Breast cancer begins in the breast tissue and in many cases, it will be detected and treated before it reaches any other parts of the body. However, if the cancer begins to spread it can affect nearby tissue and organs, including the lungs.

Where Does Breast Cancer Spread?

When cancer isn’t detected early and eliminated by surgery or other treatments, cancer cells can escape from the tumour and spread to other parts of the body. Breast cancer cells can spread to any part of the body, but they are most often found in nearby areas, particularly the lymph nodes under the armpit or in the throat, the lungs, or the surrounding tissue. Breast cancer is also more likely to spread to the liver, bones, or brain, although the cells can reach any part of the body as they can travel in the bloodstream or lymph network.

It can take months or even years for breast cancer to spread to other parts of the body, so if the cancer is spotted early it may be possible to eliminate it before this happens. However, sometimes the signs of breast cancer are missed until it has already spread or metastasised and started causing symptoms in other parts of the body, such as the lungs.

Breast Cancer in the Lungs

Breast cancer can spread into the lungs or it can affect the space around the lungs, forming tumours in between the lungs and the chest wall (the pleural space). The cancer can cause too much fluid to build up in this space, making it harder for the lungs to expand and do their job.

If the lungs or surrounding area are affected by breast cancer then it can cause symptoms such as:

• chest pain
• shortness of breath
• a persistent cough
• loss of appetite or unexplained weight loss

Although these symptoms can be similar to those caused by lung cancer, the condition will still be diagnosed as breast cancer if this is where the problem started. The type of cancer is determined by the type of cells that became cancerous, as this can affect their nature and the treatment options that are available. For example, breast cancer cells often have a receptor known as HER2 that can be targeted by certain therapies. The receptor will still be present even if the cancer spreads to other parts of the body, such as the lungs, so these therapies can work on breast cancers in different parts of the body.

Therapies can help to slow the growth of cancer that has spread beyond the breasts, but it is not usually possible to eliminate all of the cancer cells once it has metastasised. However, treatments are always improving and growing numbers of people are living for longer after their breast cancer has spread. Treatments can also help to relieve the symptoms of advanced breast cancer in order to ensure the best quality of life. For example, you may need to see a respiratory specialist to tackle symptoms such as breathlessness as well as a breast cancer specialist.