What is Breast Cancer?

On this page we cover:


A note on terms:

Everyone has breast tissue and people of all genders can get breast cancer. To be clear and consistent, we use the word ‘breasts’ in our health information, rather than boobs, pecs or chest. When we say breasts, we mean the tissue from your rib cage up to your collarbone and armpits, including your nipples.

What is Breast Cancer?

Cancer is a condition that causes cells in the body to grow uncontrollably. These cells form growths, called tumours. Breast cancer is cancer that forms in breast tissue. Everyone has breast tissue – people of all ages, races and genders. In the UK, 1 in 7 women and about 1 in 100 men will be diagnosed with breast cancer in their lifetime. If breast cancer is diagnosed early, it is curable. That is why at CoppaFeel! we want to educate you on the signs and symptoms of breast cancer, and empower and encourage you to regularly check your chests.

What even are Boobs?

When we talk about ‘boobs’ we mean whatever you call your breast tissue. That might be breasts, chest, boobs, or pecs! Breast tissue goes all the way up to your collarbone and under your armpit. To understand breast cancer, it helps to understand a bit about breasts. Breast tissue is different in women and men, but there are some similarities. For example, all breast tissue contains fat and all breast tissue contains lymph vessels.

Your Stories

Read more about real life stories of breast cancer on our Brazette, from the young people who have experienced a diagnosis.

Read More

Primary Breast Cancer

Primary breast cancer is breast cancer that hasn’t spread beyond the breast or the lymph nodes (glands in your armpits). There are several different types of primary breast cancer, and it can be diagnosed at different stages. Breast cancer is staged from stage 1 to stage 4. Primary breast cancer is different from secondary breast cancer. Secondary breast cancer is when breast cancer has spread to other parts of the body. We have more information about secondary breast cancer below.

Secondary Breast Cancer

Secondary breast cancer is when breast cancer spreads from the breast and lymph nodes (glands in your armpits) to other parts of the body. When cancer spreads to other parts of the body, it can form another tumour. This is called secondary cancer. Secondary cancer is also called:

  • Stage 4 cancer
  • Metastatic cancer
  • Metastasis or metastases
  • Advanced breast cancer

Breast cancer can spread to many parts of the body. The most common parts are:

  • Bones
  • Lungs
  • Liver
  • Brain

If breast cancer spreads to other parts of the body, it is still called breast cancer. For example, breast cancer that spreads to the bone is called secondary breast cancer in the bone.

Secondary breast cancer can be treated, but not cured. Treatment for secondary breast cancer helps with symptoms and stops the cancer from spreading further. If someone has secondary breast cancer, they will always have it, but they can live a healthy life for a long time. Our friends at Breast Cancer Now have more information about secondary breast cancer here.


DCIS means Ductal Carcinoma in Situ. It is the earliest form of breast cancer. DCIS is when the cancer cells are contained within the lobule or duct where they first formed. In DCIS, the cancer cells still remain in the lobule or ducts – this is known as ‘in situ’. DCIS might also be called:

  • Non-invasive breast cancer
  • Pre-invasive breast cancer/pre-cancerous change
  • Intra ductal breast cancer
  • Ductal intraepithelial neoplasia (DIN)
  • Stage 0 breast cancer

Invasive breast cancer starts as DCIS, but not every DCIS will turn into invasive breast cancer. We don’t know which DCIS cells will become invasive breast cancer, and which won’t. So, most cases of DCIS are treated because it can become invasive breast cancer in the future. About 12 in 100 breast cancers are DCIS. Because it is an early form of breast cancer, it can be cured with treatment.

It is always important to contact your GP if you notice any breast changes at all. The earlier breast cancer is found, the better.

This information was published in April 2021. We will revise it in 2024.


Signs and Symptoms

Find out more about the signs and symptoms of primary breast cancer below.

Find out more