Breast cancer develops from cells in breast tissue that change over time. Early detection of breast changes by mammography or a manual exam are key to successful treatment of breast cancer. It is important to understand the types of breast tumors to direct treatment if a breast tumor occurs.
In Situ Tumors
"In situ" tumors are usually too small to be detectable by manual exam and do not present with any symptoms. Advances in mammography imaging technology allow for detection of these subtle changes in either the cells lining the milk duct of the breast or lobes of the ducts themselves. These early tumors are referred to as ductal carcinoma in situ (DCIS) and lobule carcinoma in situ (LCIS), respectively. According to the Mayo Clinic and UCSF Medical Center, these early, tumorigenic changes in breast tissue are not yet invasive but are considered dangerous, because they may develop into more aggressive, invasive forms of the cancer.
Invasive Ductal Tumors
As DCIS grows, tumors break through the wall of the milk duct and invade other tissues of the breast. At this stage, the tumor is referred to as "invasive." Invasive ductal tumors are the most common type of breast tumor and represent over 80 percent of invasive breast cancers. Like other tumors of the breast, invasive ductal tumors are more likely to occur in women more than 55 years old.
Invasive Lobular Tumors
Over time, LCIS tumors will grow and invade other tissues of the breast. According to the National Cancer Institute, only about 10 percent of invasive breast cancers are invasive lobular carcinoma. As these invasive tumors grow, cells from the tumor can find their way to the lymph node and other organs to metastasize to other organ systems. This type of invasive cancer can occur at any point in a woman's life but is most likely to occur after the age of 55.
Paget's Disease of the Nipple
Paget's disease of the nipple starts as a collection of tumor cells on or around the nipple. This cancer typically starts out affecting the nipple ducts and then spreads to the areola, resulting in redness or irritation of the nipple. According to the National Cancer Institute, this rare form of breast cancer makes up only about 5 percent of breast cancer cases, and 97 percent of patients with Paget's disease also have some other form of invasive breast cancer. Paget's disease can occur in men but is more likely to occur in women.
