There are two main types of lung cancer: small cell and non-small cell. The two types differ in several ways, including how quickly they spread, how they are staged, and how they are treated. Knowing what type and stage of lung cancer you have can help you understand more about your treatment choices and prognosis.
Non-small cell lung cancer (NSCLC)
Non-small cell cancer is the most common type of lung cancer. It accounts for about 85 out of 100 lung cancer cases. Smoking is a major risk factor for non-small cell cancer, but it can have other causes.
In general, non-small cell cancer spreads more slowly than small-cell lung cancer.
Subtypes. The three major subtypes of non-small cell lung cancer are:
- Squamous cell carcinoma (also called epidermoid carcinoma)
- Large cell carcinoma
Less common types of non-small cell cancer include carcinoid tumors, salivary gland carcinoma, and unclassified carcinoma.
Staging. Doctors classify non-small cell lung cancer in stages using Roman numerals. The stages are based on factors that include how much the cancer has spread. The lower the number, the less advanced the cancer and, in general, the better the long-term outcome.
- Stage 0: Cancer cells are only in the lining of the lung. Also called carcinoma in situ.
- Stage I: Cancer is just in one area of the lung.
- Stage II: Cancer has spread to nearby lymph nodes or the chest wall.
- Stage III: Cancer has spread outside the lungs to nearby lymph nodes or other organs in the chest.
- Stage IV: Cancer has spread to other parts of the lung or other parts of the body, such as the brain, bones, or liver.
Doctors use a system of numbers and letters to classify non-small cell cancer into these stages. This is called the TNM system.
- T is for tumor size. This can range from T0 (no tumor) to T4 (large tumor).
- N is for lymph node involvement. This can range from N0 (no cancer in lymph nodes) to N3 (cancer in lymph nodes that are farther away from the tumor).
- M is for metastasis. M0 means the cancer has not spread to other parts of the body (distant metastasis). M1 means distant metastasis was found.
Treatment. Doctors use chemotherapy, surgery, radiation, and other treatments to treat non-small cell cancer. Often these treatments are combined to get the best results. Early-stage cancer can sometimes be cured with surgery, but cancer often comes back. By stage III, the cancer is usually too widespread for surgery, so chemotherapy is the standard treatment. If known treatments don't work, people with advanced cancer can take part in clinical trials to test new treatments.
Small cell lung cancer (SCLC)
Small cell cancer is much less common than non-small cell cancer. It accounts for only about 15 out of 100 lung cancer cases. It is almost always caused by smoking.
Small cell cancer is an aggressive cancer that grows and spreads quickly.
Subtypes. The three main subtypes of small cell cancer are:
- Oat cell
- Combined small cell/large cell carcinoma
- Intermediate cell
Staging. Because it spreads so rapidly, small cell lung cancer is usually grouped in only two stages:
- Limited, meaning the cancer is only in one lung and nearby tissue and lymph nodes.
- Extensive, meaning the cancer has spread to other parts of the chest or beyond the chest. Small cell cancer often spreads to the brain.
Treatment. Chemotherapy is always used to treat small cell cancer because it can travel throughout the body, attacking cancer cells wherever they have spread. Radiation may be used to treat limited stage cancer or cancer that has spread to the brain. Surgery is usually not an option for small cell cancer. This cancer is rarely found when it is small enough to be removed.
Created on 02/12/2008
Updated on 06/20/2011
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- Edelman MJ, Gandara DR. Lung cancer. In: Casciato DA, ed. Manual of Clinical Oncology. Philadelphia, PA: Lippincott Williams and Wilkins; 2009.
- National Cancer Institute. Small cell lung cancer treatment. Treatment option overview.
- American Society of Clinical Oncology. Lung cancer.