Triple negative breast cancer: what it is, how it is treated and the outlook

Breast cancers are tested after a biopsy or surgery for three features: oestrogen receptors, progesterone receptors and the HER2 protein. Cancer Research UK explains that triple negative breast cancers are those whose cells have none of these. Breast Cancer Now adds that some breast cancers use oestrogen to grow (oestrogen receptor positive) and that some have higher-than-normal levels of HER2, which makes them grow more quickly.

The name matters because it determines which medicines can be used. Hormone therapies block or lower the effect of oestrogen, and HER2 treatments target the HER2 protein; neither helps a cancer that has neither feature. Breast Cancer Now says most people with triple negative breast cancer have invasive breast cancer of no special type, although medullary and metaplastic cancers are more likely than others to be triple negative.

Cancer Research UK says triple negative breast cancer develops more often in women under 40 and is more common in Black women than White women. Breast Cancer Now lists inherited altered BRCA genes (particularly BRCA1), being Black, not yet having reached the menopause and being under 40 as factors associated with higher rates.

Some women with triple negative breast cancer also have a mutation in the BRCA1 or BRCA2 genes. Everyone has these genes, which normally help to stop cells growing out of control; a fault in them can increase the risk of breast cancer. Breast Cancer Now says that people with triple negative disease are more likely to have an altered BRCA1 gene than people whose cancer is hormone receptor positive.

Cancer Research UK says the symptoms of triple negative breast cancer are similar to those of other breast cancer types. See a GP if you notice anything different or unusual about the look or feel of your breasts.

• A lump or thickening in the breast or armpit.

• A change in the size, shape or feel of the breast.

• Skin changes such as puckering, dimpling, a rash or redness.

• Fluid leaking from the nipple in a woman who is not pregnant or breastfeeding.

• A change in the position of the nipple.

Cancer Research UK says a GP refers you to a breast clinic if you have symptoms that could be due to breast cancer, and you may also be referred if a screening mammogram shows an abnormal area. You usually have a number of tests, including a mammogram, an ultrasound scan of the breast and a biopsy. The tissue sample is tested for hormone receptors and HER2, which is how the triple negative type is identified.

Doctors may also refer you for genetic testing to find out whether there is a change in a BRCA gene. Breast Cancer Now says that if you were diagnosed with triple negative breast cancer under the age of 60 you should be offered a referral to a specialist family history clinic or regional genetics clinic to discuss genetic testing regardless of family history, and that over 60 you may also be referred.

Cancer Research UK says the main treatments are surgery, chemotherapy and radiotherapy, and that the choice depends on where the cancer is, its size and stage, how abnormal the cells look (grade) and your general health. Breast Cancer Now says research has shown chemotherapy generally has a larger benefit for triple negative breast cancer than for oestrogen receptor positive breast cancer, and that it is often given before surgery, with drugs likely to include carboplatin or cisplatin.

Surgery may remove an area of the breast or the whole breast, and the surgeon usually checks the lymph nodes under the arm. After breast-conserving surgery you usually have radiotherapy to the rest of the breast. Cancer Research UK also says the doctor might suggest pembrolizumab, an immunotherapy given with chemotherapy before surgery and then on its own afterwards, and that bisphosphonates may be given to protect the bones. Which of these options is appropriate for you is a decision for your breast cancer team.

Breast Cancer Now explains that the risk of triple negative breast cancer coming back or spreading is higher than for some other types in the first few years, but that after around 5 years the risks are similar to, and may be lower than, other types. The overall picture depends on individual factors such as stage and grade, and your team is best placed to explain what applies to you.

Cancer Research UK says you have regular check-ups and mammograms after treatment, usually a mammogram every year for at least 5 years, and that you should contact your team if you notice a new symptom. Living with the worry of recurrence is common, and both charities offer information and support lines.

Diagnosis and treatment for triple negative breast cancer are provided through NHS breast services, with care planned by a multidisciplinary team and a clinical nurse specialist as the main contact. Some people also have a private consultation for a second opinion or faster scans; whichever route you use, treatment decisions should be coordinated with your NHS team so that follow-up and monitoring are consistent.