Pathological validation of ¹⁸F-AlF-NOTA-octreotide PET/CT for neuroblastoma

Somatostatin receptor 2 (SSTR2) positron emission tomography/computed tomography (PET/CT) plays an important role in the diagnosis and treatment of neuroblastoma (NB), but it faces the issue of nonspecific uptake. Although the relationship between SSTR PET/CT and SSTR2 expression has been studied in neuroendocrine tumours (NETs), significant differences exist between NB and NETs, and the application of ¹⁸F-AlF-NOTA-octreotide (¹⁸F-OC) PET/CT in NB requires further investigation. This retrospective study assessed the relationship between ¹⁸F-OC PET/CT imaging parameters and immunohistochemical (IHC) scores for the quantification of SSTR2 expression in NB. We obtained imaging and clinical data from patients with initial or treated NB who underwent ¹⁸F-OC PET/CT at Shandong Cancer Hospital between June 2021 and March 2023. Pathologically validated and accurately localized lesions on PET/CT images were analysed. ¹⁸F-OC uptake was assessed using Krenning scores, maximum (SUV_max) and mean (SUV_mean) standardized uptake values. We determined SSTR2 expression by evaluating scores for human epidermal growth factor receptor 2 (HER2) score, immunoreactive score (IRS), histochemical score (H score), and Volante score. We analysed 71 lesions (NB, n = 51), NB that converted to ganglioneuroblastoma (GNB) after treatment (n = 9), and ganglioneuromas (GN, n = 11). SSTR2 scores and ¹⁸F-OC uptake were significantly higher in NB tumours than in GNB and GN tumours. Furthermore, 77.9% of ¹⁸F-OC PET/CT-positive lesions were SSTR2-positive by IHC, and imaging parameters were significantly positively correlated with HER2 score, IRS, and H score in the total cohort and the NB group (Rho range, 0.433-0.602; p < 0.000). No significant correlation was observed between imaging parameters and pathological scores in GNB and GN tumours (p > 0.05).There was high agreement between ¹⁸F-OC PET/CT imaging and SSTR2 IHC scores in newly diagnosed and residual NB tumours and no significant correlation between these two methods in GNB and GN tumours. These results indicate that PET/CT providing molecular evidence for future follow-up and guidance for NB treatment.