Table 1.

Main studies on clinical predictors of metastatic disease/recurrence in PPGL. Abbreviations: PCC, pheochromocytoma; PGL, paraganglioma; PPGL, pheochromocytoma/paraganglioma; DA, dopamine; CgA, chromogranin A; NE, norepinephrine; E, epinephrine; VMA, vanillylmandelic acid; MN, metanephrine.

First Author, Year	Type of Study	Population	Patients	Outcomes	Clinical Predictors
John, 1999 [39]	Retrospective	PCC	86	Metastatic disease	Higher DA; extra-adrenal location; high tumor weight
Rao, 2000 [32]	Retrospective	PCC	27	Metastatic disease	Higher CgA; higher NE; lower E
Van der Harst, 2000 [26]	Retrospective	PCC	87	Metastatic disease	Higher DA; higher NE; lower ratio E/E + NE
Amar, 2005 [35]	Retrospective	PPGL	192	Recurrence	Younger age; familial disease;tumor site and size
Ayala-Ramirez, 2011 [10]	Retrospective	PPGL	371	Metastatic disease	Larger tumor size;extra-adrenal location
Park, 2011 [33]	Retrospective	PCC	152	Metastatic disease	Tumor > 5.5 cm; lower E, NE, VMA
Feng, 2011 [36]	Retrospective	PCC	136	Metastatic disease	Tumor > 5cm; multifocal and extra-adrenal tumors; higher MN
Eisenhofer, 2012 [28]	Retrospective	PPGL	365	Metastatic disease	Higher methoxytyramine; SHDB mutation; tumor > 5 cm;extra-adrenal location
De Wailly, 2012 [38]	Retrospective	PCC	53	Metastatic disease	Larger tumor size andhigher tumor weight
Press, 2014 [34]	Retrospective	PCC	135	Recurrence	Tumor > 5 cm
Kim, 2016 [23]	Retrospective	PPGL	223	Metastatic disease and/or recurrence	Younger age; germline mutations
Assadipour, 2017 [37]	Retrospective	PPGL	256	Metastatic disease and/or recurrence	SDHB mutation; tumor size
Hescot, 2019 [4]	Retrospective	PPGL	169	Metastatic disease	SDHB mutations
Parasiliti-Caprino, 2020 [14]	Retrospective	PPGL	242	Metastatic disease and/or recurrence	Genetic mutations; younger age; larger tumor size
Li, 2021 [21]	Retrospective	PPGL	249	Metastatic disease	Genetic mutations; lower E