A person diagnosed with lung cancer is said to have reached stage IV or metastatic stage when the lung cancer cells breaks away from the tumor and travels to various parts of body through blood and lymph system. It is even possible that the lung cancer has reached the metastatic stage even before it is diagnosed. This is because the symptoms do not develop when the lung cancer is already present in the body. This is the reason why it is common for cancer to metastasize before it is diagnosed.

One important thing to keep in mind is that, even though the cancer may have spread to different locations in the body, it will still be named after the part of the body where it is was originated.

Lung cancer, when reached metastatic stage usually spreads into adrenal glands, bones, brain, and the liver. Metastatic lung cancer is completely different from recurrent lung cancer. Lung cancer that has reoccurred has to be treated the same way it was treated when it first occurred. Since, metastatic lung cancer has spread to a completely different part of the body, it will be treated differently.

Generally, lung cancer that has spread to the different part of the body will be treated the same way as it is treated as its original place of occurrence.

Most of the cases of metastatic lung cancer that have spread to the liver are treated using drug therapy.

The metastatic lung cancer that has spread to the brain is usually treated with radiation therapy. The radiation therapy is done majorly in two different ways:
External Beam Radiation Therapy (EBRT) : This therapy delivers high doses of radiation to lung cancer by exposing the body to a beam of high intensity X rays using various machine based technology.

Brachytherapy: Brachytherapy is a type of internal radiation therapy that delivers high doses of radiation from the radioactive implants that are placed closed to or inside the tumor in the body.
Other treatments include chemotherapy using steroids or other medications. Surgery could also be an option but in very specific cases.

If diagnosed with a metastatic lung cancer, consult an oncologist, who would suggest the best option to treat metastatic lung cancer.