The most sensitive lung cancer to chemotherapy is small cell lung cancer. Small cell lung cancer is very sensitive to chemotherapy such as cisplatin plus etoposide regimen due to its fast growth and high malignancy, and the tumor will disappear rapidly or even go into complete remission after 1-2 cycles of chemotherapy. Small cell lung cancer is prone to recurrence or distant metastasis, so 2 cycles of chemotherapy is not enough and 6-8 cycles of chemotherapy are usually needed. Other lung cancers such as adenocarcinoma and squamous carcinoma are usually much less sensitive to chemotherapy than small cell carcinoma. Although the sensitivity of chemotherapy is not as high as that of small cell carcinoma, postoperative adjuvant chemotherapy or palliative chemotherapy is needed whenever the disease requires it, such as advanced non-small cell lung cancer and postoperative lymph node metastasis.