Lung metastases refers to cancer that has spread from another primary cancer area. Metastases means that the lungs are a secondary site. The location of the body where the cancer cells first originated is called the primary site of the cancer. Once cancer has metastasised from the primary site, to the lungs or elsewhere on the body, it is not curable and is considered Stage IV.
Cancers from other parts can spread to the lungs easily because blood from most parts of the body flow into the heart and the lungs before getting distributed to organs of the body. So, any cancer cell that finds its way into the bloodstream can stay stuck in the capillaries of the lungs. Lung cancer is the leading secondary cancer, or the leading site of metastases from other cancers.
Sites of Metastases
Cancers of the colon, breast, bladder, testicles or the prostate gland are the most common primary cancers with lung metastases. The cancer can spread to the lungs without giving any signs that it has spread, until cancer cells have begun to grow and multiply within the lining of the lungs.
A persistent cough is one potential symptom of lung metastases. When a cough continues for a long time and does not go away despite treatment, this can be a sign that primary cancer has spread. In advanced stages, the cough is likely to be accompanied by blood.
Since the lungs' functions are weakened by cancer cells, chest infections become common. These infections can happen with alarming frequency and gravity. They are characterised by a shortness of breath, coughing and fatigue.
Shortness of Breath
Shortness of breath or difficulty breathing is a sign of lung metastases. This is a byproduct of fluid build-up, which usually happens in the area between the chest of the wall and the lungs. Called pleural effusion, the condition gets aggravated when cancer cells irritate the pleura (the two sheets of tissue that cover the lungs). This causes insufficient air intake by the lungs. As a result, there is shortness of breath and a feeling of fullness. Decreased airflow into the lungs can also occur because the tumour can obstruct the flow of air. This condition can also cause wheezing.