Outcomes of patients with metastatic phaeochromocytoma and paraganglioma: A systematic review and meta-analysis

Objective: The outcomes of patients with metastatic phaeochromocytoma (PHEO) and paraganglioma (PGL) are unclear. We performed a systematic review and meta-analysis of baseline characteristics and mortality rates of patients with metastatic PHEO and PGL (PPGL). Design: Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, Scopus, Web of Science, and references of key articles were searched from inception to 2016. Patients: Studies comprised 20 patients with metastatic PPGL and reported baseline characteristics and follow-up data. Measurements: Reviewers extracted standardized data and assessed risk of bias using a modified Newcastle-Ottawa tool. Random-effects meta-analysis was used to pool event rates across studies. Results: Twenty retrospective noncomparative studies reported on 1338 patients with metastatic PHEO (685/1296, 52.9%) and PGL (611/1296, 47.1%), diagnosed at a mean age of 43.95.2years. Mean follow-up was 6.3 +/- 3.2years. Of 532 patients with reported data, 40.4% had synchronous metastases. Five-year (7 studies, n=738) and 10-year (2 studies, n=55) mortality rates for patients with metastatic PPGL were 37% (95% CI, 24%-51%) and 29% (95% CI, 17%-42%), respectively. Higher mortality was associated with male sex (RR 1.50; 95% CI, 1.11-2.02) and synchronous metastases (RR 2.43; 95% CI, 1.01-5.85). Conclusions: Available low-quality evidence from heterogeneous studies suggests low mortality rates of patients with metastatic PPGL. Male sex and synchronous metastases correlated with increased mortality. The outcomes of patients with metastatic PPGL have been inadequately assessed, indicating the need for carefully planned prospective studies.