What is Lung Cancer?
Lung cancer is the leading cause of cancer death in both men and women. Lung cancer is a cancer that usually starts in the lining of the bronchi (the medium-sized airways within lungs), but can also begin in other areas of your respiratory system, including the trachea (main breathing tube), bronchioles (smaller branches of the air passages), or alveoli (the tissue farther out in the periphery of the lung).
Lung cancers are believed to develop over a period of many months to years. Nearly all lung cancers are “carcinomas”—tumors that begin in the lining or covering tissues of an organ. The tumor cells of each type of lung cancer grow and spread differently, and the treatments of these various types differ to some extent. About 85 percent to 90 percent of lung cancers belong to the group called non-small cell lung cancer.
Types of Lung Cancer
- Non-Small Lung Cancer
Non-small cell lung cancer is much more common than small cell lung cancer. Surgery is a key component of therapy used far more often for non-small cell lung cancer than for small cell lung cancer. The three main kinds of non-small cell lung cancer are named for the type of cells in the tumor:
- Adenocarcinoma usually begins in the periphery of the lung and under the lining of the bronchi. It is the most common type of lung cancer in people who have never smoked.
- Squamous cell carcinoma is also called epidermoid carcinoma. It often begins in the bronchi near the middle of the lungs.
- Large cell carcinomas are a group of cancers with large, abnormal-looking cells. These tumors may begin anywhere in the lungs.
- Small cell lung cancer
Small cell lung cancer is a form of neuroendocrine cancer that often grows rapidly and quickly spreads to other organs. It often responds to chemotherapy and radiation more impressively than does non-small cell cancer. There are two stages of small cell lung cancer:
- Limited stage- cancer is generally found only in one lung. There may also be cancer in nearby lymph nodes on the same side of the chest.
- Extensive stage – cancer has spread beyond the primary tumor in the chest to other parts of the body.
- Neuroendocrine tumors (formerly called carcinoid)
Mesothelioma is a rare form of chest cancer, largely caused by exposure to asbestos. The cancer usually forms in the mesothelial cells that line the lung and the chest wall. Despite current advanced technologies, mesothelioma is still a difficult-to-treat, aggressive cancer. Stanford researchers and physicians are actively involved in developing new and better treatments for this disease, and where appropriate can offer patients access to experimental therapies through clinical trials.
Symptoms of Lung Cancer
The following are the most common symptoms for lung cancer. However, each individual may experience symptoms differently.
Lung cancer usually does not cause symptoms when it first develops, but they often become present after the tumor begins growing. A cough is the most common symptom of lung cancer.
Other symptoms include:
- Constant chest pain
- Shortness of breath
- Recurring lung infections, such as pneumonia or bronchitis
- Bloody or rust colored sputum
- A tumor that presses on large blood vessels near the lung can cause swelling of the neck and face
- A tumor that presses on certain nerves near the lung causing pain and weakness in the shoulder, arm, or hand
- Fever for unknown reason
Like all cancers, lung cancer can cause:
- Loss of appetite
- Loss of weight
- Pain in other parts of the body not affected by the cancer
- Bone fractures
Other symptoms can be caused by substances made by lung cancer cells – referred to as a paraneoplastic syndrome. For example, certain lung cancer cells produce a substance that causes a sharp drop in the level of sodium in the blood, which can cause many symptoms, including confusion and sometimes even coma. Some tumors will cause swelling and pain along the shins in both legs, known as pulmonary hypertrophic osteoarthropathy.
None of these symptoms is a sure sign that you have lung cancer. Only a physician can tell whether your symptoms are caused by cancer or by another problem.
Consult your physician for a diagnosis.