Impact of surgical resection for subdiaphragmatic paragangliomas.

Background: Subdiaphragmatic paraganglioma is a rare neuroendocrine tumor for which scarce data exist regarding long-term patient outcome following resection. The aim of this study was to determine the association of surgical resection with survival.

Methods: A retrospective study at a tertiary care center was performed. Demographics, genetics, histology, and operative details were reviewed. Patients were grouped according to margin status (R0, R1, or R2) and survival calculated.

Results: A total of 50 patients with subdiaphragmatic paragangliomas underwent primary resection from 1999 to 2012. Median age at operation was 46 years, with a median tumor size of 6.0 cm. Of these patients, 30 (60 %) had a R0 resection, 11 (22 %) had a R1 resection, and 9 (18 %) had a R2 resection. There was no operative mortality, and 17 (34 %) patients had metastatic disease. Six (12 %) patients died, four (8 %) of whom had metastatic disease. Univariate analysis identified that age >50 years (p = 0.02) and undergoing a R2 resection (p = 0.03) were associated with a shorter overall survival (OS). Those with metastases at some point after their initial diagnosis had a shorter disease-free survival (DFS) than those without metastases (p = 0.04). Of 27 patients tested, 12 (44 %) had a germline succinyl dehydrogenase B (SDHB) mutation. SDHB immunohistochemistry identified 18 patients (of 27 who underwent staining) who had loss of SDHB expression in which 7 of 11 patients (63 %) who underwent genetic testing had a genetic mutation.

Conclusions: Surgical resection of subdiaphragmatic paraganglioma is safe. Survival was longest in patients who were younger, with no metastases, or had a R0 or R1 resection. Patients who test negative for a germline mutation should undergo SDHB immunostaining to identify potential hereditary carriers missed by current genetic testing.