Background: Asymptomatic carriers of germ line succinate dehydrogenase mutations need life-long surveillance for the development of pheochromocytomas and paragangliomas. However there is no consensus about an appropriate surveillance strategy. The aim of this study was to describe the long-term outcomes of a cohort of succinate dehydrogenase mutation carriers followed in our risk management clinic.
Method: Forty nine patients were included in the study. All patients were seen atleast once at the risk management clinic and had a minimum of one surveillance scan. Of these 12 were index cases (9 SDHB, 3 SDHD) and 37 were mutation-positive asymptomatic carriers (22 SDHB, 9 SDHD, 6 SDHC). Patients were followed for a mean of 4.4 (range 1-10) years. All patients underwent biennial MRI imaging of neck, thorax, abdomen and pelvis and annual clinic review and metanephrine testing.
Results: A total of 16 paragangliomas (10 SDHB, 6 SDHD) and 1 renal cell carcinoma (SDHB) occurred in the 12 index cases (9 SDHB, 3 SDHD). Two index patients with SDHB related paragangliomas had metastases on the initial scan. One SDHB and SDHD index patients developed additional tumours during surveillance. Among the asymptomatic carriers a total of 23 paragangliomas (22 SDHD and 1 SDHC) were detected in 8 (16%, 7 SDHD, 1 SDHC) patients. Of these 15 were detected on the first surveillance scan (14 SDHD, 1 SDHC) and 8 (all SDHD) were detected on subsequent scans. One non-index patient with SDHD mutation developed a liver metastases during surveillance. Of the seven asymptomatic carriers with SDHD mutations who had tumours on the initial surveillance scan six had the c.274G>T exon mutation in the SDHD gene.
Conclusions: Biennial MRI scans appears to be an effective surveillance strategy in the long-term follow up of patients with succinate dehydrogenase mutations, including those with SDHB.