Clinical risk factors for malignancy and overall survival in patients with pheochromocytomas and sympathetic paragangliomas: primary tumor size and primary tumor location as prognostic indicators.

Abstract

Pheochromocytomas and sympathetic paragangliomas are rare neuroendocrine tumors for which no precise histological or molecular markers have been identified to differentiate benign from malignant tumors. The aim was to determine whether primary tumor location and size are associated with malignancy and decreased survival. We performed a retrospective chart review of patients with either pheochromocytoma or sympathetic paraganglioma. The study group comprised 371 patients. Overall survival and disease-specific survival were analyzed according to tumor size and location. Sixty percent of patients with sympathetic paragangliomas and 25% of patients with pheochromocytomas had metastatic disease. Metastasis was more commonly associated with primary tumors located in the mediastinum (69%) and the infradiaphragmatic paraaortic area, including the organ of Zuckerkandl (66%). The primary tumor was larger in patients with metastases than in patients without metastatic disease (P < 0.0001). Patients with sympathetic paragangliomas had a shorter overall survival than patients with pheochromocytomas (P < 0.0001); increased tumor size was associated with shorter overall survival (P < 0.001). Patients with sympathetic paragangliomas were twice as likely to die of disease than patients with pheochromocytomas (hazard ratio = 1.93; 95% confidence interval = 1.20-3.12; P = 0.007). As per multivariate analysis, the location of the primary tumor was a stronger predictor of metastases than was the size of the primary tumor. The size and location of the primary tumor were significant clinical risk factors for metastasis and decreased overall survival duration. These findings delineate the follow-up and treatment for these tumors.