Clinical Study of Combined Radical Operation With Postoperative Adjuvant Chemotherapy and Prophylactic Cranial Irradiation in pT1-2N0M0 Stage of Small Cell Lung Cancer

At present, for participants with cT1-2N0 small cell lung cancer (SCLC), the International guidelines recommend surgical radical resection (lobectomy + systematic lymph node sampling or cleaning); If the postoperatively pathological examination is confirmed to be in pT1-2N0 stage, a single postoperative adjuvant chemotherapy (combining etoposide with cisplatin) is recommended. If participants are difficult to tolerate the side effects of cisplatin, the investigators can replace cisplatin by carboplatin in the adjuvant chemotherapy scheme. Participants with pT1-2N0 SCLC are not recommended to receive postoperative chest-assisted radiotherapy. For participants with pT1-N0 SCLC after specific surgical resection, prophylactic cranial irradiation (PCI) is currently recommended. But this recommendation is currently lacking the support of research evidence. The main purpose of this study is to study the prognostic effects of PCI on participants with pT1-2N0 stage small cell lung cancer (SCLC) who have received radical surgery and postoperative adjuvant chemotherapy. The main endpoint of this study is to observe the total survival rate (5-year OS%) in 5 years. The secondary outcome measures include 5 years of disease-free survival (5-year DFS%), disease-free survival (DFS), overall survival (OS), surgical complications, resection rates, quality of life (QoL), and exploration of biomarkers (tumor tissue). This is a two-arm, open, multicentral clinical study designed to compare the 5-year OS% of participants receiving or not receiving PCI for pT1-2N0 stage small cell lung cancer (SCLC) with radical surgery plus postoperative adjuvant chemotherapy. Previous literature reports that the 5-year OS% of participants with pT1-2N0 period SCLC who have received surgical resection is about 50%. Assuming that PCI can increase 5 years OS% by 10%, then enrolling 320 participants in the group can guarantee 70% degree of certainty with observing a unilateral significant difference α\< 0.1. Taking about 10% of the follow-up loss rate into account, the investigators expect to enroll 360 participants. Dividing the 360 participants divided into two groups randomly, each group is composed of 180 people. All participants received lobectomy plus mediastinal lymph node dissection or systematic lymph node sampling. Participants in the control group are enrolled in the follow-up, and the participants in research group will receive PCI by 25gy/10fx.