Head-to-Head Comparison of 68 Ga-DOTATATE and 18 F-FDG PET in EBV-Positive Nonkeratinizing Nasopharyngeal Carcinoma.

Purpose: The aim of this study was to compare the clinical application value of 68 Ga-DOTATATE and 18 F-FDG PET/CT in Epstein-Barr virus (EBV)-positive nonkeratinizing nasopharyngeal carcinoma.

Patients And Methods: Patients underwent 18 F-FDG and 68 Ga-DOTATATE PET scans. The lesion numbers, tracer parameters, and primary tumor volume derived from contrast-enhanced MRI, 18 F-FDG, and 68 Ga-DOTATATE PET were compared. The correlation between clinical characteristics and PET parameters as well as the predictive value of PET parameters were analyzed.

Results: The median maximum standard uptake values (SUV max ) of 18 F-FDG and 68 Ga-DOTATATE in all 26 primary tumors was 15.00 and 9.73, respectively ( P = 0.001). 68 Ga-DOTATATE PET was superior to 18 F-FDG PET in detecting intracranial and skull base involvement. The primary tumor volume of 68 Ga-DOTATATE with 35% SUV max as the threshold had the highest consistency with that of contrast-enhanced MRI. 68 Ga-DOTATATE and 18 F-FDG PET/CT detected 103/108 (95.4%) and 101/108 (93.5%) regional lymph nodes metastases ( P = 0.552), and the median SUV max was 6.05 and 10.81, respectively ( P < 0.001). Furthermore, 68 Ga-DOTATATE PET/CT detected more distant metastases than 18 F-FDG (89/92 [96.7%] vs 54/92 [58.7%], respectively, P < 0.001). The plasma EBV DNA was positively correlated with the total metabolic tumor volume, lesion glycolysis, somatostatin receptor-expressing tumor volume, and lesion somatostatin receptor expression (all P values <0.05). The PET parameters in the non-objective response rate group were higher than those in the objective response rate group (all P values >0.05).

Conclusions: 68 Ga-DOTATATE PET/CT is a promising imaging modality for detecting primary and metastatic EBV-positive nonkeratinizing nasopharyngeal carcinoma and delineating primary tumor boundary.