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+/-1.68cm vs 2.63+/-1.33cm, 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.