Theranostics in pheochromocytomas / paragangliomas: pilot study in chinese population

Pheochromocytomas and paragangliomas (PHEOs/PGLs) are rare tumors arising from chromaffin tissues in adrenal medulla and in extra-adrenal sites including sympathetic and parasympathetic paraganglia, respectively. The aim of this study was to evaluate SSTR based theranostics in PHEOs/PLs, and compared with 131I-MIBG. Thirty-eight consecutive patients with suspected or known PHEOs/ PGLs were consecutively enrolled in this study. All patients underwent ⁶⁸Ga-DOTA-NOC PET/CT, whereas twenty patients also underwent 131I-MIBG SPECT/CT in a month. Per-patient and per-lesion analysis was performed, final diagnosis was confirmed by histopathology and follow-up. ⁶⁸Ga-SSA positive patients were recruited to 177Lu-DOTA-TATE therapy, whereas 131I-MIBG positive patients underwent MIBG therapy. Adverse events were evaluated, tumor response was evaluated by quality of life, serum CGA level, catecholamine and metabolites changes, clinical symptoms and signs release including hypertension improvement, all patients have been followed-up for 1 year. For patient-based analysis, 31 patients were positive while 7 patients were negative on ⁶⁸Ga- DOTA-NOC PET/CT. The overall sensitivity, specificity and accuracy of ⁶⁸Ga-DOTA-NOC were 87.9%, 60% and 84.2%, respectively. On a lesion-based analysis, there are totally 218 lesions confirmed by histopathology or imaging follow-up, including 64 bone metastasis and 46 lymphadenopathy. 190 lesions were interpreted as positive while 28 were negative. The overall sensitivity, specificity and accuracy were 89.9%, 77.8% and 89.4%, respectively. Analysis of detection rate and SUV_max was performed in 209 confirmed lesions in 34 cases proved to be PHEOs or PGLs, 188 lesions (89.95%) were detected by ⁶⁸Ga-DOTA-NOC PET/CT, SUV_max was 14.69±16.12. 62 bone metastasis in 13 patients were (62/64,96.9%) and 46 metastatic lymph nodule(46/46, 100%) in 13 patients showed high expression of SSTR, SUV_max was 15.92±14.42 and 23.14±19.84,respectively. 68Ga-DOTANOC PET/CT showed higher sensitivity in the detection of lymphadenopathy, remote and visceral metastasis. No significant adverse events were observed in 10 patients after 177Lu-DOTA-TATE therapy, function related symptom and hypertension was significantly released associated with significant reduction of catecholamine and serum CGA. ⁶⁸Ga-DOTA-NOC PET/ CT shows higher sensitivity in the detection of bone metastasis and lymphadenopathy in PHEOs/PGLs, which has great merits for staging and risk stratification of PHEOs/PGLs. PRRT have good response especially in symptom release and quality of life improvement and is tolerable with no evident hematological events and kidney toxicity. Furthermore, present study will pave the way for SSA based theranostics on PHEOs/PGLs. (author)