Hematoxylin and eosin-stained slides of sections of the gross residual tumor were assessed in a total of 358 patients by pathologists blinded to the patient treatment and outcome. In this study, at least 1 section per cm of tumor greatest diameter was obtained. The number of slides examined for each case ranged from 5 to 30. Figure 1 shows the schematic diagram for histopathologic evaluation of NSCLC. The percentage of residual tumor was estimated by comparing the estimated cross-sectional area of the viable tumor foci with estimated cross-sectional areas of necrosis, fibrosis, and inflammation on each slide. Histologic parameters were analyzed including necrosis, fibrosis, foamy macrophages, giant cell reaction, cholesterol cleft granuloma, and inflammation. The results for all slides were averaged together to determine the mean values for each patient. All histopathologic changes were then compared with patients who had not received neoadjuvant chemotherapy.