Breast Cancer Treatments

From the latest targeted therapies to the most innovative approaches emerging through clinical trials, Providence leverages the full power of today’s most advanced, evidence-based therapies to treat breast cancer. Your personalized treatment plan may include any or all of the following:

  • Surgery
  • Radiation therapy
  • Chemotherapy
  • Hormone therapy (endocrine therapy)
  • Targeted therapy
  • Clinical trials
  • Supportive services


There are several options for removing cancer surgically, including removing the entire breast (mastectomy) or just the tumor (lumpectomy or oncoplasty). Your breast surgeon will explain the options and help you decide which approach is best for your cancer, based on its size and location and your medical history. 

  • Lumpectomy: Also called breast-conserving surgery, this operation removes only the tumor, as well as a small “margin” of surrounding tissue to make sure no cancer cells are left behind. Lumpectomy is usually followed by radiation therapy to prevent recurrence near the site of the original cancer. It is often recommended for smaller, early-stage breast cancers, since it is a less-extensive surgery and preserves most of the breast. When paired with radiation, lumpectomy has the same survival rate as mastectomy in people who are candidates for both procedures.
  • Oncoplasty: After lumpectomy, the appearance of the breast is sometimes affected by the cavity left behind when the lump was removed. Oncoplasty is a new option that removes the tumor and preserves the breast’s appearance in a single procedure. Surgeons completely remove the cancerous mass and then reshape the remaining breast tissue, without implants, to fill the gap left by the extracted tumor.
  • Mastectomy: This surgery removes the entire breast, including all of the breast tissue and, in some cases, nearby tissues. Mastectomy is often recommended when there is a large tumor or when the cancer affects more than one area of the breast. Radiation therapy may not be needed after a mastectomy, but it’s sometimes recommended if there are concerns about cancer cells that might remain in the area.
  • Sentinel node biopsy: The "sentinel node" is the first lymph node draining from a breast tumor. If cancer spreads into the lymph nodes, the sentinel node is the first and most likely node to be affected. In a sentinel node biopsy, the surgeon removes this node and looks for cancer cells. If there aren’t any, then no further lymph node surgery is needed. If cancer cells are found in the sentinel node, then more lymph nodes may need to be removed to check for further cancer spread.
  • Reconstructive surgery: Reconstructive surgery is an option for restoring the appearance of the breast after cancer surgery, either with implants or with tissue taken from another part of your body. Sometimes this can be done right after your cancer surgery, sometimes it’s done later, and sometimes it’s done in stages. Be sure to consult with a plastic surgeon before your breast cancer surgery if you might be considering reconstruction.

Radiation therapy 

Radiation therapy is an effective way to destroy cancer cells and reduce cancer recurrence. Radiation is carefully directed to reach cancer cells with as little harm as possible to nearby healthy tissues. This therapy is usually given after breast cancer surgery, to eliminate any cancer cells left behind, but in some cases, it is used earlier to shrink tumors before surgery.

Providence’s radiation oncologists offer expertise in the most advanced radiation therapies, including these:

  • External beam radiation therapy (EBRT): the most common type of radiation therapy for breast cancer, EBRT uses a high-tech X-ray machine to deliver radiation to the cancer site.
  • Intraoperative radiation therapy (IORT): this treatment takes place in the operating room, right after surgery, using sophisticated equipment to apply a single, large dose of radiation directly to the tumor site. Providence St. Joseph was the first hospital in Orange County to offer IORT.
  • Intensity-modulated radiotherapy (IMRT): this technology delivers radiation very precisely to the tumor area, allowing the intensity of the beams to be adjusted for specific areas and reducing the effects on healthy tissues.
  • Brachytherapy: this type of therapy delivers radiation from a device implanted inside the breast, rather than from a machine outside the breast.


Unlike radiation, which focuses on the area where your cancer occurred, chemotherapy is “systemic,” which means that it travels throughout your body, looking for stray cancer cells anywhere that they might have spread. 

Chemo involves taking anti-cancer drugs, either intravenously or as pills, to kill cancer cells. It might be used after surgery (“adjuvant” therapy means after surgery) to reduce the risk of breast cancer returning; before surgery (“neoadjuvant” therapy means before surgery) to shrink a tumor and make it easier to remove; or as the main treatment to manage advanced breast cancer. The specific chemotherapy regimen that your medical oncologist prescribes for you will depend on the type and stage of your cancer and your general health.

Hormone therapy (endocrine therapy)

About two out of three breast cancers are fueled by female hormones. We describe these cancers as estrogen-receptor (ER) positive or progesterone-receptor (PR) positive. It means that the cancer cells have receptors on them that react to these hormones in a way that encourages the cancer to grow and spread. 

Hormone therapy, also called endocrine therapy, interferes with this reaction, either by lowering estrogen levels or by blocking the receptors from being affected by the hormones. It is usually taken as a pill for at least five to 10 years to reduce the risk of cancer coming back. It also may be used to treat cancer that has returned or spread.

Targeted therapy

Like chemotherapy, targeted therapy is systemic, traveling through the bloodstream to find cancer wherever it may have spread. But this newer type of therapy works differently, targeting and blocking the specific mechanisms that encourage cancer cells to grow. 

For example, one in five breast cancers is HER2-positive, meaning that the cancer cells carry a protein on their surface called HER2, which makes cancer grow and spread more aggressively. One of the first effective targeted therapies developed for breast cancer, Herceptin (trastuzumab), targets this protein and binds with it, blocking its action. Other targeted therapies block other ways that cancers grow, such as preventing them from forming new blood vessels.