Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer that is more likely to recur and spread than other forms of breast cancer. With treatment, about 60% of people with this cancer will continue to live disease-free.

TNBC typically has a less positive outcome than other types of breast cancer, as fewer treatment options are available.

About 10–15% of all breast cancers are triple-negative. This type of breast cancer is more common among:

  • females
  • people younger than 40 years
  • Black people
  • people with BRCA1 and PALB2 mutations

In particular, TNBC disproportionately affects non-Hispanic Black females. About 21% of the breast cancers that affect these individuals are triple-negative. The rate is double that of other racial and ethnic groups. Research shows that African American people are also nearly twice as likely to die of the disease.

A 2019 study found that roughly 40% of people with stage 1 to stage 3 TNBC will see their cancer return after standard treatment. The remaining 60% will have long-term survival without recurrence.

The outcomes of treatment vary. About 42% of those with this form of cancer will have a rapid relapse after standard treatment. This recurrence typically occurs within the first 2–3 years following the initial diagnosis.

It is not currently possible to predict who will experience a relapse in their cancer, even if they have had intensive chemotherapy.

On average, 77% of people with this cancer will live 5 years after diagnosis compared with individuals who do not have this cancer. This survival rate is 8–16% lower than that of hormone receptor-positive breast cancer, in which the cancer cells have estrogen receptors, progesterone receptors, or both.

Triple-negative breast cancer can recur in various areas of the body and at local, regional, and distant levels:

  • Local means that the cancer remains in the breast and has not spread.
  • Regional is when the cancer spreads from the breast to lymph nodes and other structures located nearby.
  • Distant refers to cancer that has spread far from the breast to other organs, such as the liver or lungs.

A 2017 study examined the patterns of recurrence among 1,930 people with TNBC. The researchers divided the patients into two age groups: 15% were younger than 40 years at the time of their diagnosis, and 85% were 40 years or older.

The researchers found only a small difference between the two groups in terms of recurrence of the cancer on the local level: 6% of those under 40 versus 5% of those aged 40 or above.

The same study found that the rate of regional recurrence was 2% for both groups.

The axilla, the area where the shoulder meets the arm, accounted for the majority of the regional recurrence sites. Of the participants with regional recurrence, 3 out of 5 experienced it there, regardless of their age.

Among the participants under the age of 40, 17% experienced distant recurrence. The percentage was lower among those aged 40 or older, at 12%.

The percentages of people experiencing distant recurrence at multiple sites were similar in both age groups: 36% in the younger group and 37% in the older group.

People who experience recurrent breast cancer may experience a range of symptoms, which may vary depending on whether the recurrence is local, regional, or distant.

Individuals who experience localized recurrent breast cancer may experience:

  • skin swelling in the breast or around it
  • discolored skin on the breast or around it
  • new lumps in the breast
  • new swelling or pulling of the skin at the site of the lumpectomy
  • new areas in the breast that seem unnaturally firm
  • changes to the nipple, such as flattening
  • thickening either on or near the scar from the mastectomy
  • bumps on the chest wall, either under or on the skin

Those who experience a regional recurrence of breast cancer may have the following symptoms:

  • difficulty swallowing
  • a loss of feeling in the shoulder or arm
  • constant pain in the shoulder, arm, or chest
  • a lump near the breastbone or collarbone, or in the lymph nodes located under the arm
  • swelling in the lymph nodes under the arm, near the collarbone or breastbone
  • swelling in the arm on the same side as the original site of the breast cancer

A distant recurrence of breast cancer may cause a variety of symptoms depending on where the cancer appears. Possible symptoms include:

  • numbness
  • weakness
  • a persistent dry cough
  • a lack of appetite
  • problems with the vision
  • severe headaches
  • constant nausea
  • unintentional weight loss
  • pain in the bones
  • confusion
  • difficulty with balance
  • seizures

Although research suggests that about 40% of people who receive treatment for stage 1 to 3 of TNBC will experience a recurrence, 60% will continue to live a disease-free life.

The American Cancer Society gives 5-year relative survival rates based on whether the cancer is local, regional, or distant. This rate shows the likelihood of a person with this cancer living for 5 years after diagnosis compared with people who do not have this cancer.

For TNBC that remains local, the 5-year relative survival rate is 91%. For regional TNBC, it is 65%, and for distant TNBC, it is 12%. Combining the stages, the overall 5-year relative survival rate is 77%.

It is possible for people with TNBC to live long lives even following a diagnosis. In one case study, a woman in her late 50s who experienced recurrent TNBC that spread to her lungs, liver, and bones was still alive 15 years later.

Triple-negative breast cancer is an aggressive, fast-growing form of breast cancer that is more likely than other forms of breast cancer to recur. About 40% of people with stage 1 to 3 TNBC will experience a recurrence after treatment. However, many of those with TNBC will live long, disease-free lives.

The overall 5-year relative survival rate across all stages of the disease is 77%. It is important to remember that the survival statistics depend on the stage of cancer at the time of diagnosis. As research and treatment continue to advance, the survival rate will also improve over time.