Secondary breast cancer explained

Though there is growing awareness of breast cancer, whether through the media, charity campaigns or the experiences of those around us, secondary breast cancer remains much less widely discussed or understood. Whether you have received this diagnosis yourself, are currently living with primary breast cancer, or you know someone with secondary breast cancer, it can be confusing and frightening to try and understand what this means.

Here, we bring together information on the ‘whats’ and ‘whys’ of secondary breast cancer.

What is secondary breast cancer?

Primary breast cancer refers to cancer cells which grow and remain in the breast. Secondary breast cancer describes the spread of cancer cells from the breast (the ‘primary’ cancer) to other parts of the body. These cells travel via the blood or lymphatic system (a network of vessels around the body that help to fight infection and to get rid of toxins & waste). The most common places for breast cancer to spread to are the bones, lungs, liver or brain. Some less common places include the skin and areas of the abdomen (stomach).

When breast cancer spreads to a different area of the body, for example the liver, this is secondary breast cancer in the liver. This is not the same as cancer which begins in the liver i.e. liver cancer.

Lots of different words or phrases are used to describe the process of breast cancer spreading to other parts of the body, which can be very confusing. These all refer to the same thing;

  • Secondary breast cancer
  • Secondaries or secondary tumours
  • Metastatic breast cancer or metastases
  • Advanced breast cancer
  • Stage 4 or stage IV breast cancer

At present, there is no cure for secondary breast cancer. This means that there is no treatment able to remove or destroy all of these cells. However, there are lots of treatments that have the potential to control the cancer and the symptoms you might experience.

Why does secondary breast cancer develop?

Treatment for primary breast cancer aims to destroy all of the cancer cells. However, it is possible for some of these cells to escape treatment and be left behind in the body.  Over time, often years later, these cells may spread and grow in other parts of the body.

For some women, secondary breast cancer is the first diagnosis they receive. This is referred to as ‘de novo’ secondary breast cancer. This means that the cancer cells that started in the breast spread to another part of the body before they were able to be detected or to cause symptoms in the breast.  

What to ‘look out’ for: Signs & symptoms of secondary breast cancer

Symptoms of secondary breast cancer can vary between different patients, since they will depend on where exactly in the body the cancer has spread.

Below are some common symptoms of secondary breast cancer.

It is important to remember that lots of these symptoms may also be caused by other illnesses and won’t always be due to cancer. If you do experience any new or worrying symptoms, or symptoms that have carried on for some time, it is a good idea to discuss these with your doctor or nurse as soon as possible.

The following symptoms may be due to secondary breast cancer in the bones:

  • Aching in the bones
  • Pain in the bones which is usually worse at night
  • Broken or fractured bones

Commonly affected bones include the ribs, hips and back or spine.

It is important to remember that experiencing aching and pain after breast cancer doesn’t always mean that your cancer has spread to your bones. These may be due to many other normal illnesses and strains. Other things like hormone therapy, going through the menopause, arthritis, and the natural process of ageing can cause you to feel aches and pains.

The following symptoms may be due to secondary breast cancer in the lungs:

  • Feeling short of breath/difficulty catching your breath when you are resting
  • A cough that has continued for some time

The following symptoms may be due to secondary breast cancer in the liver:

  • Swelling and discomfort in the tummy
  • Yellow skin or yellow tinge in whites of the eyes
  • Persistent (won’t go away) itchy skin

The following symptoms may be due to secondary breast cancer in the brain:

  • Persistent headaches (headaches that won’t go away) that may be worse in the morning
  • Feeling or being sick
  • Feeling weak or numb in arms/legs
  • Dizziness/feeling ‘off balance’ or losing your balance
  • Changes in your mood or personality (these may be noticed by other people)
  • Fits or seizures

The following symptoms may be due to secondary breast cancer in the skin:

  • A rash that won’t go away
  • Swelling in or around the arm, hand or breast (known as ‘lymphoedema’)
  • Redness, warmth, weeping (signs of skin infection)
  • A painful area of skin
  • One or more small, firm lumps or ‘nodules’, which are usually painless

More general symptoms of secondary breast cancer may include losing your appetite or feeling ‘off’ your food, feeling much more tired than usual, losing weight without trying to, or feeling generally unwell for no other reason.  

It is always a good idea to discuss symptoms that have lasted more than a week or two with your doctor or nurse.

A good rule of thumb is to always let your doctor or nurse know if you have any of the following;

  • Symptoms that are new or worrying to you
  • Symptoms that you can’t explain
  • Symptoms that won’t go away

Breast Cancer Now have created the useful image below, which summarises the symptoms which may be a sign of secondary breast cancer.


‘Possible signs of secondary breast cancer’ Breast Cancer Now, 2019

Further information

When it comes to understanding your disease and being involved in decisions about your care, it can be difficult to know what you can ask and what you can expect of your oncologist. The European Society for Medical Oncology (ESMO) have put together a guide for patients living with advanced cancer, to help them to get the most out of discussions with their oncologist. Click on the button below to download this guide.

Page last updated: April 2020