Relationship between primary tumor fluorodeoxyglucose uptake and nodal or distant metastases at presentation in T1 stage non-small cell lung cancer

Many studies have shown that FDG uptake is related to prognosis of non-small cell lung cancer, and metastasis is the major cause of death due to lung cancer patients. However, the FDG uptake of primary tumor in relation to nodal or distant metastasis at presentation has not been studied directly. Newly diagnosed non-small cell lung cancer patients who accepted 18F-FDG PET/CT staging in the nuclear medicine center of Shandong Cancer Hospital between 1 June 2004 and 1 October 2007 were retrospectively reviewed. One hundred and seven patients with clinical T1 stage and definited histologic or cytologic evidence were enrolled and analyzed. Significant differences were observed in primary tumor SUVmax for different stages (Stage Ia–IV, P = 0.004), different N status (N0M0 vs. N1–3M0, P = 0.008) and tumors absence any spread vs. presence distant metastasis (N0M0 vs. M1, P = 0.000). Spearman rank analysis showed moderate correlations between SUVmax and different N or M status (r = 0.369, P = 0.000 for Stage Ia–IV; r = 0.337, P = 0.004 for N0M0 vs. N1–3M0; r = 0.474, P = 0.000 for N0M0 vs. M1; respectively). There was a statistically significant increase in the probability of metastases at presentation with each unit increase in SUVmax. (logistic regression model, OR = 1.469; 95% CI, 1.175–1.836; P = 0.001). These results suggest that FDG uptake is a potential indicator of metastases in small primary lesion of non-small cell lung cancer.