Stage 0: Non-invasive ductal carcinoma in situ (DCIS)
=Surgery: Involves removing the abnormal tissue in the breast. Depending on much the cancer has spread within the milk ducts, surgery may be either mastectomy or lumpectomy.
=Radiation therapy. Women with DCIS are only treated with radiation therapy after a lumpectomy, not a mastectomy. Lumpectomy for DCIS is usually followed by radiation therapy to lower the risk of DCIS recurrence and invasive breast cancer.
Hormone therapy: It is recommended that women who are treated with lumpectomy plus radiation therapy for estrogen receptor-positive DCIS consider taking tamoxifen for five years. This drug works by preventing the cancer cells from getting the estrogen they need to grow. Tamoxifen can lower the risk of DCIS recurrence and invasive breast cancer. Tamoxifen is usually not recommended for women who have a mastectomy for DCIS.
Stage I: Early stage invasive breast cancer; has not spread outside breast.
Surgery: Lumpectomy, partial mastectomy, or mastectomy.
Radiation therapy: Usually given after surgery to lower the chance of recurrence.
Hormone therapy: Most doctors recommend hormone therapy with tamoxifen to women who have a hormone receptor–positive breast cancer.
Stage II: Still in early stages, but cancer has begun to grow and spread. Still confined to breast.
Surgery: Lumpectomy, partial mastectomy, or mastectomy.
Radiation therapy: Recommended for women who had surgery or who had large tumors (more than 5 cm) or cancer cells in the lymph nodes.
Hormone therapy: Recommended for women with hormone receptor–positive invasive breast cancer. May be started before surgery, but since it must continue for at least five years, it needs to be given after surgery too.
Chemotherapy: Usually recommended for women with invasive breast cancer whose tumor is hormone receptor-negative, and for women with hormone receptor-positive tumors who may also benefit from chemo and hormone therapy. May be given before or after surgery.
Targeted therapy: If the cancer is HER2 positive, HER2 targeted drugs are started with chemo. Both trastuzumab and pertuzumab may be used as a part of treatment before surgery. Trastuzumab is continued after surgery for one year.
Stage III: Locally advanced; cancer is invading surrounding tissues near breast.
Surgery: Usually mastectomy, but lumpectomy or partial mastectomy may be an option depending on invasiveness. Chemo and targeted therapy may be done first to shrink tumor.
Radiation therapy: May be given before or after surgery.
Hormone therapy: May be given before or after surgery.
Chemotherapy: Usually done before surgery.
Targeted therapy: For HER2-positive tumors, trastuzumab is also given before surgery (sometimes along with pertuzumab)
Stave IV: Metastatic; cancer has spread beyond the breast to other areas of the body.
Surgery or radiation may be helpful, but systemic therapy is the main treatment
Systemic therapy:
Hormone therapy: usually the first treatment for metastatic breast cancers that are hormone receptor-positive.
Chemotherapy: The first treatment for women with hormone receptor-negative tumors and who have life-threatening metastases. It is also used to treat breast cancers that no longer respond to hormone therapy. Chemotherapy also has a better response time than hormone therapy because it can shrink tumors faster.
Targeted therapy: Trastuzumab is only used to treat HER2-positive breast cancers.