Despite complete resection of what seems to be all evident tumor, one third to three quarters of patients with stages I and II NSCLC ultimately succumb to this neoplasm. Patients who are cured of an original NSCLC or small cell cancer remain at risk for a new primary lung cancer. Although the importance of lifelong surveillance is clear, the extent and timing of optimal follow-up remain undefined. Although clinicians refer to the development after treatment of clinically discernible sites of tumor as "recurrence," it is probably more accurate to consider these foci as "persistence"--that is, the locoregional site was not sterilized by surgery, and the distant implants were present from the outset but undetected. Although data are sparse, induction and improved adjuvant therapy for early NSCLC may be helpful. Much further experience is needed. Further study and application of biologic indicators in addition to TNM staging likely will help identify patients at high risk for surgical failure who may benefit by combination treatment.