Follow-up is often recommended by clinicians for small pulmonary nodules. However, there is still no specific standard on how to follow up. Mimae et al. from the Department of Surgical Oncology, Hiroshima University, Japan, aim to establish imaging criteria for follow-up of small pulmonary nodules to accurately and extensively predict inert tumors, including adenocarcinoma in situ. The article was recently published in the journal Annals of Oncology. The study included 747 patients undergoing radical resection for clinical stage IA lung adenocarcinoma in a multicenter setting to analyze the correlation between preoperative factors and postoperative outcomes, as well as pathologic findings and prognosis. This study defined inert tumors as follows: tumors without invasion of lymphatic vessels, blood vessels, pleura, or lymph node metastases (LY0V0PL0N0). This study found that the pathological findings of 44/99 (44%) pure ground glass shadow tumors (pGGO) in surgical specimens included 3/15 (20%) pGGO ≤1 cm, which indicated that this fraction of pGGO had local invasion. Based on characteristic curves of postoperative data from patients with LY0V0PL0N0, a high-resolution CT (HRCT) shadow of ≤6 mm or an 18F FDG-PET/CT maximum standardized uptake value (SUVmax) of ≤0.6 in solid nodules can be used as imaging criteria to predict inert tumors. The results of this study confirmed that none of the 253/747 (34%) patients who met this criterion had recurrence during a mean follow-up of 38.6 months. The SUVmax of PET/CT and the size of the solid nodal shadow on HRCT predict inert LY0V0PL0N0 lung tumors, and clinicians may recommend follow-up for this group of patients.