What is stage 3 breast cancer?

Hearing you have stage 3 breast cancer can bring many questions – about your diagnosis, survival, treatments, and more.

First, stage 3 breast cancer means your cancer has spread beyond the tumor and has possibly gone to lymph nodes and muscle, but has not spread to nearby organs.

Doctors divide 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.

Stage 3 breast cancer is considered advanced cancer. But, advanced doesn’t mean untreatable. Your treatment options and outlook will depend on a variety of factors, inducing cancer subtype, individual health, age, and how your body responds to treatment.

Because stage 3 breast cancer has spread outside the breast, it’s harder to treat than early stage breast cancer. With aggressive treatment, stage 3 breast cancer is curable, but 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.

No matter what 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 your treatment and individual outlook.

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

In addition to cancer stage, doctors will determine the tumor grade and tumor 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 your treatment and outlook will vary depending on which subtype of breast cancer that you have. Subtypes include HER2-positive, ER-Positive, and triple-negative breast cancer.

Another way a doctor may describe stage 3 breast cancer is if it is operable or non-operable. 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, but surgery isn’t the right option because doctors feel they can’t remove enough cancerous cells. Sometimes, treating the cancer with radiation or chemotherapy medications to shrink the tumor can make cancer operable at a later time.

Treatment options for stage 3 breast cancer may include:

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

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

Survival rates can be confusing and don’t reflect your individual picture. The relative five-year survival rate for stage 3 breast cancer is 72 percent. This means that out of 100 people with stage 3 breast cancer, 72 will survive for five years.

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

In comparison, the five-year relative survival rate for both stage 0 and stage 1 breast cancer is nearly 100 percent. For stage 2 breast cancer, it’s 93 percent, and for stage 4, it’s 22 percent.

Studies linking breast cancer survival rates to age at diagnosis have been conflicting.

One 2015 Swedish study of 4,119 women with breast cancer found that survival rates for breast cancer are most impacted by age when a woman is over age 80 at diagnosis.

Women who were under age 40 at diagnosis were also found in this study to have a poor prognosis.

Women over 80 may have a higher mortality rate than younger women because their breast cancer has spread further by the time they are diagnosed. In addition, women in this age group may not be considered as ideal candidates for surgery as younger women.

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.

Find support from others who are living with breast cancer. Download Healthline’s free app here.