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Objective: Pheochromocytomas and paragangliomas (PPGLs) are rare tumors arising from the neural crest cells that form the sympathetic and parasympathetic nervous systems. Radiotherapy with [131I]metaiodobenzylguanidine (MIBG) is recommended for unresectable PPGLs. We investigated the usefulness of the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) derived from [18F]fluorodeoxyglucose-positron emission tomography (FDG-PET) for predicting the prognosis of patients with unresectable PPGL(s) before receiving [131I]MIBG therapy. Patients and methods: We retrospectively analyzed the cases of 25 patients with unresectable PPGLs treated with [131I]MIBG at our hospital between 2001 and 2020. The MTV and TLG were measured in reference to liver accumulation. We divided the patients into two groups based on median values for the maximum standardized uptake value (SUVmax), MTV, and TLG, and evaluated between-group differences using log-rank tests. Cox proportional hazards models were used to determine whether there were significant differences in prognosis with respect to tumor type (pheochromocytoma vs. paraganglioma), site of metastasis, age, past treatment (chemotherapy, external radiation or [131I]MIBG treatment before the current [131I]MIBG treatment), urinary catecholamine, SUVmax, MTV, and TLG. Results: The median follow-up time was 42 months (range 2–136 months). The median overall survival was 63 months. The overall survival (OS) was significantly shorter in the high-MTV group (log-rank test, p = 0.049) and the high-TLG group (p = 0.049), with no significant difference between the high- and low-SUVmax groups (p = 0.19). Likewise, there was no significant difference in prognosis according to pheochromocytoma or paraganglioma, metastasis location, age, or prior chemotherapy. A history of external radiation before [131I]MIBG treatment was associated with a significantly worse prognosis (hazard ration [HR] = 7.95, p = 0.0018). Urinary adrenaline and noradrenaline were not significant prognostic factors (p = 0.70, p = 0.25, respectively), but urinary dopamine did predict a worse outcome (p = 0.022). There was no increased risk of death for higher SUVmax or TLG (p = 0.63 and 0.057, respectively), but higher MTV did predict a worse outcome (HR = 7.27, p = 0.029). Conclusion: High MTV and high TLG were significantly associated with a poor prognosis after [131I]MIBG therapy for PPGLs. Other treatment strategies for such patients may need to be explored. [ABSTRACT FROM AUTHOR]

Objective FDG-PET has been shown useful in the staging of malignant lymphoma (ML) and in evaluating treatment outcomes. Serum concentration of soluble interleukin-2 receptor (sIL-2R) has also been shown prognostic in patients with MLs. This study analyzed the clinical possibility of baseline FDG-PET parameters, such as maximum standardized uptake values (SUV max ), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and serum sIL-2R and lactate dehydrogenase (LDH) concentrations, as prognostic variables in patients with oral and neck non-Hodgkin’s lymphoma (NHL). Methods Baseline FDG-PET parameters and serum protein concentrations were correlated with 2-year prognosis in 12 patients with oral and neck NHL. The optimal cutoff values for FDG SUV max, serum sIL-2R and LDH were determined by receiver operating characteristics analyses. Results At 2-year follow up, seven patients remained alive (good prognosis), and five had died (poor prognosis). The median FDG SUV max was significantly higher in the poor than in the good prognosis groups ( P  = 0.04), but serum sIL-2R concentrations did not differ significantly between the two groups ( P  = 0.09). Baseline MTV and TLG were significantly higher in patients with poor than with good prognosis ( P  = 0.02 each). Serum LDH levels was significantly higher in patients with poor than with good prognosis ( P  = 0.01). Univariate logistic regression analysis showed significant correlations between FDG SUV max and patient prognosis ( P  = 0.04, odds ratio, 23.4). Conclusion Comprehensive evaluation of baseline FDG SUV max may have possibility for predicting the prognosis of patients with oral and neck NHLs. [ABSTRACT FROM AUTHOR]