Types of Lung Cancer
Lung cancer is a complex disease that emcompases many different types. Because of this, it’s important to understand each as they affect both your treatment options and your prognosis.
Lung cancers are broadly classified into two types — small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC) — which are then broken down into a specific subtype. Both small cell lung cancer and non-small cell lung cancer are named for the types of cells found in the cancer and how the cells appear when viewed under a microscope. The cancer cells of each type grow and spread in different ways.
Small Cell Lung Cancer
Small cell lung cancer (SCLC) accounts for about 10% to 15% of all lung cancers. Although considered a fast-growing cancer, SCLC responds favorably to treatments, including chemotherapy and radiation. Immunotherapy, laser therapy, or surgery are other treatment methods that may be used.
The two general types include:
- Small cell carcinoma (also known as oat cell cancer)
- Combined small cell carcinoma
A chest x-ray is often the first diagnostic test your doctor may run to look for any abnormal areas in the lungs. If something suspicious is seen, your doctor may order more tests like the following:
- CT scan
- Bone scan
- PET scan
Smoking tobacco is a major risk factor for developing small cell lung cancer.
Non-Small Cell Lung Cancer
NSCLC is the most common type of lung cancer in the United States, accounting for about 80% to 85% of lung cancers. There are several types of non-small cell lung cancer:
- Squamous cell carcinoma: Cancer that forms in the thin, flat cells lining the inside of the lungs. This is also called epidermoid carcinoma. Squamous cell lung tumors usually occur in the central part of the lung or in one of the main airways (left or right bronchus).
- Large cell carcinoma: Cancer that may begin in several types of large cells. These lung cancers do not always occur near the chest wall. They do often occur near the edge of the lung rather than near a bronchus (in the center).
- Adenocarcinoma: Cancer that begins in the cells that line the alveoli and make substances such as mucus. This type is usually located more along the outer edges of the lungs and tends to grow more slowly than other lung cancers.
Other less common types of non-small cell lung cancer include pleomorphic, carcinoid tumor, salivary gland carcinoma, and unclassified carcinoma.
Smoking is the major risk factor for non-small cell lung cancer.
The following diagnostic tests might be used to identify NSCLC:
- Bone scan
- Pulmonary function test
- PET scan
- CT scan
- Bone marrow aspiration and biopsy
NSCLC may be treated with:
- Targeted therapy
- Laser therapy
Other Types of Lung Tumors
Even though lung cancers typically fall within the above categories, there are exceptions. Other types of tumors can occur in the lungs, including:
- Adenosquamous carcinoma: A hybrid of adenocarcinoma and squamous cell lung cancer.
- Salivary gland cancer: A rare cancer that forms in tissues of a salivary gland (gland in the mouth that makes saliva). Most salivary gland cancers occur in older people.
- Large cell neuroendocrine carcinoma: An aggressive subtype of non-small cell lung cancer.
- Mesothelioma: forms in thin tissue called mesothelium (lines along with the lungs and the abdomen). This type of lung cancer is linked to asbestos exposure.
- Lung carcinoids tumors. These tumors start in neuroendocrine cells, which are a special kind of cell found in the lungs. This type of cancer can be found in younger than average lung cancer patients.
- Cancers that spread to the lungs. Sometimes, cancer that starts in another organ can metastasize to the lungs. Cancers such as these are not considered lung cancer but rather a cancer of the organ in which it originated and would be treated as such.