Role of PET/CT in Differentiating Synchronous Second Primary Lung Masses from Lung Metastases

FDG uptake of pulmonary lesions in synchronous primary lung cancers and lung metastases

“…The study demonstrated a statistically significant difference in SUV max ratio (2.6 ± 1.7 vs. 1.7 ± 0.6, p < 0.001) and relative ∆SUV max (0.50±0.23 vs. 0.34±0.17, p = 0.001) between the synchronous primary cancer and metastasis groups, which agrees with and builds upon findings reported in previous retrospective studies [ [14] , [15] , [20] , [21] ]. Dijkman et al [ 14 ] studied 37 patients with metastases (n=21) and second primary lung cancer (n=16) and found that ∆SUV max was significantly higher in patients with second primary cancer than in those with metastatic disease (58% vs. 28 %, respectively, p < 0.001).…”

“…Another study [ 22 ] found that synchronous primary tumours were more likely than metastatic spread if SUV max differences between two lesions fell outside of the range of 50 % to 200 %. Relative ∆SUV max has also been studied where tumours with the same clonal origin (i.e., metastases) demonstrate similar FDG uptake [ [14] , [20] , [21] ]. Optimal cut-off values of 41 % [ 14 ] and 35 % [ 21 ] for relative ∆SUV max have been reported, with one study correctly predicting almost 75 % of all histopathologically-confirmed synchronous multiple primary cancers using the former recommendation [ 20 ].…”

“…Relative ∆SUV max has also been studied where tumours with the same clonal origin (i.e., metastases) demonstrate similar FDG uptake [ [14] , [20] , [21] ]. Optimal cut-off values of 41 % [ 14 ] and 35 % [ 21 ] for relative ∆SUV max have been reported, with one study correctly predicting almost 75 % of all histopathologically-confirmed synchronous multiple primary cancers using the former recommendation [ 20 ]. Nonetheless, these studies included comparisons involving extrapulmonary tumours in their analysis, whereas the current study examined SUV max relationships among lung malignancies only.…”