What Is Breast Cancer?
Breast cancer is the abnormal growth of cells in the breast.
The body has genes that control the way our cells divide and grow. The body’s cells divide, grow and die. There are times when the genes do not work as they should. This is called a mutation, or genetic error, and the cells grow out of control. They divide, grow, and grow and grow. These mutations can be spontaneous (they just happen) or they may be inherited (you were born with it). BRCA1 and BRCA2 have been identified as gene mutations and increase the risk of developing breast cancer during a lifetime. When the cells divide and grow and keep dividing and growing they form growths. Growths can be a mass or a lump and they are called tumors. Tumors can be benign (non cancerous) or malignant (cancerous).
Benign tumors are not cancerous. The cells of a benign tumor do not spread to other tissues. Sometimes benign tumors are removed because they may cause other health risks but they typically do not reappear.
Malignant tumors are cancerous. The abnormal cells have continued to grow and divide without dying and these tumors may invade other tissues and spread to other parts of the body. When a malignant tumor forms in the breast it is called breast cancer.
Types of Breast Cancer
There are actually many different types of breast cancer. Breast cancer can be defined by many characteristics including where it occurs in the breast, the size of the tumor (if present), its spread, or other factors that influence how the cancer grows.
To determine a course of treatment, the doctor needs to know the extent or Stage of the disease. The stage is determined by the size of the tumor and whether the cancer has spread. Staging may involve additional tests or may be determined after the initial surgery.
The doctor may also order tests to determine if the cancer is Hormone receptor positive or HER2 positive.
The Hormone Receptor Test shows whether the cancer has certain hormone receptors - like estrogen and progesterone – that the tumor needs to grow.
The HER2 test shows whether the tissue has a protein called human epidermal growth factor receptor-2 (HER-2) or the HER2/neu gene. Having too much protein or too many copies of the gene in the tissue may increase the chance that the breast cancer will come back after treatment.
Stages of Breast Cancer
Stage 0 is carcinoma in situ. In Situ is latin for in place. Ductal and lobular carcinomas that have not spread outside the duct or lobule are called in situ cancers.
Lobular carcinoma in situ (LCIS): Abnormal cells are in the lobules (the milk producing glands) of the breast. LCIS seldom becomes invasive cancer but increases the risk of cancer developing in both breasts.
Ductal carcinoma in situ (DCIS): (also called intraductal carcinoma) Abnormal cells occur in the lining of the milk ducts in the breast and have not spread outside the duct or invaded nearby breast tissue.
Stage I is an early stage of invasive breast cancer. The tumor is no more than 2 centimeters across. Cancer cells have not spread beyond the breast
Stage II can include one of the following:
The tumor in the breast is no more than 2 cm. across. The cancer had spread to the lymph nodes under the arm.
The tumor is between 2 and 5 cm. The cancer may have spread to the lymph nodes under the arm.
The tumor is larger that 5 centimeters and the cancer has NOT spread to the lymph nodes under the arm.
Stage III may be a larger tumor but the cancer has not spread beyond the breast and nearby lymph nodes. This is called locally advanced cancer. There are various subcategories to stage III cancer depending on the size and spread and location of the spread.
Stage IV is distant metastatic breast cancer. The cancer has spread to other parts of the body.
Inflammatory breast cancer is a rare type of stage IIIB breast cancer. The breast may look red and swollen because cancer cells block the lymph vessels in the skin of the breast. Inflammatory breast cancer may also be indicated by an inverted nipple, sudden and unusual increase in breast size, a persistent itch or rash. IBC is rarely found with a routine mammogram or ultrasound unless a lump is present. A needle core biopsy, MRI or PET scan may aid in diagnosis.
Another rare type of breast cancer is Pagets Disease, a rare form of cancer that forms in the nipple. 95 percent of people with Paget disease also have an underlying breast cancer.