Comparison of Clinical Features and Outcomes in Patients With Bilateral Versus Unilateral Adrenal Neuroblastoma

Background: While nearly half of cases of neuroblastoma arise in one of the adrenal glands, bilateral origin is rare. We aimed to compare clinical characteristics and outcomes between patients with bilateral versus unilateral adrenal neuroblastoma. Procedure: We utilized the Surveillance, Epidemiology, and End Results database to identify patients with bilateral and unilateral adrenal neuroblastoma from 1973 to 2012. We used Fisher exact tests to compare demographics and clinical features between groups. We used Kaplan-Meier methods to describe the 5-year overall survival rate for these 2 groups. We conducted a literature review to complement the Surveillance, Epidemiology, and End Results data. Results: Of 1617 patients in the cohort, 1585 (98%) had unilateral disease and 32 (2%) had bilateral disease. Compared with patients with unilateral disease, a significantly greater proportion of patients with bilateral disease was below 1 year of age (53.1% vs. 31.8%; P = 0.01) and had distant metastasis at diagnosis (90.6% vs. 69.0%; P = 0.006). The 5-year overall survival rate for patients diagnosed with bilateral disease was 70.5% (95% confidence interval, 45.1%-85.8%), compared with 62.4% (95% confidence interval, 59.7%-65%) for patients with unilateral disease (P = 0.26). Conclusions: Compared with patients with unilateral disease, patients with bilateral adrenal neuroblastoma are younger, more likely to have distant metastasis, and have a favorable outcome.