Utility Of F-18-Alf-Nota-Octreotide Pet/Ct In The Localization Of Tumor-Induced Osteomalacia

Context: Tumor-induced osteomalacia (TIO) is a paraneoplastic disorder, usually caused by benign mesenchymal tumors that produce high levels of fibroblast growth factor 23. The only curative therapy is resection of the causative tumors.Objective: This research was conducted to evaluate the efficacy of F-18-AlF-NOTA-octreotide (F-18-OC) positron emission tomography/computed tomography (PET/CT) in detecting TIO and its impact on patient management.Methods: Retrospective analysis was conducted of 17 patients with hypophosphatemic osteomalacia suspected to be TIO. A F-18-OC PET/CT study was performed in all 17 patients to localize the tumor and Ga-68-DOTATATE PET/CT was performed in 4 out of 17 patients; both studies were performed within 1 week of each other. Both studies were interpreted blindly without the knowledge of other imaging findings. The image findings were compared with the results of histopathological examinations and clinical follow-ups.Results: The F-18-OC PET/CT scans were positive in 14 patients. Furthermore, 4 of 14 patients were scanned with both F-18-OC and Ga-68-DOTATATE PET/CT. Both studies were able to localize the tumor in all 4 patients. In total, 14 patients had surgery to remove the lesions. Postsurgical pathological examination confirmed causative tumors in these patients, whose symptoms diminished promptly. Serum phosphate levels normalized, confirming the diagnosis of TIO. F-18-OC PET/CT sensitivity, specificity, and accuracy were 87.5%, 100%, and 88.2% respectively. F-18-OC PET/CT findings affected patient management in 88.2% of cases.Conclusion: F-18-OC PET/CT scan is useful in the detection of tumors causing TIO. Further studies with larger patient populations are needed to validate the result.