk factor for the development of breast cancer. In recent years, it has been found that breast gland density is also a risk factor for breast cancer. Risk factors for breast cancer include early menarche (<12 years old) and late menopause (>55 years old). Unmarried, childless, late childbearing, not breastfeeding; Breast benign disease not timely diagnosis and treatment; By the hospital biopsy (biopsy) confirmed with atypical hyperplasia of breast; Exposure of the chest to excessive doses of radiation; Long-term use of exogenous estrogen; Postmenopausal obesity; Long-term excessive drinking; And carry a gene mutation linked to breast cancer. What needs to be explained is that a large number of studies have been carried out on the susceptibility genes of breast cancer in European and American countries. Currently, brca-1 and brca-2 are known, as well as p53 and PTEN. Breast cancer related to these gene mutations is called hereditary breast cancer, accounting for 5% ~ 10% of all breast cancers. Women with the above risk factors do not necessarily have breast cancer, can only say that their risk of breast cancer is higher than normal, the incidence of breast cancer in Chinese women is still low.

Clinical manifestations of
Early breast cancer often does not have typical symptoms and signs, is not easy to pay attention to, often found through physical examination or breast cancer screening. Here are the typical signs of breast cancer.
A breast lump
Breast mass is the first diagnosis for 80% of breast cancer patients. The patient often discovers mammary gland bump unintentionally, it is simple hair more, qualitative hard, brim is irregular, the surface is owed smooth. Most breast cancers are painless masses, with only a few accompanied by varying degrees of dull or tingling pain.

Nipple discharge
Non-pregnancy from the nipple out of the blood, serous fluid, milk, pus, or stop breastfeeding more than half a year still have milk outflow, known as nipple overflow. There are many causes of nipple discharge, including intraductal papilloma, breast hyperplasia, ductectasia, and breast cancer. Unilateral monoporous hemorrhagic effusion should be further examined, if accompanied by breast masses should be more attention.

Skin changes
Breast cancer can cause skin changes to appear a variety of signs, the most common is the tumor invaded the Cooper ligament connecting the skin of the breast and the deep chest muscle fascia, make it shorten and lose elasticity, pull the skin of the corresponding part, appear "dimple sign", namely the skin of the breast appears a small depression, like a small dimple. If cancer cell blocked lymphatic canal, can appear "tangerine skin appearance changes", namely mammary gland skin appears a lot of small dot shape sunken, resemble tangerine skin same. In advanced stage of breast cancer, cancer cells infiltrate into the skin along lymphatic vessels, glandular ducts or fibrous tissue and grow, forming scattered hard nodules in the skin around the main cancer focus, which are called "skin satellite nodules".

Abnormal nipple and areola
The tumor is located in or near the depth of the nipple and may cause nipple retraction. The tumor is farther from the nipple, the large ducts in the mammary gland is invaded and shortened, can also cause the nipple retraction or elevation. Papillary eczematoid carcinoma, that is, Paget's disease of the breast, manifested as the nipple skin itching, erosion, ulceration, scab, desquamation, accompanied by burning pain, so that the nipple retraction.

Axillary lymphadenoma
More than one-third of breast cancer patients admitted to major hospitals have axillary lymph node metastasis. At the initial stage, ipsilateral axillary lymph node enlargement may occur. As the disease progresses, the lymph nodes gradually fuse and adhere to the skin and surrounding tissues. Metastatic lymph nodes may be felt in the supraclavicular and contralateral axillary regions in later stages.