Lung cancer is primarily categorized into two main types based on the appearance of cancer cells under a microscope and how they behave:
Non-Small Cell Lung Cancer (NSCLC): Non-small cell lung cancer accounts for about 85% of all lung cancer cases and includes several subtypes:
- Adenocarcinoma: Adenocarcinoma is the most common subtype of NSCLC, accounting for about 40% of cases. It usually develops in the outer parts of the lungs and is more common in non-smokers or former smokers.
- Squamous Cell Carcinoma (SqCC): Squamous cell carcinoma accounts for about 25-30% of NSCLC cases. It typically arises in the larger airways of the lungs and is strongly associated with smoking.
- Large Cell Carcinoma: Large cell carcinoma is a less common subtype of NSCLC, accounting for about 10-15% of cases. It can develop in any part of the lung and tends to grow and spread quickly.
Small Cell Lung Cancer (SCLC): Small cell lung cancer accounts for about 10-15% of all lung cancer cases. It is a highly aggressive type of lung cancer that tends to grow and spread rapidly. SCLC is strongly associated with smoking and is often diagnosed at an advanced stage. It typically originates in the bronchi, the large airways of the lungs, and has a high propensity for metastasis.
Apart from these main types, there are also rare types of lung cancer, such as carcinoid tumors and sarcomatoid carcinomas. Carcinoid tumors originate from neuroendocrine cells and tend to grow slowly. Sarcomatoid carcinomas are aggressive tumors that contain both epithelial and mesenchymal components.