Lung cancer - non-small cell; NSCLC
Although lung cancer accounts for only 15% of all newly-diagnosed cancers in the United States, it is the leading cause of cancer death in U.S. men and women. It is more deadly than colon, breast, and prostate cancers combined. An estimated 159,000 people will die from lung cancer in 2009. Death rates have been declining in men over the past decade, and they have about stabilized in women.
The lungs are two spongy organs surrounded by a thin moist membrane called the pleura. Each lung is composed of smooth, shiny lobes: the right lung has three lobes, and the left has two. About 90% of the lung is filled with air. Only 10% is solid tissue.
Lung cancer develops when genetic mutations (changes) occur in a normal cell within the lung. As a result, the cell becomes abnormal in shape and behavior, and reproduces endlessly. The abnormal cells form a tumor that, if not surgically removed, invades neighboring blood vessels and lymph nodes and spreads to nearby sites. Eventually, the cancer can spread (metastasize) to locations throughout the body.
The two major categories of lung cancer are small cell lung cancer and non-small cell lung cancer. Most lung cancers are non-small cell cancer, the subject of this report. Less common cancers of the lung are known as carcinoids, cylindromas, and certain sarcomas (cancer in soft tissues). Some experts believe all primary lung cancers come from a single common cancerous (malignant) stem cell. As it copies itself, that stem cell can develop into any one of these cancer types in different people.
In addition, cancers in the lung may have spread from other sites, such as the breast, thyroid, or colon. In these cases, doctors name the cancer after its original location, such as "breast cancer with lung metastases."
Non-small cell lung cancers are categorized into three types:
These separate types are grouped together because, in the early stages before the cancers have spread, they all can be treated with surgery.
Squamous Cell Carcinoma. Squamous cells are formed from reserve cells. These are round cells that replace injured or damaged cells in the lining (the epithelium) of the bronchi, the major airways. Tumors formed from squamous cells are usually found in the center of the lung, either in a major lobe or in one of the main airway branches. They may grow to large sizes and form cavities in the lungs.
When squamous cell cancer spreads, it may travel to the bone, adrenal glands, liver, small intestine, and brain.
Squamous cell carcinoma is nearly always caused by smoking, and it used to be the most common cancer. It still makes up 25 - 30% of all lung cancers.
Adenocarcinoma. Adenocarcinomas usually start from the mucus-producing cells in the lung. About two-thirds of adenocarcinomas develop in the outer regions of the lung, while one-third develop in the center of the lung.
In 1965, 12% of lung cancers were adenocarcinomas. They are now estimated to account for 40% of all lung cancers and are the most common lung cancers in many countries. They are also the most common lung cancers in women, and their rates are increasing dramatically in men. Until recently, adenocarcinoma was only weakly linked to smoking. Experts now suggest, however, that the dramatic increase in this lung cancer type in recent decades may be due to low-tar, filtered cigarettes. People who smoke them draw tiny particles deeper into their lungs.
The course of this cancer varies widely. Most often, it develops slowly and causes few or no symptoms until it is far advanced. In some cases, however, it can be extremely aggressive and rapidly fatal. In 50% of cases in which this cancer spreads, it spreads only to the brain. It also can spread to the other lung, liver, adrenal glands, and bone.
Bronchoalveolar Lung Cancer. Bronchoalveolar lung cancer is actually a subtype of adenocarcinoma. It develops as a layer of column-like cells on the lung and spreads through the airways, causing great volumes of sputum. This cancer also is increasing in incidence.
Large Cell Carcinoma. Large cell carcinoma, which makes up about 10 - 15% of lung cancers, includes cancers that cannot be identified under the microscope as squamous cell cancers or adenocarcinomas.
Small cell lung cancer may, like squamous cells, originate from reserve cells or other cells in the epithelium. It causes 10 - 15% of all lung cancers. Without chemotherapy, it is very aggressive and usually rapidly fatal. It requires a different treatment approach from non-small cell lung cancer, so it is not discussed in this report.
Alberg AJ, Ford JG, Samet JM; American College of Chest Physicians. Epidemiology of lung cancer: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:29S-55S.
Aldington S, Harwood M, Cox B, Weatherall M, Beckert L, Hansell A, et al. Cannabis use and risk of lung cancer: a case-control study. Eur Respir J. 2008;31:280-286.
Bach PB, Silvestri GA, Hanger M, Jett JR. Screening for lung cancer: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:69S-77S.
Fischer B, Lassen U, Mortensen J, et al. Preoperative staging of lung cancer with combined PET-CT. N Engl J Med. 2009;361(1):32-39.
Gill A. Bong lung: regular smokers of cannabis show relatively distinctive histologic changes that predispose to pneumothorax. Am J Surg Pathol. 2005;29(7):980-982.
Jett JR, Schild SE, Keith RL, Kesler KA. Treatment of non-small cell lung cancer, stage IIIB: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:266S-276S.
Johnson DH, Blot WJ, Carbone DP, et al. Cancer of the lung: Non-small cell lung cancer and small cell lung cancer. In: Abeloff MD, Armitage JO, Niederhuber JE, Kastan MB, McKena WG. Clinical Oncology. 4th ed. Philadelphia, Pa: Churchill Livingstone Elsevier; 2008:chap 76.
Lencioni R, Crocetti L, Cioni R, Suh R, Glenn D, Regge D, et al. Response to radiofrequency ablation of pulmonary tumours: a prospective, intention-to-treat, multicentre clinical trial (the RAPTURE study). Lancet Oncol. 2008;9:621-628.
Lilly Inc. Alimta Prescribing Information. Rev. 10/2008.
Mehra R, Moore BA, Crothers K, Tetrault J, Fiellin DA. The association between marijuana smoking and lung cancer: a systematic review. Arch Intern Med. 2006 Jul 10;166(13):1359-67.
Molina JR, Yang P, Cassivi SD, Schild SE, Adjei AA. Non-small cell lung cancer: epidemiology, risk factors, treatment, and survivorship. Mayo Clin Proc. 2008; 83(5):584-594.
National Cancer Institute. Lung Cancer Home Page. Bethesda, Md.: U.S. National Institutes of Health. Accessed August 3, 2008.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Non-Small Cell Lung Cancer. Version 2.2008. Accessed July 3, 2009.
Rivera MP, Mehta AC. Initial diagnosis of lung cancer: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:131S-148S.
Robinson LA, Ruckdeschel J, Wagner H, Stevens CW. Treatment of non-small cell lung cancer-stage IIIA: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:243S-265S.
Sarafian T, Montes C, Harui A, et al. Clarifying CB2 receptor-dependent and independent effects of THC on human lung epithelial cells. Toxicol Appl Pharmacol. 2008;231(3):282-290.
Scott WJ, Howington J, Feigenberg S, Movsas B, Pisters K. Treatment of non-small cell lung cancer stage I and stage II: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:234S-242S.
Shen KR, Meyers BF, Larner JM, Jones DR. Special treatment issues in lung cancer: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:290S-305S.
Silvestri GA, Gould MK, Margolis ML, Tanoue LT, McCrory D, Toloza E, Detterbeck F. Noninvasive staging of non-small cell lung cancer: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007;132:178S-201S.
Slatore CG, Littman AJ, Au DH, Satia JA, White E. Long-term use of supplemental vitamins, vitamin C, Vitamin E, and folate does not reduce the risk of lung cancer. Am J Respir Crit Care Med. 2008;177:524-530.
Tassinari D, Scarpi E, Sartori S, et al. Second-line treatments in non-small cell lung cancer. A systematic review of literature and metaanalysis of randomized clinical trials. Chest. 2009;135(6):1596-1609.
Ung YC, Maziak DE, Vanderveen JA, Smith CA, Gulenchyn K, Evans WK, et al. 18-fluorodeoxyglucose positron emission tomography in the diagnosis and staging of lung cancer: a clinical practice guideline. Cancer Care Ontario. 2007 (Evidence-based series; no.7-20).
U.S. Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta, Georgia: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2006.
Yang P, Sun Z, Krowka MJ, Aubry MC, Bamlet WR, Wampfler JA, et al. Alpha1-antitrypsin deficiency carriers, tobacco smoke, chronic obstructive pulmonary disease, and lung cancer risk. Arch Intern Med. 2008;168:1097-1103.
© 2011 University of Maryland Medical Center (UMMC). All rights reserved.
UMMC is a member of the University of Maryland Medical System,
22 S. Greene Street, Baltimore, MD 21201. TDD: 1-800-735-2258 or 1.866.408.6885