Types of Lung Cancer and Prognosis
Types of Lung Cancer and Prognosis Lung cancers are generally classified into two types: small cell lung cancers (CSCC) and non-small cell lung cancers (NSCLC). This classification is based on the microscopic appearance of tumor cells. These two types of cancers develop, propagate, and are treated in different ways, so making a distinction between these two types is important.
CSCC comprises about 10-15% of lung cancers. This type of lung cancer is the most aggressive and fast growing of all types. CSCC is strongly related to smoking. SCLCs metastases quickly to many sites in the body and are most often discovered after they have spread abundantly.
NSCLC is the most common lung cancer, accounting for about 85% of all cases. The NSCLC has three main types identified by cell types found in the tumor. Them:
- Adenocarcinomas are the most common type of NSCLC in the United States and account for up to 40% of lung cancer cases. While adenocarcinomas are associated with smoking like other lung cancers, this type is also observed in non-smokers–especially women–who develop lung cancer. Most adenocarcinomas occur in the outer or peripheral areas of the lungs. They also tend to propagate to the lymph nodes and beyond. Adenocarcinoma in Situ (formerly known as Bronchoalveolar carcinoma) is a subtype of adenocarcinoma that develops frequently at several locations in the lungs and propagates along pre-existing alveolar walls. It may also look like pneumonia on chest X-rays. It increases in frequency and is more common in women. People with this type of lung cancer tend to have better prognosis than other types of lung cancer.
- Carcinomas of squamous cells were once more frequent than adenocarcinomas; Today, they account for about 25% to 30% of all cases of lung cancer. Also known as squamous carcinomas, squamous cell cancers most often occur in the central area of the chest in the bronchi. This type of lung cancer remains most often in the lung, spreads to the lymph nodes, and grows quite large, forming a cavity.
- Large cell carcinomas, sometimes called undifferentiated carcinomas, are the least common type of NSCLC, accounting for 10% to 15% of all lung cancers. This type of cancer has a strong tendency to spread to lymph nodes and remote sites.
Other types of cancer may occur in the lung; These types are much less common than NSCLC and CSCC and include only 5% to 10% of lung cancers:
- Bronchial carcinacés account for up to 5% of lung cancers. These tumors are generally small (3-4 cm or less) when diagnosed and occur most often in persons under 40 years of age. Unrelated to smoking, carcinoid tumors can metastasize, and a small proportion of these tumors secrete hormone-related substances. Carcinidés generally develop and propagate more slowly than bronchogéniques cancers, and many are detected early enough to be surgically removed.
- Supporting lung tissue cancers such as smooth muscle, blood vessels, or cells involved in the immune response are rare in the lung.
Types of Lung Cancer and Prognosis
As discussed previously, metastatic cancers of other primary tumors in the body are often found in the lung. Tumors from anywhere in the body can spread to the lungs either through the bloodstream, through the lymphatic system, or directly from nearby organs. Metastatic tumors are most often multiple, dispersed in the lung and concentrated in the outer areas rather than in the central areas of the organ.