Lung cancers
are classified into two types: small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC). The three most common types of lung cancer are represented in NSCLC: adenocarcinoma, squamous cell carcinoma and large cell carcinoma. According to the American Cancer Society, these three types comprise approximately 85% of lung cancers.
Adenocarcinoma
Adenocarcinoma is the most common of the three types, comprising almost half of all cases of NSCLC. Adenocarcinoma normally develops in the outer area of the lungs, and is found mostly in smokers, though it can occasionally be found in non-smokers. This form of cancer is characterized by growth of abnormal cells, which can spread to other parts of the body. Adenocarcinoma is more likely than other types of lung cancer to be contained in one area of the body, which is helpful in treatment, where surgery can remove the tumor if it is present in one area.
Squamous Cell Carcinomas
Squamous cell carcinomas, also known as epidermoid carcinomas, comprise nearly a third of NSCLC. These tumors develop most frequently in the central chest area in the bronchi and can cause symptoms of coughing up blood at an earlier stages than tumors located on the edges of the lungs, such as adenocarcinoma. Squamous cell carcinoma has been decreasing in prevalence, likely due to people inhaling smoke more deeply into the lung after the advent of filtered cigarettes.
Large Cell Carcinomas
Large cell carcinomas are the least common type of NSCLC, and are sometimes referred to as undifferentiated carcinomas. Large cell carcinomas are characterized by the size of the anaplastic cells and the uncontrolled growth of abnormal cells in the lungs. Found in the central portion of the lung, the tumors are often accompanied by extensive bleeding and tissue damage. Large cell carcinomas tend to grow quickly and spread at an earlier stage than other forms of NSCLC.
Others
There are several other, less common types of NSCLC, including pleomorphic, carcinoid tumor, salivary gland carcinoma and unclassified carcinoma. It should also be noted that the three main types of NSCLC may be present in some mixture in a patient with lung cancer.
SCLC and Bronchial Carcinoids
Accounting for the remaining 10% of lung cancers (mixtures and abnormal lung cancers account for the missing 5%) are SCLC and bronchial carcinoids. SCLC are the most aggressive and rapid-developing type of lung cancers. With only 1% in non-smokers, SCLC are strongly linked to cigarette smoking. Bronchial carcinoids are unrelated to cigarette smoking. This type of lung cancer grows slowly and can be detected early enough for surgical treatment.
Tags: lung cancer, lung cancers, cell carcinoma, Large cell, abnormal cells
