Understanding Stage 1 Breast Cancer

Breast cancer, like other cancers, is staged. This is a determination of how much cancer has spread. The stages help guide treatment and prognosis.

Stage 1 breast cancer is confined to where abnormal cell division began. It has not spread yet to anywhere else in the breast or body. Therefore, it is further subdivided into Stages 1A and 1B. When detected at this early stage, treatment is usually very effective and the prognosis is good.

This article discusses what stage 1 breast cancer is, what treatment options you have, as well as your chances of surviving this type of cancer.

Overview of Stage 1 Breast Cancer

Stage 1 breast cancer is the earliest stage of what's considered invasive breast cancer. "Invasive" does not mean cancer has invaded other areas of your body. Instead, it means that the cells in your tumor have infiltrated the area past what's called the basement membrane.

When a tumor begins, it has not yet grown past this membrane and isn't considered cancer but carcinoma in situ. These tumors are referred to as stage 0 tumors. Carcinoma in situ is 100% curable with surgery since the cells are completely contained.

Stage 1 tumors are the earliest stage of invasive breast cancer. These tumors are small, and if they have spread to lymph nodes, the spread is only microscopic.

Staging of Breast Cancer

To understand how your healthcare provider determines the stage of your cancer and if you have a stage 1A or stage 1B tumor, it's helpful to know a little about the TNM system of classification.

• T = Tumor Size: All stage 1 cancer is T-0 or T-1, meaning your tumor is 2 centimeters (cm, roughly 1 inch) or less in diameter.
• N = Nodes: All stage 1 cancer is N-0 or N-1mi. N-0 means it has not spread to any lymph nodes. N-1 means that it has spread to lymph nodes nearby. The "mi" means there are micrometastases, which can only be seen under the microscope. Micrometastases measure between 0.2 millimeters (mm) and 2 mm (0.2 cm) in diameter.
• M = Metastases: M-0 means cancer has not metastasized (spread to other areas of the body).

Thus, using the TNM system, stage 1 cancers are defined as follows:

It can be confusing and a little alarming if you read your pathology report, and it says cancer has "metastasized to lymph nodes." This does not mean you have metastatic breast cancer (stage 4 breast cancer). You can have lymph node metastases even with early-stage disease.

Overall, stage 1 tumors are smaller than 1 inch in diameter, and either do not have lymph node involvement or have spread to nearby lymph nodes only on a microscopic level. Once you know the stage of your breast cancer, several more things will be considered in selecting the best treatment options for you.

Tumor Grade

Tumor grade is a number that describes the aggressiveness of a tumor. Pathologists look at the cancer cells from a biopsy and/or surgery under a microscope to determine things such as how actively cells are dividing. Tumors are then given a grade of 1, 2, or 3, with 1 being the least aggressive and 3 being the most aggressive.

Your tumor grade doesn't necessarily tell you what your prognosis will be, but it does help you and your healthcare provider choose the most appropriate treatments.

Receptor Status

You'll also need to know your tumor's receptor status. Receptors are proteins found on the surface of cancer cells that can tell what fuels the cell's growth and division. The three types include:

• Estrogen receptors
• Progesterone receptors
• HER2

Once your tumor cells are tested, you'll be told whether it's:

• Estrogen receptor (ER) positive or negative
• Progesterone receptor (PR) positive or negative
• HER2 positive or negative
• Triple-negative, if all the above receptors are not found

Treatment of Stage 1 Breast Cancer

Treatment options for stage 1 breast cancer fall into two main categories:

• Local treatments: These treat cancer at the site and include surgery and radiation therapy.
• Systemic treatments: These treat cancer throughout the body and include chemotherapy, hormonal therapy, targeted therapy, and immunotherapy.

If a tumor is very small, local treatments are usually all that's required. If the tumor is larger, more aggressive (has a higher tumor grade), has spread to lymph nodes, or has a molecular profile that indicates it's more likely to spread, systemic treatments are usually recommended.

With stage 1 breast cancers, the use of systemic therapy is considered adjuvant (add-on) therapy. The goal is to eliminate any cancer cells that may have spread beyond the breast but are too small to be detected.

Work with your healthcare provider to weigh the pros and cons of each option for your situation.

Breast Cancer Healthcare Provider Discussion Guide

Get our printable guide for your next healthcare provider's appointment to help you ask the right questions.

Download PDF

Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life.

Email Address

Sign Up

You're in!

Thank you, {{form.email}}, for signing up.

There was an error. Please try again.

Surgery

Surgery is recommended for the majority of stage 1 cancers. Options include either a lumpectomy (removal of only part of the breast) or a mastectomy (removal of the entire breast). People choose one over the other for several reasons, and it can be a very personal choice.

If you choose a lumpectomy, following up with radiation therapy is usually recommended.

If you opt for a mastectomy, your healthcare provider will talk to you about the option of breast reconstruction. Skin-sparing surgery is becoming more common. In this procedure, an implant or an expander is often placed at the same time as your mastectomy. In addition, depending on your risk factors, you may need to weigh the risks and benefits of having a single vs. double mastectomy.

In addition to discussing the efficacy of these options with your healthcare provider, be sure to also talk about what you can expect cosmetically with each procedure.

Radiation Therapy

If you have a lumpectomy, radiation therapy is usually used to treat your remaining breast tissue.

Radiation can be done after both lumpectomy and mastectomy. Even with a mastectomy, the surgeon cannot get every cancer cell. Radiation helps kill cancer cells that may have been left behind or those that are too small to be seen.

Chemotherapy

Chemotherapy is sometimes used as an adjuvant treatment for stage 1 breast cancer.

The purpose of chemotherapy is to treat any cancer cells that may have strayed from your breast before they can grow into metastases.

The use of chemotherapy is also very dependent on the receptor status of the tumor. In a person who is HER-2 positive or triple-negative, chemotherapy is often used even if the lymph nodes are completely negative.

However, it's traditionally been difficult to determine who will benefit from chemotherapy, and it's especially difficult with node-negative stage 1 breast tumors that are positive for hormone receptors and negative for HER-2.

The Oncotype Dx Recurrence Score or MammaPrint are genomic tests that can be helpful in determining who should undergo chemotherapy. Those who score higher on the test are at higher risk for recurrence, and chemotherapy can increase their survival rates. Those with low scores, meanwhile, are not likely to benefit from chemotherapy.

However, these tests are only used in people with estrogen and/or progesterone-positive tumors that are also HER-2 negative. They are not used in people with triple-negative or HER-2 positive breast cancer. 

Since some of the long-term potential side effects of chemotherapy can be severe—such as heart damage or failure and secondary leukemia—it's important to weigh the possible risks and benefits. Talk with your healthcare provider about the risks of each recommended chemotherapy drug and what it may mean for you.

Hormone Therapies

If your tumor is estrogen receptor-positive, hormonal therapy is usually recommended following primary treatment with surgery, chemotherapy, and radiation. The purpose is to reduce the risk of cancer coming back.

Estrogen receptor-positive tumors are more likely to have a late recurrence (more than five years after diagnosis). The drug tamoxifen is often used for premenopausal women. For postmenopausal women, treatment is usually an aromatase inhibitor such as Aromasin (exemestane), Arimidex (anastrozole), or Femara (letrozole). In some high-risk premenopausal women, an aromatase inhibitor is sometimes used with drugs to suppress ovarian function.

HER2 Targeted Therapies

If your tumor is HER2 positive, a HER2-targeted medication such as Herceptin (trastuzumab) is usually started after primary treatment.

It is important to choose the treatments that are best for you, no matter what someone else may choose. It's also very important to be your own advocate for your cancer care. People living with cancer and healthcare providers are working together much more closely than in the past, and you are a vital member of your cancer team.

Is Stage 1 Breast Cancer Curable?

For those with localized, early-stage breast cancer who receive treatment with surgery and chemotherapy or radiation therapy, if recommended, the five-year survival rate is close to 100%.

Even so, going through treatment for stage 1 breast cancer can be challenging. Side effects are common, especially with chemotherapy, and fatigue is almost universal.

Follow-Up Care for Stage 1 Breast Cancer

After your initial breast cancer treatment is over, expect follow-up care to last another five years or possibly more. Ongoing treatments depend on multiple factors and may include:

• Regular appointments with your oncologist
• Hormone therapy
• Bisphosphonate therapy

You need to know the signs and symptoms of a recurrence so you can alert your healthcare provider immediately if you suspect cancer has come back.

Coping with Stage 1 Breast Cancer

When you have stage 1 breast cancer, your emotions may span the spectrum from fear and worry to confusion and panic. It's important to have an outlet for your feelings and to remember that it's OK (and understandable) to have a bad day.

You may encounter some people who say things like, "It's only stage 1," which can feel diminishing. While some may say this because they are unaware of the diagnosis's significance and the treatment involved, others may say this in an attempt to make you feel better (i.e., "at least it's not stage 4"). You are entitled to your feelings about your diagnosis, no matter what others say, but it may help to know these comments are likely well-intentioned.

One of the best things you can do for yourself is to gather a support network. Consider the people in your life you can lean on, both emotionally and practically. Even if you are feeling good through your treatment, it can be exhausting. Ask for help and allow people to give it to you.

Getting involved in a support group or online support community can be priceless. There is something special about talking to others who are facing the same challenges you are. These communities also offer a chance to learn about the latest research on breast cancer, as nobody is as motivated as those living with the disease.

Summary

Stage 1 breast cancer is very treatable with surgery, radiation, chemotherapy, or targeted therapies. It is considered early-stage breast cancer and the prognosis is good. Talk with your treatment team about what your diagnosis means and what treatment options may be best for you. Ask any questions you have—your treatment team is there for that reason!