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Types of Lung Cancer

Non-Small Cell Lung Cancer (NSCLC)

Non-Small Cell Lung Cancer (NSCLC) is the most common type of lung cancer, making up 80-85% of all cases. It typically grows and spreads more slowly than small cell lung cancer (SCLC). NSCLC is staged based on the size of the primary tumor and if and where the cancer has spread (stages I, II, III, IV). See Staging for more information.  Some lung cancer tumors are composed of cells from more than one type of NSCLC. 

There are different kinds of NSCLC but the most commonly diagnosed are:

Adenocarcinoma

  • Begins in the cells that form the lining of the lungs
  • Has gland-like properties
  • Makes up just over 30%of lung cancer diagnoses

Adenocarcinoma in situ (AIS)  (formerly bronchioloalveolar carcinoma or BAC)

  • Rare subset of adenocarcinoma that begins in the alveoli
  • Can spread without destroying other tissues
  • Makes up about 3% of lung cancer diagnoses

Minimally invasive adenocarcinoma (MIA) is a classification added in 2011 to describe certain, smaller adenocarcinoma lung tumors.    

Squamous cell carcinoma

  • Begins in the thin, flat cells that line the passages of the respiratory tract
  • Makes up just under 30% of lung cancer diagnoses

Large cell carcinoma

  • Poorly differentiated (has none of the features that would allow it to be diagnosed as another type of NSCLC)
  • Faster growing form of NSCLC
  • Makes up about 9% of lung cancer diagnoses

Large cell neuroendocrine tumors

  • Fastest growing type of NSCLC
  • Makes up about 2% of lung cancer diagnoses

What is a neuroendocrine tumor?

It is a tumor that forms in hormone-releasing cells. Hormones deliver messages to organs and neuroendocrine tumors create an overabundance of the hormones, which causes a variety of symptoms not seen in other cancers. More information on neuroendocrine tumors can be found at: Cancer.net.

Small Cell Lung Cancer (SCLC)

Small Cell Lung Cancer (SCLC) makes up 15-20% of all lung cancer cases. It is a type of neuroendocrine tumor with cells that are smaller in size than most other cancer cells. It is a fast-growing cancer that spreads rapidly to other parts of the body.  Some lung cancer tumors contain cells that are both SCLC and a form of NSCLC, often large cell.  SCLC is usually staged as either limited or extensive, depending on if, and where, the cancer has spread. See Staging for more information.   

Other types of tumors or cancers that can start in the lungs are:

Mesothelioma is a cancer of the lining of organs and not only can originate in the lungs but also the abdomen, heart, and chest. It is associated with exposure to asbestos. For more information on mesothelioma and its treatment, please visit the Mesothelioma Applied Research Foundation, www.curemeso.org.

Carcinoid tumors are a type of neuroendocrine tumor. There are two types: typical and atypical. They usually start in the neuroendocrine (hormone producing) cells that line organs such as the small intestine but also the lungs. For more information on carcinoid tumors, please visit the Carcinoid Cancer Foundation, www.carcinoid.org.