How is Breast Cancer Treated?

This is the eighth page in the Understanding Breast Cancer Guide. This guide was developed by the HealthTree Education Team and was last updated and reviewed on May 18, 2026.

The treatment for breast cancer depends on several factors, including the stage of the cancer, where in the breast the tumor is located, the biological features of the tumor (hormone receptor status, HER2 status, and grade), your overall health, and whether this is a new diagnosis or a recurrence.

Treatment often involves a combination of therapies. It is important to discuss all of your treatment options with your care team to make the best decision for your unique situation. Getting a second opinion from another oncologist is normal and encouraged.

Surgery for breast cancer

Surgery is the primary treatment for most early-stage breast cancers and is a key part of treatment for many locally advanced cases. The type of surgery depends on the size and location of the tumor, the stage of the cancer, and patient preference:

Breast-conserving surgery (lumpectomy or partial mastectomy)

The surgeon removes the tumor and a margin of surrounding healthy tissue, while preserving as much of the breast as possible. This is also called a "wide local excision." Lumpectomy is usually followed by radiation therapy to treat any remaining cancer cells in the breast.

Mastectomy 

The surgeon removes the entire breast. There are several types of mastectomy:

• Simple (total) mastectomy. Removes the breast tissue, nipple, and areola, but not the lymph nodes.
• Modified radical mastectomy. Removes the entire breast and some of the axillary lymph nodes.
• Skin-sparing or nipple-sparing mastectomy. Removes the breast tissue while preserving the breast skin and/or nipple, often performed when immediate breast reconstruction is planned.
• Bilateral mastectomy. Removal of both breasts, sometimes chosen for risk reduction in high-risk women.

Lymph node surgery 

• Sentinel lymph node biopsy (SLNB). The surgeon removes one or a few lymph nodes (the "sentinel" nodes) to check if cancer has spread. If the sentinel nodes are negative, no more lymph nodes need to be removed.
• Axillary lymph node dissection (ALND). The surgeon removes multiple lymph nodes from the armpit if cancer has spread to the lymph nodes.

Breast reconstruction

Many women choose to have breast reconstruction after mastectomy, either at the time of the mastectomy or later. Reconstruction can use implants or the patient's own tissue (flap procedures).

Radiation therapy for breast cancer

Radiation therapy uses high-energy X-rays to destroy cancer cells. It is commonly used after breast-conserving surgery and sometimes after mastectomy. Radiation may be given:

• After lumpectomy (whole breast radiation). To treat any remaining cancer cells in the breast.
• After mastectomy (post-mastectomy radiation therapy, or PMRT). To treat the chest wall or lymph nodes when there is a higher risk of recurrence.
• To relieve symptoms in advanced disease (palliative radiation). For example, to treat painful bone metastases.

Chemotherapy for breast cancer

Chemotherapy uses drugs to kill cancer cells throughout the body. Common chemotherapy drugs used in breast cancer include:

• Anthracyclines, such as doxorubicin (Adriamycin) and epirubicin
• Taxanes, such as paclitaxel (Taxol) and docetaxel (Taxotere)
• Cyclophosphamide
• Carboplatin (Paraplatin)
• Capecitabine

Chemotherapy may be given:

• Before surgery which may allow for breast-conserving surgery and helps assess how the cancer responds to treatment. Chemotherapy given before surgery is called neoadjuvant chemotherapy.
• After surgery to reduce the risk of recurrence by treating any cancer cells that may have spread. Chemotherapy given after surgery is called adjuvant chemotherapy.
• As the main treatment for metastatic disease which is often combined with targeted therapy.

Hormone therapy (endocrine therapy) for breast cancer

Hormone therapy is used to treat hormone receptor (HR)-positive breast cancers. HR+ breast cancer can be estrogen receptor-positive (ER+) and/or progesterone receptor-positive (PR+). 

Hormone therapy works by lowering hormone levels in the body or by blocking estrogen or progesterone from reaching cancer cells. This is one of the most effective treatments for HR+ breast cancer. 

Types of hormone therapy include:

• Tamoxifen. Blocks estrogen receptors on breast cancer cells. Used in pre- and post-menopausal women.
• Aromatase inhibitors (AIs). Reduce the amount of estrogen made in the body. Examples include anastrozole (Arimidex), letrozole (Femara), and exemestane (Aromasin). Used primarily in post-menopausal women.
• Ovarian suppression or ablation. Reduces estrogen production in pre-menopausal women by suppressing the ovaries, using medication or surgery. Examples of medications used for ovarian suppression include goserelin (Zoladex) or leuprolide (Lupron).
• Fulvestrant (Faslodex). Blocks and degrades estrogen receptors. Used for metastatic HR+ breast cancer.

Targeted therapy for breast cancer

Targeted therapies are drugs that attack specific proteins or pathways on cancer cells. They are used based on the biological features of the cancer:

HER2-targeted therapies

These treatments are used for HER2-positive (HER2+) breast cancers:

• Trastuzumab (Herceptin). A monoclonal antibody that targets HER2. A standard component of treatment for HER2-+ breast cancer.
• Pertuzumab (Perjeta). Used in combination with trastuzumab for HER2-+ breast cancer.
  Ado-trastuzumab emtansine (Kadcyla, T-DM1). An antibody-drug conjugate that combines trastuzumab with a chemotherapy drug.
• Trastuzumab deruxtecan (Enhertu, T-DXd). A newer antibody-drug conjugate used for HER2-+ and HER2-low metastatic breast cancer. HER2-low refers to tumors that have small amounts of the HER2 protein but do not meet the threshold to be classified as HER2-+. This is a relatively new classification that has expanded the number of patients who many benefit from HER2-targered treatment.
• Lapatinib (Tykerb), neratinib (Nerlynx), tucatinib (Tukysa). Small molecule inhibitors that block HER2 signaling.

CDK4/6 inhibitors

Used for hormone receptor-positive, HER2-negative metastatic breast cancer, often in combination with hormone therapy:

• Palbociclib (Ibrance)
• Ribociclib (Kisqali)
• Abemaciclib (Verzenio)

PI3K/AKT/mTOR pathway inhibitors

• Alpelisib (Piqray). A PI3K inhibitor used with fulvestrant for hormone receptor-positive, HER2-negative, PIK3CA-mutated metastatic breast cancer.
• Everolimus (Afinitor). An mTOR inhibitor used in combination with exemestane for metastatic hormone receptor-positive disease.
• Capivasertib (Truqap). An AKT inhibitor used with fulvestrant for certain metastatic hormone receptor-positive cancers.

PARP inhibitors

Used for people with BRCA1 or BRCA2 mutations and metastatic breast cancer:

• Olaparib (Lynparza)
• Talazoparib (Talzenna)

Immunotherapy for breast cancer

Immunotherapy helps your immune system find and destroy cancer cells.

Checkpoint inhibitors are the main type of immunotherapy used in breast cancer. They are currently most effective for triple-negative breast cancer (TNBC) that is PD-L1 positive.

• Pembrolizumab (Keytruda) is approved in combination with chemotherapy for metastatic TNBC that is PD-L1 positive, and as neoadjuvant and adjuvant treatment for early-stage high-risk TNBC.
• Atezolizumab (Tecentriq) was previously used for TNBC but has had its breast cancer indication withdrawn in the United States.

Antibody-drug conjugates (ADCs)

ADCs are a newer type of targeted therapy that combines an antibody with a chemotherapy drug. They deliver chemotherapy directly to cancer cells. In addition to the HER2-targeted ADCs listed above, sacituzumab govitecan (Trodelvy) is an ADC approved for metastatic TNBC and HR+, HER2-negative metastatic breast cancer.

Treating metastatic breast cancer

For breast cancer that has spread to other organs, treatment is typically focused on controlling the cancer and extending life while maintaining quality of life. In rare cases where only a small number of metastases are present, more aggressive local treatment may be considered. The choice of treatment depends on the subtype of breast cancer, prior treatments, and individual patient factors after treatment

Supportive and palliative care for breast cancer

Treating the symptoms of cancer and side effects of treatment is called supportive and palliative care. This is an important part of cancer treatment at every stage, not just at the end of life. Palliative care can include:

• Pain management
• Management of treatment-related side effects (such as nausea, fatigue, neuropathy, and hot flashes)
• Lymphedema management if lymph nodes were removed or treated with radiation
• Nutritional support from a registered dietitian
• Physical and occupational therapy
• Mental health support and counseling

There is a common misconception that palliative care is only given at the end of life. Palliative and supportive care can be given at any time during cancer treatment.

Follow-up care after treatment

After breast cancer treatment ends, regular follow-up appointments are essential to watch for signs of recurrence and monitor your long-term health. This typically includes annual mammograms, physical exams, and monitoring for treatment-related side effects. People on hormone therapy will have regular check-ins throughout their treatment.