Breast cancer originates from abnormal, cancer-prone cells that develop in the breast tissue as a result of environmental, genetic and still unknown factors. Over time, cancerous cells proliferate in specific tissues of the breast and form a solid tumor mass. As the tumor mass grows, tumor cells may shed from the tumor to invade other tissues to take over vital organ systems. It is important to understand types of breast cancer to direct treatment and prevention programs.
In Situ Breast Cancer (DCIS and LCIS)
The earliest "in situ" stages of breast cancer are usually asymptomatic. Mammography has allowed the detection of early cellular changes in breast tissue which represent early, non-invasive stages of cancer. Such changes are referred to as "breast cancer in situ" and may develop into invasive cancer. According to the Mayo Clinic, two types of in situ breast cancer are ductal carcinoma (DCIS) and lobular carcinoma in situ (LCIS). Ductal carcinoma originates from the cells lining the milk duct. Lobular carcinoma cells line the milk lobule. LCIS is not considered to be actual breast cancer, but is taken as a warning sign of cells that may develop into invasive cancer.
Invasive Breast Cancer
After abnormal cells develop in the milk duct or lobule they can grow spread to neighboring tissue in the breast. Such tumors are found by mammogram or by touch during a manual breast exam. At this stage of the cancer, the size and staging of the tumor will be an important factor in determining options for intervention.
Metastatic Breast Cancer
After time, tumor cells may escape from large, invasive breast tumors and find their way to the lymphatic system or to other organs. According to the University of California at San Francisco, metastatic breast cancer develops months to years after an invasive tumor develops. Common site of metastasis include the bones, liver, lung and brain.
Inflammatory Breast Cancer
Locally advanced or inflammatory breast cancer is more rare than other cancers of the breast. This form of cancer is very dangerous and aggressive. Inflammatory breast cancer is often mistaken as an infection as it causes the breasts to feel warm and take on a red color and show wrinkles or hives.
