Small cell lung cancer and non-small cell lung cancer originate from different tissue types and cannot be transformed into each other.
Small cell lung cancer originates from lung neuroendocrine cells, it is a kind of low differentiated malignant tumor with rapid proliferation and very high malignancy, it can develop extensive metastasis at early stage, and the prognosis is very poor, and the survival period of most of the patients is not more than 1 year.
Non-small cell lung cancer includes squamous carcinoma, adenocarcinoma, large cell carcinoma and so on, originated from different tissues.
Lung squamous carcinoma originates from bronchial squamous epithelial hyperplasia, adenocarcinoma originates from bronchial mucous gland epithelium, and histologic and immunologic characteristics of large cell lung cancer are different from those of small cell lung cancer. The principles of treatment for these types of lung cancer are generally the same.
Small cell lung cancer is classified separately because its biological behavior, treatment principles, and prognosis are very different from other types of lung cancer, and the other types of lung cancer are collectively referred to as non-small cell lung cancer. Small cell lung cancer and non-small cell lung cancer originate from different tissue cells and cannot undergo mutual transformation.