AIM: In the natural history of lung cancer with pure ground-glass nodule (GGN) or part solid GGN, not only the size but also the density of the tumour should be evaluated with computed tomography (CT). However, quantitative evaluation methods for tumour density are scarce. We hypothesised that the density could be quantitatively evaluated using the tumour CT values. MATERIALS AND METHODS: Patients undergoing surgery at our department between 2016 and 2021 and meeting the following conditions were considered eligible: two or more CT scans at least 6 months apart before surgery, primary lung adenocarcinoma, and pure or part solid GGN. Integration of CT values (ICV) of tumours at two time points was carried out using three-dimensional image analysis. ICV doubling time (IDT) calculated from changes in ICV was compared with volume doubling time (VDT). IDT and VDT were calculated based on the CT imaging interval. RESULTS: A total of 107 cases (54 men and 53 women
median age, 71) were analysed, consisting of 61 cases of pure GGN and 46 cases of part solid GGN. For all patients, IDT (median, 789 days) was significantly shorter than VDT (median, 1000 days) (p=0.026). IDT for part solid GGN (median, 588 days) was significantly shorter than that for pure GGN (median, 961 days) (p=0.005). CONCLUSIONS: The integration of CT values consistently reflected changes in both size and density of tumours containing ground-glass components. IDT could be a reliable indicator in the natural history of lung cancer with a ground-glass component.