Cancer can appear anywhere in the body, at any time. Wherever the cancer begins is considered the primary site of the cancer, and cancer found anywhere else in the body is secondary, or metastatic, cancer. When dealing with the combination of lung cancer and brain cancer, one will be the primary and one the secondary cancer. Primary brain cancer is not very common, but secondary brain cancer is. Brain cancer may metastasize from anyplace in the body, but some of the more common sites that can cause secondary brain cancer are the breasts, kidneys, colon, skin and lungs.
When a person has both lung cancer and brain cancer, it is most likely that it began as primary lung cancer and spread to the brain. Once cancer has spread beyond the original site, it is probable that it has spread to other parts of the body as well. This means that in many cases a person will not only have lung cancer and brain cancer, but also may have secondary breast cancer, colon cancer, bone cancer, liver cancer or many other types of cancer as well. In this case treatment must be very aggressive, usually involving a combination of surgery, chemotherapy and radiation.
Cancer is diagnosed in a variety of ways, usually by a combination of methods. A case history of the patient is extremely important, as it gives the doctor insight into what the problem could be and where to start looking. Blood tests can be used to further narrow the possible sources of such problems as weight loss, dizziness, breathing problems, eye troubles, headaches and other unexplained difficulties. Imaging tests can be used to identify specific problems, especially tumors. Such tests include magnetic resonance imaging (MRI), x-rays, positron emission tomography (PET) scans, and computerized tomography (CT) scans.
After a diagnosis of cancer, it is important to determine if the cancer exists anywhere else in the body, as this affects the specific treatment that is used. When a patient has both lung cancer and brain cancer, it is probable that the lung cancer is the primary cancer, and the brain cancer is actually metastatic lung cancer, or lung cancer that has moved to the brain. This affects the choice of chemotherapy drugs, as secondary cancer has the cell and tumor type of the original cancer. Whatever the determination, the earlier treatment can begin the better the prognosis for the patient.