Like cancer in other parts of the body, breast cancer involves the growth and multiplication of abnormal cells.

When the normal process of cell growth is disrupted, new cells begin form when the body doesn’t need them and old or damaged cells fail to die when they should. These abnormal cells often form a mass of tissue called a lump or tumor. These growths can be benign (not dangerous to a patient’s health) or malignant (in need of immediate treatment).

When malignant cells form in the tissues of the breast, they can invade the surrounding tissue or spread to other areas of the body. With early detection and treatment, however, most breast cancer patients continue to lead a normal life.

Breast cancers may be either hormone positive or hormone negative, meaning that some tumors are fueled by the body’s production of estrogen or progesterone (hormone positive), while others do not.

Breast cancer spreads when the cancer cells show up in other parts of the body or when breast cancer cells travel to other organs through the blood vessels and/or lymph vessels. This is called metastasis.

Breast cancer most often spreads to the lymph nodes under the arm (axillary nodes), neck (cervical nodes), under the chest bones (internal mammary nodes), or just above the collar bone (supraclavicular nodes).

When it spreads throughout the system, it can appear in the bones, lungs, and liver. Less often, breast cancer may affect the brain.

Breast cancer can also recur (come back after treatment), appearing locally in the skin, in the same breast (if it was not removed as part of treatment), in other tissues of the chest, or elsewhere in the body.

A simple self-exam helps patients to keep track of any changes in the breast. Among the things to look for—though not necessarily signs of cancer—are:

• Nipple tenderness
• Any nipple discharge
• A lump or thickening in or near the breast or in the underarm area
• A lump in the breast (not all lumps are cancerous but should be evaluated by a physician)
• An unusual change in the size or shape of the breast
• An usual swelling of the breast (especially if on one side only)
• Shrinkage of the breast (especially if on one side only)
• A new asymmetry of the breasts
• A nipple that has turned slightly inward or become inverted
• Scaly, red or swollen skin on the breast, areola, or nipple
• Ridges, dimpling or pitting in the breast, resembling the skin of an orange

perations to treat breast cancer may include the following:

Breast-conserving surgery: This approach removes the cancer while leaving as much breast tissue as possible intact.  This includes lumpectomy (removal of the lump with some surrounding tissue at the margin of the tumor), quadrantectomy (removal of one quarter, or quadrant, of the breast), and segmental mastectomy (removal of the cancer as well as some of the breast tissue around the tumor and the lining over the chest muscles below the tumor).

Modified radical mastectomy: In this operation, the surgeon removes the breast, most or all of the lymph nodes under the arm, and the lining over the chest muscles.  In some cases, part of the chest wall muscles will be removed as well.  This may be followed by reconstructive surgery to reshape the breast.

Total mastectomy: This surgery, also called simple mastectomy, removes the entire breast.

Lymph node removal: Following surgery, the patient’s lymph nodes may be removed and a sample of tissue taken, to check if the cancer has spread. In what is called a regional lymph node dissection, some of the lymph nodes in the tumor area are removed. In a radical lymph node dissection, most or all of the lymph nodes in the tumor area are removed. This procedure is also called a lymphadenectomy. A common side-effect of breast cancer surgery is lymphedema, swelling in the arms, hands, fingers, shoulders or chest, caused by fluid retention in the body.   Columbia surgeons have developed innovative protocols to prevent lymphedema following surgery for breast cancer.

When a lump is found, a needle biopsy can be performed in the physician’s office. A local anesthetic is injected into the breast, and light suction is applied through a hollow needle inserted into the lump to remove a sample of tissue or fluid. Disappearance of the lump after fluid is withdrawn usually indicates a benign cyst. Nevertheless, the fluid is sent to a laboratory for analysis. If no abnormal cells are found, no further tests are required.

In some cases, a surgical biopsy may be necessary. This procedure entails removing the lump and small amounts of surrounding tissues for laboratory analysis. A surgical biopsy usually is done in a hospital (often as out-patient surgery) using either local or general anesthesia. About 80 percent of these biopsies show no cancerous cells.

Additional Tests

When a tumor is found, it is tested to determine whether it is hormone dependent (estrogen- or progesterone-receptor positive). Additional tests are sometimes performed to measure the rate at which tumor cells are dividing (DNA flow cytometry) and to detect presence of abnormal genes such as one called Her 2/Neu.

Once the tumor has been identified, breast cancer will be classified according to its stage of growth. This will help determine the best possible treatment.

• Stage 0 (early stage): Includes findings of DCIS or Paget’s disease, but no actual tumor.
• Stage I (early stage): Tumor no more than 2 cm across, with no spread to lymph nodes.
• Stage II (early stage): Tumor 2 to 5 cm across, and cancer has spread to underarm lymph nodes.
• Stage IIA: Tumor less than 2 cm with lymph node involvement, or cancer between 2 and 5 cm with no lymph node involvement.
• Stage IIB: Tumor larger than 2 cm with lymph node involvement.
• Stage III: Also called locally advanced cancer, tumor larger than 5 cm, with extensive cancer in underarm lymph nodes, or that has spread to other lymph node areas or tissues near the breast (such as above or below the clavicle).
• Stage IIIA: Tumor larger than 5 cm with involvement of underarm lymph nodes. Any tumors fitting the description above.
• Stage IIIB: As in IIIA, and associated with chest wall or skin involvement, or with spread to lymph node above the clavicle.
• Stage IV: Cancer has spread to another organ in the body (also called metastatic cancer).