Breast Cancer (Facts, Stages) (cont.)

Medical Author:
Medical Editor:

What causes breast cancer?

Breast cancer, like all cancers, is caused when changes within a cell cause it to acquire the ability to grow in an uncontrolled way. Normal mechanisms fail to check the growth of cells, and a population of malignant cells arises that has the capability to invade normal tissues and spread within the body. Cancers likely arise due to a series of mutations with cellular genetic material, and there is no one risk factor that is exclusively responsible for causing breast cancer. As with other cancers, a combination of genetic and environmental influences are likely involved to cause breast cancers.

What are the different types of breast cancer?

Breast cancer can be described as invasive or in situ. Invasive breast cancers are tumors that have spread beyond the ducts or lobules of the breast and have begun to invade normal tissues.

In situ breast cancers -- ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS) -- are considered to be noninvasive forms of breast cancer. In these conditions, abnormalities in the cells have caused proliferation of atypical cells, but these cells have not spread beyond the ducts or lobules of the breast.

DCIS is currently an area of controversy in the breast cancer field. The risk of DCIS is that a few of the abnormal cells may ultimately become invasive cancer cells. However, many cases of DCIS will never become invasive, and after excision of the abnormal areas, most cases of DCIS do not recur. However, there remains the possibility that simple excision of DCIS is not sufficient to prevent recurrence in some women, so additional treatment is often given. Currently, studies are under way in an attempt to identify which cases of DCIS are most likely to become invasive and which cases will follow a more indolent course.

Among invasive breast cancers, about 70% arise in cells of the ducts and are known as invasive ductal carcinomas. Another 10% arise in the milk glands or lobules and are termed invasive lobular carcinoma. The remaining breast cancers are made up of less common types of cancer, including Paget's disease of the nipple, a type of cancer that affects cells beneath the nipple. Inflammatory breast cancer (IBC) is an uncommon and very aggressive kind of cancer that makes up 1%-5% of breast cancers. In inflammatory breast cancer, the cancer cells block lymph vessels in the skin of the breast. The breast often appears swollen and red, or "inflamed." Combinations of different cancer types are also possible.

Medically Reviewed by a Doctor on 9/29/2014

Patient Comments

Viewers share their comments

Breast Cancer - Symptoms Question: What symptoms did you experience when you developed breast cancer?
Breast Cancer - Stages Question: What stage was your breast cancer when you were diagnosed?
Breast Cancer - Type Question: What type of breast cancer do you have?
Breast Cancer - Treatment Question: What kind of treatment did you have for breast cancer?
Breast Cancer - Survival Rate Question: What is the prognosis for your breast cancer?
Breast Cancer - Diagnosis Question: How was your breast cancer detected?