Hearing you or a loved one has stage 3 breast cancer can lead to many questions — about diagnosis, survival, treatments, and more.

The first thing to know is that stage 3 breast cancer means the cancer has spread beyond the tumor. It has possibly gone to lymph nodes and muscle but hasn’t spread to nearby organs.

Doctors have previously divided stage 3 into more specific categories (3A, 3B, and 3C) and the cancer subtype, meaning which type of breast cancer you have. The breast cancer type describes how a cancer grows and what treatments are likely to be most effective.

In 2018, the American Joint Committee on Cancer (AJCC) released updated staging definitions for this type of breast cancer that include biological factors such as tumor grade to better clarify the situation.

Stage 3 breast cancer is considered a locally advanced but curable cancer. Your treatment options and outlook will depend on a variety of factors.

Survival rates can be confusing. Remember that they don’t reflect your individual circumstances.

The relative 5-year survival rate for stage 3 breast cancer is 86 percent, according to the American Cancer Society. This means that out of 100 people with stage 3 breast cancer, 86 will survive for 5 years.

But this figure doesn’t consider breast cancer characteristics, like grade or subtype. It also doesn’t distinguish between people with stage 3A, 3B, and 3C.

In comparison, the relative 5-year relative survival rate for stage 0 breast cancer is 100 percent. For stages 1 and 2, it’s 99 percent. For stage 4, the survival rate drops to 27 percent.

The life expectancy for people with breast cancer is improving, according to the American Cancer Society. It points out that current survival rates are based on people who were diagnosed and treated at least 5 years ago — and treatments have advanced over that time.

Your life expectancy with stage 3 breast cancer depends on several factors, such as:

  • your age
  • your overall health
  • the response to treatment
  • the size of the tumors

You should talk with your doctor about how these factors may apply to you.

Because stage 3 breast cancer has spread outside the breast, it can be harder to treat than earlier stage breast cancer, though that depends on a few factors.

With aggressive treatment, stage 3 breast cancer is curable; however, the risk that the cancer will grow back after treatment is high.

Doctors further divide stage 3 cancer into the following stages:

Stage 3A

In stage 3A breast cancer, one of the following applies:

  • No tumor is in the breast or the tumor of the breast is any size. Cancer is found in four to nine nearby lymph nodes.
  • The tumor is larger than 5 centimeters. Small clusters of cancer cells are also found in nearby lymph nodes.
  • The tumor is larger than 5 centimeters. Cancer is also found in up to three nearby lymph nodes under your arm or near your breastbone.

Stage 3B

In stage 3B breast cancer, a tumor of any size is found. Cancer cells are found in the chest wall or skin of the breast. These areas may appear inflamed or have ulcers. In addition, one of the following applies:

  • Up to nine nearby lymph nodes are involved.
  • The cancer has spread to the lymph nodes near the breastbone.

Stage 3C

There could be a tumor of any size or no tumor at all. In addition, cancer has invaded the chest wall or skin of the breast. There’s inflammation or ulcers of the skin. One of the following also applies:

  • Cancer is found in 10 or more of the underarm lymph nodes.
  • Cancer is found in the lymph nodes reaching up to the collarbone.
  • Cancer is found in the lymph nodes under the arm and near the breastbone.

In addition to cancer stage, doctors will determine the tumor grade and subtype.

Tumors are graded on a scale of 1 to 3, based on how abnormal the cells appear compared to normal cells. The higher the grade, the more aggressive the cancer, meaning that it tends to be growing quickly.

The subtype is important because treatment and outlook will vary depending on which subtype of breast cancer that you have. Subtypes include:

The TNM system for staging breast cancer

The AJCC’s addition of the letters T, N, and M for anatomic breast cancer staging adds more information to a breast cancer diagnosis. Here’s what they mean:

  • T (tumor): The tumor grade shows a higher number for a larger size or density.
  • N (nodes): Nodes refers to lymph nodes and uses the numerals 0 to 3 to give information about how many lymph nodes are involved in the cancer.
  • M (metastasis): This refers to how the cancer has spread beyond the breast and lymph nodes.

The AJCC also added clarifications in staging for ER, PR, and HER2 expression and also genetic information.

Ultimately, this means someone diagnosed with stage 3 breast cancer can receive more information from their breast cancer staging than ever before.

No matter the stage, the best source of information about your individual outlook is your own oncology team.

Make sure you understand your breast cancer stage and subtype so that you can better understand treatment options and individual outlook.

Getting the right treatment and the support you need can help you navigate the challenges of being diagnosed with stage 3 breast cancer.

Another way a doctor may describe stage 3 breast cancer is if it’s operable or inoperable. This will determine further treatments.

If a cancer is operable, this means a doctor believes most or all of the cancer can be removed with surgery.

Inoperable cancer is still treatable with systemic therapy, but surgery isn’t the right option because doctors feel they can’t remove enough cancerous cells.

Treatment options for stage 3 breast cancer may include:

  • Surgery: known as a mastectomy, to remove cancerous tissue and also to remove lymph nodes
  • Hormone therapy: to slow or stop the growth of cancerous cells, if hormones are driving their growth
  • Chemotherapy: involves taking medications to kill fast-growing cancer cells
  • Targeted therapy: uses your genes to attack cancer cells without harming healthy cells

Your doctor may also recommend a combination of two or more treatments.

Although stage 3C breast cancer is defined as either operable or inoperable, an inoperable diagnosis doesn’t necessarily mean that it can’t be treated.

The term “inoperable” may mean that all the cancer in the breast and surrounding tissue can’t be removed through simple surgery. When breast cancer is removed, a rim of healthy tissue around the tumor, called a margin, is also removed.

For breast cancer to be successfully removed, there needs to be healthy tissue in all margins of the breast, from your clavicle down to a few inches below the breast mound.

It is possible for inoperable breast cancer to become operable following a treatment to shrink the cancer.

It’s natural to want to know your outlook, but statistics don’t tell the whole story. Your breast cancer type, overall health, and many more factors beyond your control may affect treatment outcomes.

Establishing open communication with your treatment team can help you best assess where you are in your cancer journey.

Support groups can be a great source of comfort as you navigate your diagnosis through your treatment and beyond. Your doctor’s office or hospital can offer some suggestions and resources in your area.

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