Assessment of factors influencing FDG uptake in non-small cell lung cancer on PET/CT by investigating histological differences in expression of glucose transporters 1 and 3 and tumour size

Purpose The objective of this study was to evaluate the major factors influencing on FDG uptake in non-small cell lung cancer (NSCLC) by investigating histological difference in the expression of glucose transporters 1 and 3 (Glut-1 and Glut-3) and tumour size. Methods This study enrolled 32 patients including 9 with squamous cell carcinoma (SCC) and 23 with adenocarcinoma (AC). The AC cases comprised 16 AC with mixed subtypes (AC-mixed) and 7 localized AC in situ (localized bronchioloalveolar carcinoma). Partial volume effect corrected maximum standardized uptake values (cSUVmax) and tumour size were obtained using FDG PET/CT. Glut-1 and Glut-3 expression were evaluated using five-point grading scales. Results Overexpression of Gluts was observed at high rates (88% for Glut-1 and 97% for Glut-3). They were mutually correlated. cSUVmax showed better correlation with size than with Gluts overexpression. AC and SCC showed a high positive expression rate for both Glut-1 and Glut-3, although the degree of overexpression was significantly higher in SCC than AC. In addition, localized AC in situ revealed a considerably higher positive expression rate and similar degrees of overexpression for both Glut-1 and Glut-3 compared with AC-mixed. By contrast, localized AC in situ alone was significantly smaller in both cSUVmax and size than either SCC or AC-mixed. No significant difference was found in cSUVmax or size between SCC and AC-mixed. Conclusions The FDG uptake of NSCLC might be dependent on size rather than on overexpression of Glut-1 or Glut-3. Low FDG uptake in localized AC in situ might result from its small size rather than Glut overexpression.