ObjectiveTo compare the long-term prognosis of elderly patients with stageⅠnon-small cell lung cancer (NSCLC) after lobectomy or segmentectomy. MethodsData of elderly patients with stageⅠNSCLC were collected from the SEER database. According to the resection method, patients were divided into a lobectomy group and a segmentectomy group. The overall survival (OS) and lung cancer-specific survival (LCSS) of the two groups were compared by propensity score matching (lobectomy : segmentectomy=2:1). ResultsA total of 9990 patients were included, including 5840 (58.46%) females and 4150 (41.54%) males, with an average age of 70.48±6.47 years. Among them, 9029 patients were in the lobectomy group and 961 patients were in the segmentectomy group. After propensity score matching, a total of 2883 patients were matched, including 1922 patients in the lobectomy group and 961 patients in the segmentectomy group. There was no statistical difference in baseline data between the two groups (P>0.05). The 10-year OS rate and LCSS rate of the lobectomy group were higher than those of the segmentectomy group (OS: 51.15% vs. 38.35%, P<0.01; LCSS: 79.68% vs. 71.52%, P<0.01). Subgroup analysis found that the survival advantage of lobectomy was only limited to patients aged 60-70 years; for patients>70 years, there was no statistical difference in the 5-year and 10-year OS rates between the two surgical methods (P>0.05). In addition, for patients with tumor diameter ≤2 cm (stages ⅠA1-ⅠA2), lymph node dissection number≥10, and receiving adjuvant radiotherapy/chemotherapy, segmentectomy could also achieve a similar prognosis as lobectomy. ConclusionOverall, for elderly patients with stage ⅠNSCLC, lobectomy can achieve better OS and LCSS. However, individual differences, tumor characteristics, and perioperative treatment plans should be considered comprehensively to determine whether elderly patients with stageⅠNSCLC should undergo segmentectomy.