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

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 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.

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).

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.