Head-to-Head Comparison of (68)Ga-DOTA-TATE and (68)Ga-DOTA-JR11 PET/CT in Patients With Tumor-Induced Osteomalacia: A Prospective Study

BACKGROUND: The purpose of this study is to compare the sensitivity of (68)Ga-DOTA-JR11 and (68)Ga-DOTA-TATE PET/CT for detecting the responsible tumor of tumor-induced osteomalacia (TIO) and investigate if (68)Ga-DOTA-JR11 PET/CT can identify the culprit tumor of TIO in multiple suspicious lesions in (68)Ga-DOTA-TATE PET/CT. METHODS: A total of 19 patients with suspected TIO were prospectively recruited in this study. Each patient underwent whole-body PET/CT scan 40–60 min postinjection using (68)Ga-DOTA-TATE and (68)Ga-DOTA-JR11 on the same PET/CT, respectively in sequence, and on consecutive days. The diagnosis of TIO was confirmed by the combination of the postsurgical pathological results of the tumor and clinical information. RESULTS: Among the 19 patients with TIO who were included in this study, culprit tumors from all patients were confirmed pathologically. (68)Ga-DOTA-TATE PET/CT positively identified the causative tumor in 18/19 patients, whereas (68)Ga-DOTA-JR11 PET/CT was positive in 11/19 patients (94.7% vs. 57.9%, respectively; p < 0.05). (68)Ga-DOTA-TATE PET/CT demonstrated more than one increased focal activity in 7 patients for a total of 16 lesions (3 lesions each in 2 patients and 2 lesions each in the rest 5 patients). However, seven of these 16 lesions showed concordant results on (68)Ga-DOTA-JR11 PET/CT by demonstrating increased activity (one lesion in each of the 7 patients). The surgical specimens of the lesions in these 7 patients confirmed the phosphaturic mesenchymal tumor. A total of 11 culprit tumors were positive in both (68)Ga-DOTA-TATE and (68)Ga-DOTA-JR11 PET/CT. The SUVmax of 11 culprit tumors was significantly higher on (68)Ga-DOTA-TATE PET/CT compared with that on (68)Ga-DOTA-JR11 PET/CT (17.8 ± 12.5 vs. 6.8 ± 6.2; p < 0.05). CONCLUSIONS: (68)Ga-DOTA-TATE PET/CT is more sensitive to (68)Ga-DOTA-JR11 PET/CT in the detection of the culprit tumor of TIO. However, (68)Ga-DOTA-JR11 PET/CT might be helpful to identify the tumor in multiple suspicious lesions in (68)Ga-DOTA-TATE PET/CT. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov, identifier NCT 04689893.