The lungs contain a number of specialized cell types that facilitate the transfer of oxygen from air in the lungs into the bloodstream, to allow oxygenation of tissues throughout the body. Lung cancer develops when any of the cells within the lung mutate, causing the cells to divide out of control and form tumors that can eventually turn life-threatening. There are a number of types of lung cancer that can all be deadly if left untreated.
Small Cell Lung Cancer
Small cell lung cancer accounts for around 12 percent of total lung cancer cases, according to the University of North Carolina. Small cell lung cancer is a group of cancers made up of three subtypes: small cell carcinoma, also called oat cell cancer; combined small cell carcinoma; and mixed small cell/large cell carcinoma. These three subtypes of cancer are named for how the tumor cells appear under a microscope.
In general, small cell lung cancers are very aggressive and are quickly able to spread to other organs. Definitive diagnosis of small cell lung cancer can be done via tissue biopsy, and after diagnosis the patient may be treated with surgery to remove the tumor, combined with radiotherapy or chemotherapy to kill remaining cancer cells. Small cell lung cancers can be deadly if not diagnosed in time.
Squamous Cell Carcinoma
Squamous cell carcinoma arises from epithelial cells within the lung, and accounts for 25 to 30 percent of lung cancer cases, according to the University of Maryland Medical Center. Epithelial cells are specialized cells that line body cavities, helping with organ function and protecting underlying tissue. In the lungs, squamous cells help make up the branching structures of the lung--they line the tubes within the lungs and prevent injury. Squamous cells carcinomas occur within the tubes of the lungs, leading to shortness of breath and difficulty breathing.
Smoking causes the vast majority of squamous cell carcinoma cases, according to the University of Maryland Medical Center. Once diagnosed, squamous cell carcinoma can be treated by chemotherapy, radiotherapy, surgery or targeted therapeutics. If left untreated, the cancer is often fatal.
Adenocarcinoma
Adenocarcinoma is a cancer that affects glandular tissue. Adenocarcinoma can affect glandular tissues throughout the body, but commonly leads to cancer in the lungs. The University of Maryland Medical Center reports that around 40 percent of lung cancers are adenomas. The lungs contain large amounts of glands which secrete mucous that protects the airways within the lungs, and mutation of the gland cells eventually gives rise to an adenocarcinoma.
Adenomas are typically asymptomatic until the cancer is relatively advanced and metastatic. The University of Maryland Medical Center states that adenocarcinoma readily metastasizes to the brain. Due to the advanced and aggressive nature of adenocarcinomas and the organs to which they readily metastasize, they are very deadly.
