Objective To investigate the risk fairs and significance of late recurrence in non-small cell lung cancer (NSCLC)patients who had undergone complete resection and remained recurrence-free for5 years.Methods 496 individuals diagnosed and surgically treated for Stage Ⅰ and Ⅱ A NSCLC were included.We examined patients at 3-month intervals for the first 2 years after surgery and typically at 6-month intervals thereafter on an outpatient basis.The follow-up evaluation included physical examination,inaging examination and tumor narkers.Pathological examination had also been performed when needed.Of these,336 patients remained recurrence-free for 5 years were followed up continuously for 3 years.Clinicopathologic factors were collected including age,sex,smoking history,preoperative serum carcinoembryonic antigen (CEA) level,surgical apprach,maximum tumor dimension on resected specimen,histologic type,histologic differentiation,intratumoral lymphatic permeation,intratumoral vascular invasion,pleural invasion and pathologic stage.The primary end event was lung cancer recurrence.The data collection ended in January 2011.Kaplan-Meier method was used for survival rate.Survival difference wasevaluated bylog-rank test.Multivariate Cox regression was used to test the relationship of recurrence-free probability to various clinicopathologic factors.Results At 5 years after resection,109 patients had died of disease and 33 had died of other causes.18 patients were alive with disease.The remaining 3 - 36 patients were alive and recurrence-free for the first 5 years.The median follow-up period of these 5-year recurrence free survivors was 27 months (range,3-36 months).34 (10.1％)patients developed a late recurrence at 3 years among the 336 patients.Recurrence was locoregional in 13 (38.2％)patients:6 patients in mediastinal lymph nodes,3 patients in ipsilateral lung,2 patients with pleural dissemination and 2 patients in other locations.Recurrence was distant in 21 (61.8％) patients:8 patients with multiple-organ metastases,13 patients with single-organ metastasis,and the latter consisted of 5 patients in contralateral lung,3 patients in liver,2 patients in central nervous system and 3 patients in other locations.Smoking history,preoperative serum CEA level,histologic differentiation,intratumoral lymphatic invasion,intratumoral vascular invasion,pleural invasion and pathologic stage were risk factors for late recurrence in univariate analysis.Multivariate Cox analysis demonstrated that intratumoral vascular invasion and intratumoral lymphatic invasion were independent risk factors for late recurrence.Conclusion NSCLC patients have a significant risk of late recurrence after complete resection 5 years,especially for the patients with intratumoral vascular invasion and intralumoral lymphatic invasion.It is needed and significant for the patients to follow up continuously after 5 years of complete resection.