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Breast Cancer, Lumpectomy, and Partial Mastectomy

In breast cancer, lumpectomy (wide local excision) and partial mastectomy are breast-conserving operations in which the surgeon removes the tumor together with some normal breast tissue surrounding it. Breast-conserving procedures may be done with local anesthesia or under general anesthesia (being put to sleep) on an outpatient basis.

Women who have this type of breast cancer surgery usually:

  • Have a single breast cancer less than five centimeters in diameter
  • Have enough tissue so that removing surrounding tissue would not leave a misshapen breast
  • Are medically able to undergo surgery and follow-up radiation therapy

A lumpectomy followed by radiation therapy is often considered the standard therapy for women with breast cancer who meet these criteria. Large studies have shown similar survival rates for both breast conservation with radiation and removal of the whole breast, but a lumpectomy gives a better cosmetic result.

Women who aren't candidates for lumpectomy plus radiation include those who:

  • Have had radiation to the same breast for an earlier breast cancer
  • Are pregnant
  • Have multiple tumors in the breast
  • Have very large tumors, or locally advanced breast cancer
  • Have a tumor that makes it impossible to remove with an adequate margin

What Happens During a Lumpectomy or Partial Mastectomy

A lumpectomy to treat breast cancer is done under local or general anesthesia and usually takes one to two hours. Small metallic clips may be placed inside the breast to mark the area for the radiotherapist to treat. Lymph nodes are often examined at the same time as the breast tissue is removed, either by extending the incision to the armpit or by a separate small incision under the arm. Often, a blue dye or a small amount of radioactive material will be injected around the nipple area or in the breast tissue near the region of the tumor. The material moves to the lymph nodes and helps identify which lymph nodes need to be removed for testing (sentinel lymph node biopsy). The tissue that is removed from the breast is sent to the pathology lab where tests are done to identify the type of tumor, whether cancer has spread to the lymph nodes, and to assess the tumor for hormone sensitivity (estrogen and progesterone receptors). In addition, other specialized tests that determine prognosis and treatment, such as HER2 testing and genomic assays, may be performed. It may take several days to identify the type of tumor and receive the results of the specialized tests.

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