What You Need to Know About Stage 1 Breast Cancer

Definition, Diagnosis, Treatments, and Prognosis

woman with breast cancer and pink bra with doctor checking x-ray looking for metastases
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A diagnosis of any stage of breast cancer can cause fear and panic. Even though you may be reassured that you have the earliest stage of breast cancer you may feel frightened and overwhelmed. We've learned that our emotional reactions to the diagnosis are similar no matter what the prognosis. What is the definition of a stage 1 tumor, what treatment options are available, and what is your prognosis?

While we can't promise that educating yourself will ease all of your fears, it can help you slide into the driver's seat and feel more empowered in your care.

Definition

Stage 1 breast cancer is the earliest stage of "invasive" breast cancer. Seeing the word invasive is frightening, but the term invasive with regard to stage does not mean that the cancer is invaded other areas of the body. Invasive simply means that the cells in your tumor have invaded past something called the basement membrane. It is this invasion past the basement membrane which defines something as cancer.

When breast cancer first begins, it has not yet grown past this membrane. Tumors at this stage are not considered cancer, but rather carcinoma-in-situ. They are also referred to as stage 0 tumors. Carcinoma-in-situ is 100 percent curable with surgery since the cells are contained completely. There is no chance it could spread.

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

Stage and TNM Classification

To understand how your doctor 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.

In this setting:

  • T stands for tumor size: A score of T1 means that your tumor is 2 cm (roughly an inch) or less in diameter. In general, T2 tumors are larger than 2 cm and smaller than 5 cm, with T3 tumors being larger than 5 cm.
  • N stands for nodes: N0 means that the cancer has not spread to any lymph nodes. N1 means that the cancer has spread to lymph nodes nearby, and N2 means that it has spread to lymph nodes slightly farther away. With stage 1 tumors, another term becomes important. The term micrometastases means that the cancer has spread to lymph nodes but can only be seen under the microscope. Micrometastases are present when cancer cells are found in the lymph node and are greater than 0.2 mm in diameter but less than 2 mm (0.2 cm) in diameter. A cancer that has micrometastases in a nearby lymph node would be described as T1mi. Macrometastases, in contrast, refer to cancer in the lymph nodes that is larger than 2 mm in diameter (and can, in theory, be seen with the naked eye).
  • M stands for metastases: M0 means that the cancer has not metastasized (for example, to bones, the brain, or liver). M1 means it has.spread.

It can be confusing (and very frightening) if you read your pathology report and note that it says that the cancer has "metastasized to lymph nodes." This does not mean that you have metastatic breast cancer (stage 4 breast cancer).

You can have lymph node metastases even with early-stage disease.

Using the TNM system, stage 1 cancers are divided further into:

  • Stage 1A: T1N0M0. The tumor is less than 20 mm (2 cm) in size and there is no spread to lymph nodes
  • Stage 1B: T1N1miM0 or T0N1miM0. With the first combination, the tumor is less than 20 mm (2 cm) in size and there are micrometastases in a nearby lymph node. The other scenario is much less common and is present if there is no evidence of a primary tumor in the breast but there are micrometastases in a lymph node (usually in the armpit).

Overall, stage 1 tumors are those which are smaller than an inch (2 cm) in diameter and either do not have lymph node involvement or have spread to nearby lymph nodes but only on a microscopic level.

Once you know the stage of your breast cancer there are several more things you will need to know before selecting the best treatment options.

Types

There are several different types of breast cancer. Invasive ductal carcinomas are most common followed by invasive lobular carcinomas. Other, less common types of breast cancer include inflammatory breast cancer, medullary carcinoma, tubular carcinoma, and more.

Tumor Grade

Tumor grade is a number which 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 tumors. Your tumor grade doesn't necessarily tell you what your prognosis will be, but rather helps you and your physician choose the best treatments.

MultigeneTesting

In the last decade or so we've learned how every tumor is different at a molecular level. In other words, two tumors that are stage 1 ductal carcinomas and have a tumor grade of 2 can behave differently. If you do not have any positive lymph nodes and a small tumor, your oncologist may recommend looking at this testing in order to see if adjuvant treatments like chemotherapy are necessary. Multigene tests such as Oncotype DX and MammaPrint can be used to determine if chemotherapy is needed for node-negative breast cancer.

Receptor Status

In choosing the best treatments for your breast cancer, your physician will want to test the receptor status of your cancer. Receptors are proteins found on the surface of cancer cells and are important in the growth of the cells.

Estrogen Receptors

Estrogen receptors are proteins (receptors) found on the surface of the cancer cells. Breast cancers which are estrogen-receptor positive are stimulated to grow when estrogen combines with these receptors.

Progesterone Receptors

Progesterone receptors often go hand in hand with estrogen receptors.

HER2 Positive Cancers

Some breast cancers are referred to as HER2 positive. HER2 is a protein on the surface of cancer cells. Growth factors bind with this receptor to stimulate growth. All normal breast cells have HER2 receptors, but with HER2 positive cancers, there are roughly 100 times as many of these receptors (you may see terms such as HER2 amplification referring to extra genes coding for the protein or HER2 overexpression, referring to the increased numbers of the receptors on cancer cells).

There are specific treatments that can target these receptors that may reduce the risk of recurrence. If all of your receptors are "negative" on testing, your tumor would be considered "triple negative" breast cancer.

Treatments

Treatments are first broken down into two main categories:

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

If a tumor is very small, local treatments are usually all that are 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 the cancer would be more likely to spread, systemic treatments are usually recommended. With stage 1 breast cancers the use of systemic therapy is considered adjuvant therapy (add-on therapy) and the goal is to eliminate any cancer cells which have spread beyond the breast but are too small to be detected by imaging tests we currently have.

Specific treatment options may include:

Surgery

Surgery is recommended for the majority of stage 1 cancers. Options include either a lumpectomy or a mastectomy. There are a number of reasons people choose one over the other, and it can be a very personal choice. If a lumpectomy is chosen, radiation therapy to the remaining breast tissue is usually recommended. If you have a mastectomy, your doctor will talk to you about the option of breast reconstruction. Skin-sparing surgery is becoming more common, and with this procedure, an implant or at least an expander are often placed at the same time as your mastectomy.

With surgery, a sentinel node biopsy may be done. In the past, several lymph nodes were usually removed and then examined under the microscope, but we can now determine which lymph nodes a cancer will first spread to, and sample only those nodes. If your lymph nodes are positive it means that the cancer has essentially declared its intent to spread.

Chemotherapy

Chemotherapy for breast cancer is sometimes used as adjuvant treatment with stage 1 disease, though it has traditionally been difficult to determine who will benefit. For those who have micrometastases to lymph nodes, chemotherapy is often recommended. The purpose of chemotherapy is to treat any cancer cells which may have strayed from your breast before they can grow into metastases. Cancers which have spread (even in a small amount) to lymph nodes have essentially declared their intent to spread further.

With node-negative breast cancers which are 2 cm in diameter or less (stage 1) it is less clear. The Oncotype Dx Recurrence Score or MammaPrint are multigene genomic test that can be helpful. Those who score higher on the test have increased survival rates when chemotherapy is given. Those with low scores are not likely to benefit from chemotherapy. Since chemotherapy has potential side effects (such heart failure and secondary leukemia though uncommon) it's important to weigh the possible risks and benefits with each person individually.

Radiation Therapy

If you have a lumpectomy, radiation therapy is usually used to treat your remaining breast tissue. With stage 1 breast cancer, radiation therapy is not usually needed after a mastectomy.

Hormone Therapies

If your tumor is estrogen receptor positive, hormonal therapy is usually recommended following primary treatment with surgery and chemotherapy/radiation therapy. The purpose is to reduce the risk that the cancer will come back. Estrogen receptor positive tumors are more likely to have a late recurrence (after 5 years and beyond). For premenopausal women, tamoxifen is often used. For postmenopausal women, treatment is usually an aromatase inhibitor such as Aromasin (exemestane), Arimidex (anastrozole), or Femara (letrozole).

HER2 Targeted Therapies

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

Clinical Trials

The only way progress is made in the treatment of breast cancer is through studying new drugs and procedures in clinical trials. There are many myths about clinical trials, but the truth is that every treatment we now use was once studied in a clinical trial.

Choosing the Best Treatment

With stage 1 breast cancer one of the biggest decisions is what type of surgery to have. There are pros and cons to each surgery, and many factors should be considered such as your family history (the chance you will develop another breast cancer), where your tumor is located in your breast, and what you can expect cosmetically with each procedure. It is important to choose the treatments which are best for you, no matter what someone else may choose. It's also very important to be your own advocate in your cancer care. Patients and doctors are working together much more closely that in the past and you are a vital member of your cancer team.

Coping and Support

One of the best things you can do for yourself after your diagnosis is to gather a support network. You may wish to even write down a list of friends who can provide support. Even if you are feeling good through your treatment it can be exhausting to add these treatments to our all-ready-to-busy schedules. Ask for help and allow people to help.

You may wish to set up a CaringBridge site or have someone do this for you. This is an excellent way to keep all of your family and friends abreast of your situation without spending countless hours each day on the phone. Your friends will appreciate the opportunity to comment and write you notes without worrying about disrupting your rest. There are also sites which allow people to sign up to bring meals, drive you to radiation visits, and other help such as Take Them a Meal and Lotsa Helping Hands.

Emotionally you may feel like you are crumbling at times. Studies tell us that people react in a similar way after a diagnosis of cancer and it doesn't matter if it is early stage or advanced. Don't let anyone make you feel funny by saying "it's only stage 1." It's cancer, and cancer is scary! Your emotions may span the spectrum from fear to worry to confusion to panic—sometimes in a manner of minutes. You don't always have to be positive and it's important to express your negative emotions as well.

Getting involved in a support group or online support community can be priceless. There is something very 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 there is nobody as motivated as those living with the disease.

Prognosis

The prognosis for stage 1 breast cancer is good. For those who receive treatment with surgery and chemotherapy or radiation therapy, if recommended, the 5-year survival rate is close to 100 percent. That said, going through treatment for stage 1 breast cancer is not easy. Side effects are common, especially with chemotherapy, and fatigue is almost universal.

A Word From Verywell

A diagnosis of stage 1 breast cancer is frightening. Even though the survival rates are very good, it can be challenging to think about all the steps you need to take to get there. Lean on others and allow them to help you. Many cancer centers have support groups or mentors for those newly diagnosed. Taking the time to visit with people who have gone through the treatments and come out not just surviving, but thriving, can be an encouragement on those days when cancer fatigue hits.

Sources

McVeigh, T., and M. Kerin. Clinical Use of the Oncotype DX Genomic Test to Guide Treatment Decisions for Patients With Invasive Breast Cancer. Breast Cancer (Dove Med Press). 2017. 9:393-400.

National Cancer Institute. Breast Cancer Treatment (PDQ)—Health Professional Version

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