What Are Breast Cancer Survival Rates by Stage?

What is breast cancer staging?

Breast Cancer Stages
Breast cancer stages are classified according to cancer tumor size, location, and extent of spread.

Breast cancer staging is the determination of the extent and spread of the cancer. An individual's health care team uses stages to summarize the extent of the cancer in a standardized way that is recognized by all health care providers. They use this staging to determine the treatment most appropriate for the type of cancer. Cancer staging helps to determine the prognosis, or outlook, of a cancer, including rates of recurrence and survival rates.

What are the stages of breast cancer?

Staging system

The most widely used system in the U.S. is the American Joint Committee on Cancer (AJCC) TNM system. Medical professionals developed a new eighth edition of this staging system for 2018 that includes results of testing for certain biomarkers, including the HER2 protein, estrogen receptor (ER) and progesterone (PR), and the results of gene expression assays, in addition to the factors (TNM) described below.

Besides the information gained from the imaging tests, this system also uses the results from surgical procedures. After surgery, a pathologist looks at the cells from the breast cancer as well as from the lymph nodes. They incorporate this information into the staging, as it tends to be more accurate than the physical exam and X-ray findings alone.

The TNM system uses letters and numbers to describe certain tumor characteristics in a uniform manner. This allows health care providers to stage the cancer (which helps determine the most appropriate therapy) and aids communication among health care providers. The following is an abbreviated example of the TNM staging system.

T: This describes the size of the tumor. A number from 0 to 4 follows. Higher numbers indicate a larger tumor or greater spread:

  • TX: Primary tumor cannot be assessed
  • T0: No evidence of primary tumor
  • Tis: Carcinoma in situ
  • T1: Tumor is 2 cm or less across
  • T2: Tumor is 2 cm-5 cm
  • T3: Tumor is more than 5 cm
  • T4: Tumor of any size growing into the chest wall or skin

N: This describes the spread to lymph node near the breast. A number from 0 to 3 follows.

  • NX: Nearby lymph nodes cannot be assessed (for example, if they have previously been removed)
  • N0: There has been no spread to nearby lymph nodes. In addition to the numbers, this part of the staging is modified by the designation "i+" if the cancer cells are only seen by immunohistochemistry (a special stain) and "mol+" if the cancer could only be found using PCR (special detection technique to detect cancer at the molecular level).
  • N1: Cancer spreads to one to three axillary lymph nodes (underarm lymph nodes) or medical professionals find tiny amounts of cancer in internal mammary lymph nodes (lymph nodes near breastbone).
  • N2: Cancer has spread to four to nine axillary lymph nodes or the cancer has enlarged the internal mammary lymph nodes.
  • N3: Any of the conditions below:
    • Cancer has spread to 10 or more axillary lymph nodes with at least one cancer spread larger than 2 mm.
    • Cancer has spread to lymph nodes under the clavicle with at least area of cancer spread greater than 2 mm.

M: This letter is followed by a 0 or 1, indicating whether the cancer has spread to other organs.

  • MX: Medical professionals cannot assess metastasis.
  • M0: Health care providers find no distant spread on imaging procedures or by physical exam.
  • M1: Spread to other organs is present.

Once physicians determine the T, N, and M categories, they combine them into staging groups. There are five major staging groups, stage 0 to stage IV, which are subdivided into A and B, or A and B and C, depending on the underlying cancer and the T, N, and M scale.

Cancers with similar stages often require similar treatments.

What are breast cancer survival rates by stage?

Survival rates are a way for health care professionals to discuss the prognosis and outlook of a cancer diagnosis with their patients. The number most frequently discussed is 5-year survival. It is the percentage of patients who live at least 5 years after a cancer diagnosis. Many of these patients live much longer, and some patients die earlier from causes other than breast cancer. With a constant change in therapies, these numbers also change. The current 5-year survival statistic is based on patients diagnosed at least 5 years ago and may have received different therapies than are available today. As with all statistics, although the numbers define outcomes for the group, any individual's outcome has the potential for a wide range of variation.

All of this needs to be taken into consideration when interpreting these numbers for oneself.

Below is the statistics chart from the National Cancer Institute's SEER database.

Stage5-year survival rate
0100%
I100%
II93%
III72%
IV22%

These statistics are for all patients diagnosed and reported. Several recent studies have looked at different racial survival statistics and have found a higher mortality (death rate) in African-American women compared to white women in the same geographic area.

How to prevent breast cancer

There is no guaranteed way to prevent breast cancer. Reviewing the risk factors and modifying the ones that can be altered (increase exercise, keep a good body weight, etc.) can help in decreasing the risk.

Following the American Cancer Society's guidelines for early detection can help early detection and treatment.

There are some subgroups of women that should consider additional preventive measures.

  • Women with a strong family history of breast cancer need genetic testing such as HER2-Positive and BRCA Gene tests. Discuss this with a health care provider and meet with a genetic counselor who can explain what the testing can and cannot tell and then help interpret the results after testing.
  • Chemoprevention is the use of medications to reduce the risk of cancer. The two currently approved drugs for chemoprevention of breast cancer are tamoxifen (a medication that blocks estrogen effects on the breast tissue) and raloxifene (Evista), which also blocks the effect of estrogen on breast tissues. Their side effects and whether these medications are right for an individual need to be discussed with a health care provider.
  • Aromatase inhibitors are medications that block the production of small amounts of estrogen usually produced in postmenopausal women. They prevent reoccurrence of breast cancer but are not approved at this time for breast cancer chemoprevention.
  • For a small group of patients who have a very high risk of breast cancer, surgery to remove the breasts may be an option. Although this reduces the risk significantly, a small chance of developing cancer remains.

QUESTION

A lump in the breast is almost always cancer. See Answer

What research is the latest research on breast cancer? Is it worthwhile to participate in a breast cancer clinical trial?

Without research and clinical trials, there would be no progress in our treatment of cancers.

Research can take many forms, including research in the laboratory directly on cancer cells or using animals. Research can also be performed using patient volunteers.

Research that a patient can be involved in is referred to as a clinical trial. In clinical trials, different treatment regimens are compared for side effects and outcomes, including long-term survival. Clinical trials aim to find out whether new approaches are safe and effective.

Whether one should participate in a clinical trial is a personal decision and should be based upon a full understanding of the advantages and disadvantages of the trial. One should discuss the trial with a health care team and ask how this trial might be different from the treatment one would usually receive.

Someone should never be forced to participate in a clinical trial or be involved in a trial without full understanding of the trial and a written and signed consent.

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Medically Reviewed on 2/4/2020
References
Kroener, L., D. Dumesic, and Z. Al-Safi. "Use of fertility medications and cancer risk: a review and update." Curr Opin Obstet Gynecol May 22, 2017.

Salerno, K.E. "NCCN Guidelines Update: Evolving Radiation Therapy Recommendations for Breast Cancer." J Natl Compr Canc Netw 15(5S) May 2017: 682-684.

Shield, Kevin D., et al. "Alcohol Use and Breast Cancer: A Critical Review." Alcoholism: Clinical and Experimental Research Apr. 30, 2016.
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