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Lung cancer

Lung cancer types

There are two main types of lung cancer: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC accounts for nearly nine out of every 10 diagnoses and typically grows at a slower rate than SCLC.

Small cell lung cancer

Small cell lung cancer is also known as “oat-cell” cancer because the cells look like oats under the microscope. It often starts in the bronchi, then quickly grows and spread to other parts of the body, including the lymph nodes. This type of lung cancer represents fewer than 20 percent of lung cancers and is typically caused by tobacco smoking.

Small cell lung cancer is divided into two types, named for the kinds of cells found in the cancer and how the cells look when viewed under a microscope:

  • Small cell carcinoma (oat-cell cancer)
  • Combined small cell carcinoma

Non-small cell lung cancer

Non-small cell lung cancer is the most common type of lung cancer. It accounts for nearly nine out of every 10 cases, and usually grows at a slower rate than SCLC. Most often, it develops slowly and causes few or no symptoms until it has advanced.

There are three main types of non-small cell lung cancer:

Adenocarcinoma of the lung: Lung adenocarcinoma is the most common form of lung cancer, accounting for 30 percent of all cases overall and about 40 percent of all non-small cell lung cancer occurrences. Adenocarcinomas are found in several common cancers, including breast, prostate and colorectal. Adenocarcinomas of the lung are found in the outer region of the lung, in glands that secrete mucus and help us breathe. Symptoms include coughing, hoarseness, weight loss and weakness.

Learn more about adenocarcinoma of the lung

Squamous cell: This type of lung cancer is found centrally in the lung, where the larger bronchi join the trachea to the lung, or in one of the main airway branches. Squamous cell lung cancer is responsible for about 30 percent of all non-small cell lung cancers, and is generally linked to smoking.

Large-cell undifferentiated carcinoma: Large-cell undifferentiated carcinoma lung cancer grows and spreads quickly and can be found anywhere in the lung. This type of lung cancer usually accounts for 10 to 15 percent of all cases of NSCLC. Large-cell undifferentiated carcinoma tends to grow and spread quickly.

Metastatic lung cancer

Because symptoms do not always develop when lung cancer is present, it is common for the cancer to metastasize before it is diagnosed. Even though the cancer may have formed a tumor in a new location in the body,

Learn more about metastatic lung cancer

Next topic: What is adenocarcinoma of the lung cancer?