TNM Staging and Overall Survival in Patients with Pheochromocytoma and Sympathetic Paraganglioma

Context: Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumors. Metastases develop in 15% to 20%. The American Joint Committee on Cancer (AJCC) established inaugural guidelines for PPGL tumor-node-metastasis (TNM) staging. Objective: The objective of this analysis is to investigate the associations between TNM staging and overall survival (OS). Methods: We retrospectively applied the TNM staging at the time of diagnosis of the primary tumor. The primary outcome was OS. Unadjusted survival rates were estimated by the Kaplan–Meier method. Cox proportional hazards regression models were used to evaluate the associations between OS and covariates of interest. Results: The study included 458 patients. Median OS was 18.0 (95% CI, 15.6-not reached) years. At diagnosis, 126 (27.5%) tumors were stage I, 213 (46.5%) were stage II, 47 (10.3%) were stage III, and 72 (15.7%) were stage IV. The 10-year OS probabilities were 0.844 (95% CI, 0.768-0.928) for patients with stage I tumors, 0.792 (95% CI, 0.726-0.865) for stage II, 0.595 (95% CI, 0.435-0.813) for stage III, and 0.221 (95% CI, 0.127-0.384) for stage IV. Compared with stage I, the hazard ratios (HR) for death were 1.50 (0.87-2.57) for stage II, 2.85 (1.45-5.63) for stage III, and 8.88 (5.16-15.29) for stage IV (P < 0.001). Compared with patients with no germline mutations, those with RET 634/918 had better OS (HR: 0.28; 95% CI, 0.12-0.69). Other germline mutations, including SDHB, did not exhibit worse OS than patients with metastasis and sporadic disease. Conclusion: OS rates correlated with the recently developed AJCC TNM staging and were not worse in hereditary disease. Stage IV disease exhibited a significantly shorter OS compared with stages I-III. Future staging systems could be adjusted to better separate stages I and II.