ERSA is an anti-cancer drug used to treat lung cancer. It is a targeted therapy drug that can effectively control the growth of cancer and stabilize the disease. According to clinical statistics, more than half of the patients are able to stop the growth of lung cancer tumors, and the treatment success rate is relatively high, that is, it can reach 50%. In general, in clinical studies, the survival period of lung cancer patients treated with oral ERSA can reach more than seven years. In addition, the side effects of the drug are relatively small and can be tolerated by patients after taking it, which can well control the growth of tumor and thus prolong the life cycle of patients.