Relationship between primary lesion FDG uptake and clinical stage at PET–CT for non-small cell lung cancer patients: An observation

The aim of the present study was to investigate the relationship between FDG uptake and clinical stage for non-small cell lung cancer. The patients who were histologically or cytologically proven to be adenocarcinoma (AC) or squamous cell carcinoma (SCC) lung cancer and conducted FDG PET/CT staging were retrospectively reviewed. The FDG uptake was quantified as the maximum standardized uptake value (SUVmax). And the T-N-M status was determined mainly by FDG PET–CT imaging according to the 1997 update of the international staging system for lung cancer. From December 2003 to November 2007, 266 cases (194 men and 72 women; age range 31–90 years, median 62 years) were analyzed, which included 161 AC and 105 SCC patients. The present study showed that both size (3.23 ± 1.68 cm vs 2.63 ± 1.33 cm, P = 0.004) and SUVmax (9.82 ± 5.08 vs 8.43 ± 4.21, P = 0.016) were significantly greater for SCC compared to AC. There was positive correlation between the SUVmax and size for both SCC and AC (r = 0.651, 0.632, respectively; both P = 0.000). Significant difference is found among different stages in SUVmax for AC (F = 11.693, P = 0.000) but not for SCC (F = 1.514, P = 0.216). After controlling the size factor, a significant correlation was found between tumor stage and FDG uptake value for AC (r = 0.323, P = 0.000), but not for SCC (r = 0.113, P = 0.252). In conclusion, this observation showed that tumor size and histologic subtype had influences upon FDG uptake in non-small cell lung cancer. It demonstrated significant correlation between clinical stage and SUVmax for AC, but not for SCC.