Background:
Succinate dehydrogenase B (SDHB) and D (SDHD) mutations are associated with increased risk of paraganglioma. The approach for detecting incident disease continues to be refined with contemporary algorithms emphasising specialised imaging and biochemical studies. We examined the utility of chromogranin A (CgA) to predict composite paraganglioma surveillance outcome in patients with SDHB and SDHD mutation.
Methods:
A retrospective audit of patients (n=25, 40% female) with SDHB (n=22) or SDHD (n=3) mutation who underwent composite surveillance for paraganglioma at our institution between 1 July 2011 and 30 May 2015. All patients had contemporary (within six months) measurement of CgA concentration. Composite surveillance for paraganglioma included measurement of urinary catecholamines, plasma metanephrines and 18F-FDG PET/CT scanning. Patients were considered positive for an abnormality if any one of the composite tests were positive.
Results:
There were seven positive composite results during the study period, four of whom had elevated CgA concentrations. CgA had a sensitivity of 57% and specificity of 78% for predicting a positive composite result. The positive and negative predictive value of raised or normal CgA concentrations were 50% and 82%, respectively. SDHD mutation carriers contributed to two of three false negative results. In patients with SDHB mutation the sensitivity and the negative predictive value of CgA were 80% and 93%, respectively.
Conclusion:
CgA is a useful component of SDHB surveillance, with a normal result indicative of negative findings on 18F-FDG PET/CT and catecholamine screening.