Treatment of Stage 3 Breast Cancer

Medically Reviewed by Brian S. Englander, MD
Written by Vanessa LeongFeb 1, 202412 min read
Treatment of Stage 3 Breast Cancer

Source: Shutterstock

What is stage 3 breast cancer?

Breast cancer is a complex disease that can progress through different stages, each presenting a unique set of challenges. Stage 3 breast cancer in particular, is an advanced stage of breast cancer presenting more challenging circumstances.

Anatomically, stage 3 breast cancer is where the cancer has spread beyond the breast and nearby lymph nodes to other tissues within the breast or to the chest wall. Stage 3 is further divided into subcategories, including Stage 3A, Stage 3B, and Stage 3C, based on the extent and locations of the cancer:

  • Stage 3A Breast Cancer
    • There is cancer in 4 to 9 underarm (axillary) lymph nodes or lymph nodes near the breastbone (internal mammary nodes). There may or may not be any visible cancer in the breast and the cancer may be of any size.
    • Or, cancer in the breast is larger than 5cm and has spread to 1 to 3 axillary lymph nodes or internal mammary nodes.
  • Stage 3B Breast Cancer
    • The cancer has spread to the chest wall or the skin of the breast.
    • The cancer may have also spread to up to 9 axillary or internal mammary nodes.
  • Stage 3C Breast Cancer
    • This stage represents extensive lymph node involvement, with cancer found in 10 or more axillary lymph nodes or internal mammary nodes.
    • Or, cancer cells are found in lymph nodes above or below the collarbone (supraclavicular or infraclavicular nodes).
    • There may or may not be any visible cancer in the breast and the cancer may be of any size.

Stage 3 breast cancers can also include inflammatory breast cancers. The methods of treatment for these cancers are slightly different.

It is important to note that many medical institutions, especially in the United States, now use an updated staging system which includes other factors to determine a patient’s treatment and outcome. This is known as prognostic staging. Prognostic staging takes into account the tumor grading, estrogen receptor (ER) status, progesterone receptor (PR) status and HER2 status, in addition to the cancer’s anatomical characteristics. In this current staging system, the stage of cancer is determined from a combination of all of these factors. While it is a more accurate classification, it is also much more complex. Therefore, it is best to consult your doctor on your specific cancer classification and what it means.

Learn more: Breast Cancer Staging and Survival Rates

What treatment is necessary for stage 3 breast cancer?

The treatment for Stage 3 breast cancer is more aggressive than that of earlier stages. Treatment often starts with neoadjuvant (pre-operative) systemic treatment such as neoadjuvant chemotherapy, hormone therapy and targeted drug therapy, with the purpose of shrinking the tumors as much as possible. Treatment will also include local therapies such as surgery and radiation therapy.

Systemic therapy

Systemic therapy is a type of cancer treatment that is designed to target cancer cells throughout the entire body. Unlike local therapies, which focus on treating the tumor and surrounding area, systemic therapies are delivered through the bloodstream and can reach cancer cells in various parts of the body. In stage 3 breast cancer, systemic therapies may be used as a neoadjuvant treatment to shrink tumors to reduce the extent of surgery, or they may be used as an adjuvant treatment to kill remaining cancer cells and reduce the recurrence risk.

The types of systemic therapy used for stage 3 breast cancer include:

If the breast cancer is hormone receptor-positive (estrogen or progesterone receptor-positive), adjuvant hormone therapy (such as tamoxifen or an aromatase inhibitor) may be recommended to block the effects of hormones on cancer cells.

In cases where the cancer overexpressed HER2/neu receptors (HER2-positive), targeted therapies like Herceptin (trastuzumab) are often used both as a neoadjuvant therapy as well as an adjuvant therapy.

In some cases, CDK4/6 inhibitors may be used for hormone receptor-positive cancers.

Chemotherapy can be given as a neoadjuvant therapy or an adjuvant therapy. People with triple-negative breast cancer or HER2-positive breast cancer often benefit from neoadjuvant chemotherapy as the first treatment. The cancer may completely go away. If not, surgery is needed and depending on how much cancer is left, other treatments may be considered post-surgery.

To help determine how much chemotherapy will benefit you, especially if you have HER2-negative breast cancer or hormone receptor-positive breast cancer, a genomic assay such as Oncotype DX and MammaPrint may be used to analyze the tumor's genetic characteristics.

In some cases, such as triple-negative breast cancer, immunotherapy may also be used.

Local therapy

Local therapy refers to treatments that target the cancerous tumor and the surrounding area without affecting the entire body. It is often used with the goal of removing or destroying the cancer cells in a specific area while preserving as much healthy tissue as possible.

The types of local therapy used for stage 3 breast cancer include:

In this procedure, the surgeon removes the tumor and a small margin of healthy tissue around it. This allows the patient to keep most of their breast. After a lumpectomy, radiation therapy is often recommended to reduce the risk of cancer recurrence in the breast.

For stage 3 breast cancer, where the tumor is often large or has spread to many lymph nodes, lumpectomy is often not possible. However, if neoadjuvant therapies are able to shrink the tumor enough, then lumpectomy can still remain a treatment option. For some women with large breasts relative to the tumor size, lumpectomy may be an option, provided the cancer has not spread into nearby tissues.

In a mastectomy, the entire breast is removed. A mastectomy is a common surgical treatment done on patients with stage 3 breast cancer due to the tumor size. In some cases, a nipple-sparing mastectomy or skin-sparing mastectomy may be possible to preserve breast appearance.

Radiation therapy will often be given after a mastectomy for stage 3 breast cancer.

ALND is an operation to remove most or all of the lymph nodes under the arm. Due to the extent of spread to lymph nodes in many stage 3 breast cancer cases, ALND is a common surgical procedure to remove the affected lymph nodes.

As stage 3 breast cancer patients often require adjuvant therapies, it is typically recommended that any breast reconstruction surgery be delayed until after the completion of post-operative therapies such as chemotherapy and radiation therapy.

Radiation therapy is a cancer treatment method that uses high doses of radiation to kill cancer cells and shrink tumors. Radiation therapy is often recommended post-surgery for stage 3 breast cancer patients.

If adjuvant chemotherapy is needed, radiation therapy may be delayed until after the completion of chemotherapy.

Treatment decisions are highly individualized and depend on various factors, including the specific characteristics of the cancer, the patient's overall health, and their preferences. The goal of treatment is to control the cancer, prevent its spread, and improve the chances of long-term survival. Regular follow-up and monitoring are essential to detect any signs of recurrence or complications. Treatment for stage 3 breast cancer can be challenging, but with the advancements in cancer care, there are several options available that have significantly improved the outcomes for many patients.

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This article has been medically reviewed and fact-checked to ensure our content is informed by the latest research in cancer, global and nationwide guidelines and clinical practice.

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