Ductal carcinoma in situ (cancer confined to the milk ducts of the breast)

Lumpectomy (breast-conserving surgery to remove tumor and some surrounding tissue) or mastectomy

Lobular carcinoma in situ, classic (abnormal cells confined to the milk-producing glands of the breast)

Sometimes surgery to check for cancer

If no cancer is detected, observation plus regular examinations and mammograms

Rarely, bilateral mastectomy (removal of both breasts) to prevent invasive cancers

Lobular carcinoma in situ, pleomorphic (which, unlike the classic type, leads to invasive cancer)

Surgery to remove the abnormal area and some of the tissue around it

Stages I and II (early-stage) cancer

Lumpectomy, followed by radiation therapy

Mastectomy with or without breast reconstruction

Sometimes, neoadjuvant therapy (chemotherapy before surgery) to reduce tumor size and optimize the chances for breast-conserving surgery

Stage III (locally advanced) cancer (including inflammatory breast cancer)

Often, chemotherapy or sometimes hormone blockers before surgery to reduce tumor size

Lumpectomy or mastectomy, if the tumor is small enough to be completely removed

Usually, radiation therapy after surgery

Sometimes chemotherapy, hormone blockers, or both after surgery

Stage IV (metastatic) cancer or cancer that recurs

For estrogen receptor–positive tumors, hormone blockers or removal or suppression of ovaries

Chemotherapy

Radiation therapy for the following:

• Metastases to the brain

• Metastases that recur in the skin

• Metastases that occur in one area of bone and that cause symptoms