To plan the best treatment, your doctor needs to know the type of lung cancer and the extent (stage) of the disease. Staging is a careful attempt to find out whether the cancer has spread, and if so, to what parts of the body. Lung cancer spreads most often to the lymph nodes, brain, bones, liver, and adrenal glands. Staging is very important because your treatment will depend on the stage of your cancer. Be sure to ask your doctor to explain your stage in a way that you understand. The Spread of Lung Cancer
At some point, cancer cells can break away and spread to other parts of the body in a process called metastasis. Lung cancer is a life-threatening disease because it often spreads this way before it is found.
One of the ways lung cancer can spread is through the lymph system. Lymph vessels are like veins, but they carry lymph fluid instead of blood. Lymph is clear fluid that contains tissue waste products and cells that fight infection. Lung cancer cells can enter lymph vessels and begin to grow in lymph nodes around the bronchi and in the area between the lungs.
When lung cancer cells have reached the lymph nodes, they are more likely to have spread to other organs of the body. Staging and decisions about lung cancer treatment are based on whether or not the cancer has spread to the nearby lymph nodes.
When cancer spreads from its original place to another part of the body, the new tumor has the same kind of cancer cells and the same name as the original cancer. For example, if lung cancer spreads to the liver, the cancer cells in the liver are actually lung cancer cells. The disease is metastatic lung cancer, not liver cancer. For that reason, it's treated as lung cancer, not liver cancer. Doctors call the new tumor "distant" or metastatic disease. Staging may involve blood tests and other tests:
- CT scan: CT scans may show cancer that has spread to your liver, adrenal glands, brain, or other organs. You may receive contrast material by mouth and by injection into your arm or hand. The contrast material helps these tissues show up more clearly. If a tumor shows up on the CT scan, your doctor may order a biopsy to look for lung cancer cells.
- Bone scan: A bone scan may show cancer that has spread to your bones. You receive an injection of a small amount of a radioactive substance. It travels through your blood and collects in your bones. A machine called a scanner detects and measures the radiation. The scanner makes pictures of your bones on a computer screen or on film.
- MRI: Your doctor may order MRI pictures of your brain, bones, or other tissues. MRI uses a powerful magnet linked to a computer. It makes detailed pictures of tissue on a computer screen or film.
- PET scan: Your doctor uses a PET scan to find cancer that has spread. You receive an injection of a small amount of radioactive sugar. A machine makes computerized pictures of the sugar being used by cells in the body. Cancer cells use sugar faster than normal cells and areas with cancer look brighter on the pictures.
- Bronchoscopy/EBUS: Bronchoscopy is a technique of visualizing the inside of the airways for diagnostic and therapeutic purposes. An instrument (bronchoscope) is inserted into the airways, usually through the nose or mouth. EBUS (Endobronchial Ultrasound) allows physicians to use ultrasound devices inside the airways and the lung for exploration of the structures of airway walls, the surrounding mediastinum, and the lungs.