Abstract：Objective To calculate the median survival time and survival rate of patients with early-stage non-small cell lung cancer (NSCLC), and analyze the survival difference of patients with different clinical characteristics after postoperative adjuvant chemotherapy, so as to provide a basis for doctors to screen patients with possible survival benefit of postoperative adjuvant chemotherapy.Methods The data of early-stage NSCLC patients undergoing surgical treatment were extracted from SEER database. Propensity score matching (PSM) was used to control confounding factors to obtain the postoperative adjuvant chemotherapy group and the control group. The main clinical characteristics were selected to test the interaction between these clinical characteristics and postoperative adjuvant chemotherapy. Kaplan-meier method was used to compare the median survival time, 3-year survival rate and 5-year survival rate of the adjuvant chemotherapy group and the control group with different clinical characteristics.Results There were 25 791 patients with early stage NSCLC who underwent surgical treatment. The propensity score model included 11 confounding factors, and 3 336 pairs of patient samples were obtained after matching, with good balance between groups. The interaction between postoperative adjuvant chemotherapy and TNM stage, N stage, histological type, differentiation degree, and age had statistical significance on the survival of patients(P<0.05). The clinical characteristics of patients with postoperative adjuvant chemotherapy survival benefit were: stage-II, stage-T2, stage-T3, stage-N1, poorly-differentiated tumor, histological type of squamous cell carcinoma, age＞60 years old. The median survival time of patients with survival benefit wassignificantly prolonged, and the 3-year and 5-year survival rates were higher than those of the control group(P<0.05). The patients with stage-II, stage-N1 and histological type squamous cell carcinoma had the most significant benefit: the HR of the postoperative adjuvant chemotherapy group with stage-II was 0.70(95%CI: 0.63-0.77); the HR of the postoperative adjuvant chemotherapy group with stage-N1 was 0.68(95%CI:0.59-0.77); the HR of the postoperative adjuvant chemotherapy group with squamous cell carcinoma was 0.68(95%CI:0.59-0.78). The 3-year and 5-year survival rates of stage-IA and well-differentiated patients in the chemotherapy group were lower than those in the control group. The HR of the postoperative adjuvant chemotherapy group with stage-IA was 2.33(95%CI:1.58-3.42); the HR of the postoperative adjuvant chemotherapy group with well-differentation was 1.76(95%CI:1.27-2.42).Conclusion Postoperative adjuvant chemotherapy can greatly improve the lung cancer-specific survival rate of patients with high TNM staging, poorly differentiation and pathological type of squamous cell carcinoma, so postoperative adjuvant chemotherapy is recommended; elderly patients should be careful to use postoperative adjuvant chemotherapy after strict evaluation of various indicators; postoperative adjuvant chemotherapy has adverse effects on the survival of stage-IA and well-differentiated patients. Doctors should be wary of overtreatment in clinical therapeutics.
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