Staging in nasopharynx cancers prognostic value of volumetric parameters in [18F]FDG PET/CT imaging

Objective The aim of our study was to determine whether volumetric parameters measured from the primary lesion and metastatic lymph node (LN) using [18F]FDG PET/CT imaging affect prognosis and survival in nasopharyngeal cancer (NPC) patients. Material and methods Our study included 62 patients diagnosed with NPC who underwent [18F]FDG PET/CT imaging for pre-treatment staging. SUVmax, SUVmean, MTV and TLG values were measured from the primary tumor and LN. Lymph node/primary tumor SUV ratio (NTR) was calculated. The relationships between volumetric parameters and overall survival (OS), locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS) and progression-free survival (PFS) were evaluated. Results LN SUVmax and LN SUVmean values were significantly higher in patients with distant metastases ( P =.002 and P =.016, respectively). NTR values were significantly higher in patients with distant metastases ( P =.047). The ideal LN SUVmax and SUVmean cut-off values for predicting distant metastasis in patients with LN metastasis were 16.45 and 6.5, respectively. There was a statistically significant difference between the DMFSs of the two groups when the NTR cut-off value was 0.8 ( P =.047). Multivariate analysis showed that LN SUVmax, LN SUVmean and NTR were associated with DMFS ( P =.003, 0.05 and 0.014, respectively), while primary tumor TLG and MTV values were associated with LRRFS ( P =.035 and 0.03, respectively). Conclusion In conclusion, we believe that LN SUVmax, SUVmean and NTR may be prognostic indicators for distant metastasis, and MTV and TLG for locoregional recurrence.