Moments That Count has been developed and funded by Novartis Pharmaceuticals UK Limited and is intended for a UK general public audience.

Understanding types of cancer

The difference between primary breast cancer (PBC) and secondary breast cancer (SBC)

Most cancers start in one place. The place where a cancer starts is called the primary site. For example, if you have cancer that started in the breast, you have primary breast cancer.

When the cancer has spread to a new location, this location is known as the secondary site. So, if your breast cancer has spread to the lungs, your secondary site is the lung, and you have secondary breast cancer (also known as advanced, metastatic or stage 4 cancer).1

If you would like to learn more about the stages of breast cancer, click the button below to read our guide.

how primary breast cancer spreads
Breast cancer progression

How primary breast cancer spreads

Cancers can spread around the body if left untreated, and in some cases, even if the patient is currently receiving a breast cancer treatment. When the cancer cells break away from where they first formed, they travel through the blood or lymphatic system (a network of tubes which collect fluid as part of the immune system) and reach the lymph nodes, forming new tumours in other parts of the body. This is known as metastasis.

The most common places primary cancer can spread to are:2

icon group
Signs it could have spread

Red flag symptoms

Take a moment to learn about the symptoms you might experience if the cancer has spread to another area in your body. If you experience these symptoms, you should contact your cancer specialist as soon as possible.

General symptoms

There are some general symptoms, which may differ from person to person and can include:3

•  Feeling more tired than usual
•  Loss of appetite
•  Feeling generally unwell for no obvious reason

These symptoms can also be associated with a wide range of other conditions, so if you experience any of them you should let your healthcare professional know. You should always let them know if you develop any new symptoms, especially if they last more than 1 or 2 weeks.


The most common symptom of secondary breast cancer in the bones is an ongoing ache in the affected bone/bones. If you are experiencing pain when you move around, or you are having difficulty sleeping because of the pain, this could be due to the cancer having spread to the bones.4

Too much calcium

If the cancer has spread to a bone, it can cause damage. If this happens, the bone can release calcium into the bloodstream. A high level of calcium in the blood is known as hypercalcaemia which can cause the following symptoms:4

  • Feeling tired, nauseous, dehydrated and/or weak
  • Passing more urine than usual
  • Constipation
  • Feeling confused

A healthcare professional can detect elevated levels of calcium in the bloodstream with a blood test before any symptoms develop.

A break in the bone

If the bone is damaged by cancer over time, it could become weaker and eventually lead to a break or a fracture. In most cases treatment will begin before the bone weakens enough to break.4

Pressure on the spinal cord

Cancer that has spread to the bones of the spine can cause pressure on the spinal cord. This is known as spinal cord compression. The symptoms can include:4

  • Unexplained pain in the back, around the chest and neck areas or down the arms and legs
  • Numbness or pins and needles in toes, fingers or buttocks                        
  • Unsteadiness or difficulty walking
  • Problems controlling your bladder or bowel.


Spread of breast cancer to the lung(s) (lung metastasis) can be symptomless. However, symptoms can include discomfort in the lung, shortness of breath, coughing up blood and a persistent cough. Other signs include:4,5

  • Pleural effusion – build-up of excess fluid between the layers of tissue outside the lungs, which cause pain on breathing, cough, or shortness of breath
  • Wheezing – whistling or rattling sound in the chest
  • Pain in the lung


If the cancer has spread to the liver, it is likely that you will feel some pain or discomfort around the area of the liver. The liver sits under the lower ribs on the right side of the abdomen. Other symptoms can include:4,6
General feelings of unwellness

  • Loss of appetite
  • Fatigue
  • Bloating
  • Jaundice

Secondary breast cancer in the liver can cause a build-up of bile in the blood. This is known as jaundice. Symptoms of jaundice can include yellowing of the skin and the whites of the eyes, and itchy skin.
Sometimes liver metastasis might be found incidentally via abnormal liver function tests, and the patients could be completely asymptomatic.


Secondary breast cancers can sometimes spread to the skin. Known as skin secondaries or metastases, it can develop on or just below the skin. This can happen to women who already have secondary breast cancer.

Possible symptoms of secondary cancer that has spread to the skin include:4

  • A firm painless lump on the skin
  • Many lumps of different size on the skin
  • Inflamed skin (areas of redness, swelling, or irritation)
  • Bleeding, pain or infections

Skin secondaries can appear near the area of the primary cancer, for example on the skin around a scar or around the chest. They have also been known to develop on the scalp, neck, back and upper limbs.

A variety of treatments can be used to treat skin secondaries.


The symptoms experienced with brain metastasis may be dependent on which part of the brain the cancer has spread to. The symptoms can include:4,7

  • Weakness in the muscles, numbness and feeling unsteady (ataxia)
  • Seizures or fits
  • Mood and personality changes
  • Sensory changes
  • Memory problems


Sometimes, breast cancer cells spread to tissue that covers the brain and spinal cord (meninges). Doctors call this meningeal metastases or carcinomatous meningitis. It causes symptoms similar to a secondary cancer in the brain.4

Risk of recurrence

Share your symptoms to receive treatment sooner

You understand your body better than anybody else, which means healthcare professionals will only know something is wrong if you let them know. If you feel any new symptoms, it is very important that you let your doctor or nurse know as soon as you notice them, as this might mean the cancer has recurred or returned as secondary.

jo taylor walking
You know you best

Make your next appointment count

Your healthcare team is your best resource throughout your treatment. Talk openly and often with them about your doubts, questions and concerns. We have developed a guide to support you in having these conversations with some tips to help you find the information you need.

appointment guide

Learn more about...

breast cancer diagnosis

Breast cancer diagnosis

Learn more about the process and techniques used to diagnose breast cancer.

biomarkers guide

Biomarkers guide

Read the biomarkers guide to understand the role they play in treatment options.

terminology guide

Terminology guide

Use our glossary of medical terminology so you're not left in the dark at appointments.


  1. Northern Ireland Cancer Network. What is the difference between primary and secondary cancer? Available online at: [Last accessed: July 2023]
  2. Macmillan Cancer Support. Secondary Breast Cancer. Available online at: [Last accessed: July 2023]
  3. Macmillan Cancer Support. Symptoms of Secondary Breast Cancer. Available online at: [Last accessed: July 2023]
  4. Macmillan Cancer Support. Understanding secondary breast cancer. Available online at: [Last accessed: July 2023]
  5. Breast Cancer. Lung metastasis: Symptoms and Diagnosis. Available online at: [Last accessed: July 2023]
  6. Breast Cancer. Liver metastasis: Symptoms and Diagnosis. Available online at: [Last accessed: July 2023]
  7. Breast Cancer. Brain metastasis: Symptoms and Diagnosis. Available online at: [Last accessed: July 2023]

UK | September 2023 | 124190-2





Moments That Count has been developed and funded by Novartis Pharmaceuticals UK Limited. It has been created in collaboration with secondary breast cancer patients whose knowledge and insights have informed the content and direction for the campaign.

This website is part of a programme that is funded by Novartis Pharmaceuticals UK Limited. Novartis Pharmaceuticals UK Limited is a private limited liability company registered in England and Wales under number 119006. Registered office 2nd Floor, The WestWorks Building, White City Place, 195 Wood Lane, London, W12 7FQ. Use of this website is governed by our Terms of Use and the Cookies and Privacy Policy.

Reporting side-effects
If you get side effects with any medication you are taking, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in the information leaflet that comes in the pack. You can report side effects via the Yellow Card Scheme at By reporting side effects, you can help provide more information on the safety of your medication.

©2024 Novartis Pharmaceuticals UK Ltd - UK | January 2024 | 124182-3 This site is intended for a UK general public audience.