The two major types of lung cancer are small cell lung cancer and non-small cell lung cancer. Lung cancer that carries characteristics of both is known as mixed small cell/large cell carcinoma.
SMALL CELL LUNG CANCER (SCLC)
Small cell lung cancer (SCLC), also known as oat cell carcinoma or small cell undifferentiated carcinoma, is the less frequent of the two major types, accounting for 20% of all lung cancer cases. Almost all cases of small cell lung cancer may be traced to smoking. It is rarely found in a person who has never smoked.
This is the type of cancer that is likely to spread to other parts of the body. The cancer cells are small, but are quick to multiply. They can form large tumors and affect other organs such as the lymph nodes, adrenal glands, bones, liver and brain. Because of this characteristic, systemic drug treatment is needed for possible distant metastasis.
NON-SMALL CELL LUNG CANCER (NSCLC)
Non-small cell lung cancer (NSCLC) is more common than SCLC, accounting for 80% of all lung cancer cases. It has three subtypes, with the cancer categorized depending on the size, shape and chemical make-up of the cancer cells. These subtypes are adenocarcinoma, squamous cell carcinoma, and large-cell undifferentiated carcinoma.
Adenocarcinoma
Adenocarcinoma, which is normally found in the peripheral areas of the lung, makes up ~40% of lung cancer cases. Patients with bronchioloalveolar carcinoma, a type of adenocarcinoma, appear to have a better outlook for survival than those afflicted with other types of lung cancer.
Squamous cell carcinoma (SCC)
SCC is often associated with smoking. It is usually found near a bronchus. It accounts for 25% and 30% of lung cancer cases.
Large-cell undifferentiated carcinoma
The third NSCLC sub-type, large-cell undifferentiated carcinoma, has a tendency to grow and spread rapidly throughout the body. Because of this feature, the prognosis for a patient with this type of cancer, which accounts for 5% to 10% of lung cancer cases, is usually poor.
OTHER TYPES OF LUNG CANCER
Other tumors can also occur in the lungs. The tumor can be benign, which means it is non-cancerous. Carcinoid tumors, which are small tumors somewhere between cancerous and benign, account for less than 5% of lung tumors. Typical carcinoid tumors are mostly slow-growing tumors that can be treated with surgery. When the tumor is somewhere between benign and small cell lung cancer, it is called an atypical carcinoid tumor. Malignant carcinoid tumors may spread to other parts of the body, but they usually offer a better prognosis compare to NSCLC or SCLC.
Other types of lung cancer include adenoid cystic carcinomas, sarcomas, lymphomas, and hamartomas are rare. These tumors are treated differently than the more common types of lung cancer.
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