Breast cancer is classified according to where the cancer originates. The Mayo Clinic explains that breast cancer can start in the ducts of the breast, the milk-producing lobules of the breast or, sometimes, the connective tissue that is in between the ducts and lobules. Understanding the type of cancer a patient has helps doctors determine which treatment is best.
Ductal Carcinoma In Situ (DCIS)
Ductal carcinoma in situ (DCIS) is listed by BreastCancer.org as the most common type of noninvasive breast cancer. Ductal carcinoma is a type of cancer that originates in the ducts of the breast; in situ means "in its original place." DCIS is called noninvasive, because it does not spread beyond the ducts of the breast. A patient with DCIS is at risk of developing more dangerous cancer later on in life, states BreastCancer.org.
Invasive Ductal Carcinoma (IDC)
According to the National Breast Cancer Foundation (NBCF), invasive ductal carcinoma (IDC) is the most common form of breast cancer, diagnosed in 78 percent of all invasive breast cancer cases. This cancer is invasive, which means that the cancer can grow into the tissue surrounding the ducts and affect other sites. IDC lesions can appear star-like (stellate) or round on mammograms.
Medullary Carcinoma
A medullary carcinoma is a mass with cells that resemble the gray matter (medulla) of the brain, describes the NBCF. The NBCF goes on to say that this type of cancer accounts for 15 percent of all breast cancer types and is seen most frequently in women in their 40s and 50s.
Infiltrating Lobular Carcinoma (ILC)
BreastCancer.org reports that 5 percent of all breast cancer diagnoses turn out to be infiltrating lobular carcinomas (ILCs). This type of cancer appears as a subtle thickening in the upper-outer quadrant of the breast. This cancer responds well to hormone therapy, suggests BreastCancer.org.
Tubular Carcinoma
Tubular carcinoma, reports the NBCF, makes up 2 percent of all breast cancers. The cells of this type of cancer form tube-like structures when viewed under a microscope. The NBCF says that tubular carcinoma has an excellent prognosis, with a 10-year survival rate of 95 percent.
Mucinous Carcinoma
Approximately 1 to 2 percent of all breast cancers are mucinous, or colloid, carcinomas, notes the NBCF. Mucinous carcinomas are characterized by cells that produce mucous. The NBCF says this type of cancer has a good prognosis.
Inflammatory Breast Cancer (IBC)
Inflammatory breast cancer (IBC) begins as a reddening and swelling of the breast tissue, says BreastCancer.org. Reddening and swelling are signs of inflammation. This is specific to IBC, because most types of breast cancer start as a distinct lump. IBC tends to grow and spread quickly. Prompt treatment is important, and modern medical techniques can control the disease.
