Each lung contains a branched structure made up of airways called bronchi or bronchioles, as well as alvioli--small air sacs that facilitate oxygen transfer into the blood. Lung cancer may develop within the bronchi, bronchioles or air sacs, and interfere with normal breathing. In advanced stages, lung cancer cells gain the ability to migrate to distant tissues, a process called metastasis. Several types of lung cancer have the ability to metastasize, and to form secondary tumors within the brain, which ultimately can prove fatal.
Small Cell Cancer
Small cell lung cancer, also called oat cell cancer, or combined small cell carcinoma, readily metastasizes to the brain. Small cell lung cancers account for bout 15 percent of all lung cancer cases. Almost all small cell lung cancer cases are linked to smoking, according to Medline Plus. Small cell lung cancers are typically aggressive, and have often metatasized to other tissues, such as the brain, by the time they are diagnosed. Upon diagnosis, small cell lung cancer patients undergo MRI imaging of the brain to check for brain metatastasis. If the radiologist finds brain metastases, patients may undergo a combination of radiation and chemotherapy treatment to help slow or stop cancer growth.
Squamous Cell Carcinoma of the Lung
Squamous cell carcinoma of the lung also commonly spreads to the brain. About 15 percent of squamous cell lung cancer patients develop brain metastases, according to Harvard University. Squamous cell lung cancer originates from flattened epithelial cells that line the air sacs of the lungs. During cancer development, the cells begin to proliferate and form tumors in the center of the lungs. Squamous cell lung cancer patients with secondary brain tumors often develop multiple tumors throughout the brain. Secondary cancer growth can affect a number of neurological functions, leading to personality changes, defects in co-ordination and movement or visual disturbances. In some cases, patients with brain metastases may receive chemotherapy to help slow cancer growth in the brain. They may receive palliative therapy to ease discomfort associated with cancer growth.
Adenocarcinoma of the Lung
Adenocarcinoma is the most prevalent type of lung cancer. It accounts for about 40 percent of lung cancer cases, according to the BC Cancer Agency in Canada. Patients with adenocarcinoma typically develop lung tumors close to the outside of the lungs. Advanced cases of adenocarcinoma of the lung readily spread to brain tissue. Harvard University says that adenocarcinoma patients typically develop multiple secondary brain tumors that affect brain functioning. Following diagnosis, adenocarcinoma patients may receive chemotherapy or radiation therapy to slow or stop cancer cell growth and slow cancer progression.
