68 Ga DOTANOC PET/CT Scan in Primary Juvenile Nasopharyngeal Angiofibroma - A Pilot Study.

OBJECTIVES/HYPOTHESIS: Somatostatin receptors (SSTRs) are highly expressed in neuroendocrine tumors and is exploited for its imaging and treatment. SSTRs expression is also demonstrated in diverse benign and malignant tumor cell types and proliferating peri-tumoral vessels. Similarly, Juvenile Nasopharyngeal Angiofibroma (JNA) expresses different SSTRs and may be utilized for its imaging and treatment using DOTA, 1-Nal3-octreotide (DOTANOC)-PET/CT scan.

STUDY DESIGN: Prospective cohort.

METHODS: Nineteen clinico-radiologically diagnosed primary JNA patients underwent a 68 Ga-DOTANOC PET-CT scan. Using a dedicated PET/CT scanner, a low-dose head and neck spot CT scan was performed after 45 to 60 minutes of intravenous injection of 2 to 3 mCi(74-111 MBq) of DOTANOC. The primary objective was to assess the intensity and pattern of DOTANOC uptake in these patients.

RESULTS: DOTANOC expression was noted in all cases (n = 19) of primary JNA (100%). The mean (SD) DOTANOC SUVmax ratio of tumor and background was 6.9+/-1.4(range, 3.8-9.5). Intra-cranial extension in all 13/19 patients was prominently visualized due to the absence of DOTANOC uptake in the brain. Compared to the background all stages of JNA showed significant DOTANOC uptake (P < .0001). No difference in uptake between advanced-stage tumors and early tumors was noted (P = .47). A statistically non-significant negative trend was noted for decreasing uptake with increasing age (Spearman correlation coefficient, r = -0.19).

CONCLUSIONS: This first study of 68 Ga-DOTANOC-PET/CT scan in JNA demonstrates consistent and reliable uptake activity in all patients irrespective of age and stage. This opens up possibilities to physiological diagnostic imaging with a promise of greater specificity and sensitivity and may have applications in ambivalent diagnostic situations such as the detection of recurrence.

LEVEL OF EVIDENCE: 3 Laryngoscope, 131:1509-1515, 2021.