Early/Moderate Stage Breast Cancer: Staging and Treatment

Author: Marisa Healy, BSN, RN
Content Contributor: Christopher Dolinsky, MD, Christine Hill-Kayser, MD, Katherine Okonak, MSW, LSW
Last Reviewed: March 18, 2024

What is staging for cancer?

Staging is a way to find out how much cancer is in your body, how far it has spread, and what treatment can be used. Staging looks at the size of the tumor and where it is, and if it has spread to other organs. Tests like biopsies, CTs, and MRIs are done to help stage your cancer. Your providers need to know about your cancer and your health so that they can plan the best treatment for you.

The staging system for breast cancer is called the “TNM system,” as described by the American Joint Committee on Cancer. It has three parts:

  • T-describes the size/location/extent of the "primary" tumor in the breast.
  • N-describes if the cancer has spread to the lymph nodes.
  • M-describes if the cancer has spread to other organs (metastasized).

Your healthcare provider will use the results of the tests you have to figure out your TNM result and use these to get a stage from 0 to IV (4). 

How is breast cancer staged?

This article will focus on early/moderate stage breast cancer in women. Learn more about male breast cancer here.

Breast cancer is staged into five groups. Staging is based on:

  • The size of your tumor on the mammogram.
  •  What is found after surgery.
  • Any sign of spread to other organs (metastasis).
  • Surgery to test if your lymph nodes have cancer cells.

Staging is important because it helps guide your treatment options. Stages 0, I (1), and II (2) are early or moderate stages.

The staging system is very complex. Below is a summary of the staging system. Talk to your provider about the stage of your cancer.

  • Stage 0 (called carcinoma in situ/non-invasive breast cancer):
    • Lobular carcinoma in situ (LCIS): abnormal cells line a gland in the breast. This is a risk factor for future cancer, but this is not thought to be cancer itself.
    • Ductal carcinoma in situ (DCIS): abnormal cells line a duct in the breast. Women with DCIS have a higher risk of getting invasive breast cancer in that breast. Treatment options are similar to patients with Stage I breast cancers.
  • Stage I: early-stage breast cancer where the tumor is less than 2 cm and hasn't spread to lymph nodes or other parts of the body.
  • Stage II: early-stage breast cancer where the tumor is either less than 2 cm and has spread to 1-3 lymph nodes under the arm; or the tumor is between 2 and 5 cm (with or without spread to the lymph nodes under the arm), or the tumor is greater than 5 cm and hasn't spread outside the breast.
  • Stage III: this is called locally advanced breast cancer. The tumor is greater than 5 cm and has spread to the lymph nodes under the arm; or the cancer is found in more than 3 underarm lymph nodes; or cancer has spread to lymph nodes near the breastbone or to other tissues near the breast.
  • Stage IV: metastatic breast cancer in which cancer has spread outside the breast to other organs in the body.

Based on the stage of your cancer, your provider may want more tests to see if the cancer has spread to any other organs outside of the breast and nearby lymph nodes. Your providers will talk with you about what is needed to stage your cancer.

This article will focus on treatment for “early” or “moderate” stage breast cancer (Stage 0, I, and II).

How is early/moderate stage breast cancer treated?

Treatment for breast cancer depends on many things, like your cancer stage, age, overall health, and testing results. If you have early or moderate stage breast cancer, your treatment may be different than someone who has advanced breast cancer. Your treatment may include some or all of the following:


Almost all women with early or moderate-stage breast cancer will have some type of surgery during treatment. Surgery is used to test lymph nodes for cancer and to remove as much of the cancer as possible. There are many ways that surgery can be done:

  • Lymph Node Removal and Testing: If you have invasive breast cancer (any stage except stage 0), you should have lymph nodes removed and tested. This may be done with:
  • Breast-Conserving Surgery (BCS): You may have the option to have breast-conserving surgery (BCS). If you have BCS, you may also need radiation therapy after surgery to help prevent the cancer from coming back in that breast (recurrence). BCS may be:
    • Lumpectomy: the tumor and some normal tissue is removed.
    • Segmental/partial mastectomy: a larger piece of tissue, but not the whole breast, is removed.
  • Modified radical mastectomy: The whole breast is removed, along with some lymph nodes for testing. Many women who have modified radical mastectomies choose to also have breast reconstruction. If you would like reconstruction, you should try to meet with a plastic surgeon before your mastectomy to talk about reconstruction options. The reconstruction process can be started at the same time as the mastectomy or done later. Learn more about breast reconstruction.

The breast tissue that is removed during BCS and any lymph nodes that are removed will be looked at by a pathologist under a microscope. A report will be written that has:

  • The type of cancer cells that are seen.
  • The size of the cancer.
  • The number of lymph nodes that have cancer in them.
  • Information about the cancer such as “grade” (how aggressive the cells look), if it has receptors for estrogen, progesterone (ER, PR), and HER2.

These findings will help decide what treatment will work best for you.


Chemotherapy is the use of anti-cancer medicines that go through your whole body. Even when tumors are taken out by surgery, tiny cancer cells can be left behind. These cancer cells can spread to other parts of the body (metastasize). Chemotherapy helps get rid of these cancer cells and can help prevent the cancer from coming back (recurring). 

Chemotherapy can help if you have early or moderate-stage disease. Your age and overall health, as well as the biological makeup of your breast tumor, help your team decide if you should have chemotherapy. In most cases, the genetic makeup of your tumor (tested with OncoType Dx and MammaPrint) will be used to see if chemotherapy could be helpful. 

There are many different chemotherapy medicines. They are often given in combinations (called a regimen) for 3 to 6 months after surgery for early/moderate stage breast cancer. Most chemotherapies used for breast cancer are given through a vein (intravenously/IV). 

Medications that are commonly used in early/moderate stage breast cancer treatment include adriamycin (doxorubicin), cyclophosphamide, taxanes (taxol and taxotere), methotrexate, and 5-FU. Your oncology team will go over the best regimen for your cancer. You can work with your providers to choose the best plan for you.


You may need radiation therapy. Radiation therapy uses high-energy x-rays to kill cancer cells. Radiation therapy is recommended for nearly all early-stage breast cancer patients who have breast-conserving surgery. Radiation helps lower the risk of the cancer coming back in the same breast (local recurrence). Your radiation oncologist can answer questions about the benefits, process, and side effects of radiation therapy. In general:

  • You will need to go to a radiation therapy treatment center 5 days a week for up to 6 weeks for treatment.
  • For early/moderate stage breast cancer, you will get treatment to the whole breast for 4-5 weeks; the final 1-2 weeks of treatment often involve a "boost" of radiation that is only given to the area in the breast where the tumor was.
  • The treatment is painless and takes just a few minutes.

Some other ways to deliver radiation for early/moderate-stage breast cancers are:

  • More radiation is given per day to the whole breast so that the treatment takes only 4 weeks (called hypofractionation).
  • Brachytherapy or Mammosite. This reduces the treatment time to 1 week but is not an option for many patients.

These techniques are only helpful for some patients. Your radiation oncologist will talk with you about the best course of treatment for your cancer.

Hormone Therapy

If your tumor has estrogen (ER) and/or progesterone (PR) receptors, it may be treated with hormone therapy. Hormone therapies include tamoxifen and medications called aromatase inhibitors (anastrozole,letrozole, exemestane). These medications are taken in pill form for 5-10 years after breast cancer surgery. They have been shown to lower your risk of recurrence (the cancer coming back) if your tumor has estrogen receptors.

These medications can have side effects. When taking tamoxifen you may have:

  • Weight gain.
  • Hot flashes.
  • Vaginal dryness and discharge.

Taking tamoxifen may raise your risk of serious medical issues, such as blood clots, stroke, and uterine cancer.

When taking aromatase inhibitors (AIs), you may have:

Patients taking AIs should have bone density testing before starting treatment and as needed.

Targeted Therapy

Targeted therapies are medications that target something specific to the cancer cells, stopping them from growing and dividing.

HER-2 is a receptor that is found in about 25% of breast cancers. These are called HER2-positive breast cancers. These tumors may grow faster and are more likely to spread. There are medications that target the HER2 protein. The most common is trastuzumab (Herceptin®), which may be given to treat the cancer or stop it from coming back (recurring). Pertuzumab (Perjeta), neratinib (Nerlynx), and ado-trastuzumab emtansine (Kadcyla) also treat some early-stage HER2 positive cancers.

Other targeted therapies are:

Talk with your healthcare provider about if targeted therapies may work on your tumor.


Immunotherapy uses your body’s own immune system to find and kill cancer cells. It can be given into a vein, taken by mouth, injected under the skin (subcutaneous), or put into a body cavity to treat a specific site. Some of the Immunotherapies used for breast cancer are:

Talk with your healthcare provider about immunotherapy and if it may be a part of your treatment plan.

Clinical Trials

You may be offered a clinical trial as part of your treatment plan. To find out more about current clinical trials, visit the OncoLink Clinical Trials Matching Service.

Making Treatment Decisions

Your care team will make sure you are part of choosing your treatment plan. This can be overwhelming as you may be given a few options to choose from. It feels like an emergency, but you can take a few weeks to meet with different providers and think about your options and what is best for you. This is a personal decision. Friends and family can help you talk through the options and the pros and cons of each, but they cannot make the decision for you. You need to be comfortable with your decision – this will help you move on to the next steps. If you ever have any questions or concerns, be sure to call your team.

You can learn more about breast cancer at OncoLink.org.

Abeloff, M., Armitage, J., Niederhuber, J., Kastan, M. & McKenna, G. (Eds.): Clinical Oncology (2008). Elsevier, Philadelphia, PA.

American Cancer Society. About breast cancer. 2022.

American Cancer Society. Immunotherapy for Breast Cancer. 2021.

Breast cancer screening guidelines. 2017. 

Anders CK, Zagar T & Carey LA. (2013).The management of early-stage and metastatic triple-negative breast cancer: a review. Hematology/Oncology Clinics of North America. 27(4):737-749.

Goldhirsch A, Winer EP, Coates AS, Gelber RD, Piccart-Gebhart M, Thurlimann B & Senn H.(2013). Personalizing the treatment of women with early breast cancer: highlights of the St Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer. Annals of Oncology. 24(9):2206-2223.

Janni, W. (2016). Targeted Therapy of Breast Cancer. Oncology Research and Treatment, 39(3), 100-101

Kono, M., Fujii, T., Lim, B., Karuturi, M. S., Tripathy, D., & Ueno, N. T. (2017). Androgen Receptor Function and Androgen Receptor–Targeted Therapies in Breast Cancer: A Review. JAMA Oncology.

Manguso N, Gangi A & Giuliano AE. (2015). Neoadjuvant Chemotherapy and surgical management of the axilla in breast cancer: a review of current data. Oncology. 29(10):733-738.

National Comprehensive Cancer Network. Clinical practice guidelines: breast cancer. 2017. (login required).

Pistelli, M., Della Mora, A., Ballatore, Z., & Berardi, R. (2018). Aromatase inhibitors in premenopausal women with breast cancer: the state of the art and future prospects. Current Oncology, 25(2), e168.

Ponde, N. F., Zardavas, D., & Piccart, M. (2019). Progress in adjuvant systemic therapy for breast cancer. Nature reviews Clinical oncology, 16(1), 27-44.

von Minckwitz, G., Procter, M., de Azambuja, E., Zardavas, D., Benyunes, M., Viale, G., ... & Knott, A. (2017). Adjuvant Pertuzumab and Trastuzumab in Early HER2-Positive Breast Cancer. New England Journal of Medicine.

Whelan TJ et al. Regional Nodal Irradiation in Early-Stage Breast Cancer. The New England Journal of Medicine. 373:307-316. 2015.

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