Cancer that starts in the lungs is called primary lung cancer. The lungs are common sites for metastasis of other types of cancers, which start elsewhere in the body, such as breast cancer or colon cancer. That is called secondary lung cancer. It is important to know whether the cancer started in the lungs (primary) or has spread to the lungs (secondary). Cancer cells will be different in primary and secondary lung cancer, so the treatment will depend on the type of cancer. For eg. cancer that…
