Background: Opsoclonus-myoclonus syndrome (OMS) is a rare complication of neuroblastoma; however, its epidemiology, effective therapy and long-term outcome remain unclear. We herein investigated the clinical features and long-term outcome of OMS in Japan in order to determine effective therapy.
Methods: We retrospectively reviewed neuroblastoma patients registered in the Japan Neuroblastoma Study Group (JNBSG) between 1998 and 2013.
Results: The total number of registered neuroblastoma cases was 1,682 cases, and 53 cases had OMS (3.2%). The onset age of those 53 neuroblastoma patients ranged from 7-67 months, with a mean age of 21.4 months. These cases were assigned to stage 1, 47.1%; stage 2A/2B, 22.6%; stage 3, 15.1%; stage 4, 9.4%; and stage 4s, 0%. Only one case died. The treatment rates for OMS were oral prednisolone (60.3%), intravenous immunoglobulin (49.1%), methylprednisolone pulse therapy (37.7%), rituximab (11.3%), and adrenocorticotrophic hormone (ACTH) therapy (7.5%). Finally, the symptoms of OMS disappeared in 33 cases (62.3%), but remained in 20 cases (37.7%). There were no significant differences in the onset age of neuroblastoma between cases with disappeared symptoms and cases with remained symptoms (22.6 and 19.5 months, respectively). The rate of therapy, which included chemotherapy for neuroblastoma and therapy for OMS, in cases with disappeared symptoms was higher than that of the remained symptoms cases.
Conclusion: The prognosis of neuroblastoma patients with OMS is good, however, neurological symptoms can remain in a great number of patients. Therefore, chemotherapy and immunological therapy is necessary for improvement in the neurological prognosis.