There are several different types of breast surgery that are each performed for different reasons. Some of the options include:

Incisional Biopsy
This type of biopsy is used to remove tissue when a solid mass is present in the breast. Only part of the entire mass is removed from the breast through a one to two inch incision. This tissue is then tested to determine if the mass is benign (non-cancerous) or malignant (cancerous). This procedure is done under local anesthesia.
Excisional Biopsy
An excisional biopsy is used to remove the entire mass or lump. These are typically performed when a lump is small.
Mammary Duct Excision
Since most breast cancers begin in the mammary ducts, excision is used to remove one or both ducts for examination. This is performed when a patient reports nipple discharge. It is the only way to determine if the discharge is benign, or caused by invasive or non-invasive cancer, ductal hyperplasia, duct ectasia, or another problem. Mammary duct excision is sometimes performed during or after a biopsy or ductoscopy.
A lumpectomy, sometimes called an excision biopsy, is used to extract an entire cancerous lump from the breast. A small portion of healthy tissue surrounding the lump is also removed to ensure all traces of malignant tissue are gone. This procedure is typically recommended for patients with small, localized tumors. Doctors sometimes recommend a lymph node biopsy, as well as radiation treatment in conjunction with a lumpectomy.
Sentinel Lymph Node Biopsy
This lymph node is located under the arm and is the first to drain fluid from the breast. Many doctors believe it to be the first place malignant cells appear if and when they spread, and therefore, a good indicator for noting that cancer has not spread if they test clear. It is for this reason a sentinel lymph node biopsy may be performed at the same time as the breast biopsy or lumpectomy.

To perform this procedure, a dye or radioactive tracer is injected into the breast tumor. The dye or tracer is then tracked as it moves into the lymph node through drainage. This allows the surgeon to then remove that specific node and test it for cancer cells. If results are negative, no further action is needed. A biopsy of the lymph nodes is performed if results are positive on the tested node.

Axillary Lymph Node Dissection
This procedure is used to determine if cancer has spread beyond the breast. It can be performed at the same time as a breast or sentinel node biopsy, following positive results from a biopsy, or during a mastectomy. General anesthesia is administered and an incision is made under the arm. A small amount of fat containing a cluster of lymph nodes is removed and then the incision is closed with stitches. Side effects of this procedure include swelling or numbness, or limited movement in the arm and shoulder.
Modified Radical Mastectomy
This is the most common type of mastectomy. It is the surgical removal of the breast, nipple, areola, lining of the chest muscle, and some or all of the axillary lymph nodes. In some cases, a portion of the patient’s chest wall muscle is also removed. The procedure ensures the cancerous tumor is completely excised, as well as any breast or lymph tissue affected. It also reduces the risk of recurrence. The procedure is performed under general anesthesia. Some patients choose to undergo simultaneous breast reconstruction.