Objective: Conventional prognostic factors are not yet sufficient to predict treatment outcomes factors in nasopharyngeal carcinoma (NPC). Parameters from PET/CT are still being investigated as a prognostic factor in nasopharyngeal cancer.
Materials and Methods: We retrospectively analyzed total lesion glycolysis (TLG), metabolic tumor volume (MTV), and maximum standardized uptake value (SUVmax) in patients with non-metastatic nasopharyngeal cancer treated with intensity-adjusted radiotherapy. According to the ROC analysis, we divided the whole cohort into two groups. Kaplan-Meier tests were used to evaluate survival differences between groups. Univariate and multivariate analyzes were performed to find the factors affecting the prognosis. P<0.05 was accepted as statistically significant.
Results: Ninety-one non-metastatic nasopharyngeal cancer patients were enrolled in this study. According to cut-off values, both MTVtumor and TLGnode were found as an independent prognostic factor for overall survival (OS). High MTVtumor (>21.5) and high TLGnode (>186.7) correlated with 4.9 and 4-fold increased mortality risk, respectively. Multivariate analyses showed high MTVtotal (>59.5) was associated with a 3.3 fold increased risk of locoregional recurrence. High TLGtotal (>181.56) was found to be independent prognostic factor for distant metastasis-free survival and it was associated with a 5.4 fold increased risk. The 5-years OS rate was 58.5% in high MTVtotal (>59.5) patients and 82.4% in low MTVtotal (<59.5) patients (p<0.01). The 5-years OS rates were 64.2% in patients with high TLGtotal (>181) and 88% in patients with low TLGtotal (p<0.01).
Conclusion: The results of our study showed that MTVtumor and TLGnode values are significant independent prognostic factors for OS.