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 = 0.002 and p = 0.016, respectively). NTR values were significantly higher in patients with distant metastases (p = 0.047). 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 = 0.047). Multivariate analysis showed that LN SUVmax, LN SUVmean and NTR were associated with DMFS (P = 0.003, 0.05 and 0.014, respectively), while primary tumor TLG and MTV values were associated with LRRFS (P = 0.035 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.