Metastatic cancer occurs when cancer spreads from its original location (primary tumour) to a new part of the body. Lung (pulmonary) metastases occur when a cancer spreads to the lung from its primary site. Lung metastases are different from a cancer that starts in the lung (called primary lung cancer). The lungs are among the most common places where cancer can spread.
Lung metastases only develop if a person already has cancer. Almost any type of cancer can spread to the lung. Cancers that typically spread to the lung include:
Occasionally, cancer spreads to the lung but the original location of the cancer in the body is not known. This is called cancer of unknown primary (CUP).
Lung metastases can occur anywhere in the lung. Most people will have multiple lung metastases. Single lung metastases are uncommon and occur in only a small number of people with cancer. Single lung metastases occur most often with sarcomas.