Neuroblastoma With Opsoclonus-Myoclonus Ataxia Syndrome: A 10-Year Experience From a Low- and Middle-Income Country Setting

Neuroblastoma (NB) associated with opsoclonus-myoclonus ataxia syndrome (NB-OMAS) has a favorable cancer prognosis but complicated long-term neurological sequelae. The aim was to evaluate the clinical profile and outcomes of NB-OMAS in children at a single tertiary care center in India. Children aged younger than 14 years with NB-OMAS treated between January 1, 2013 and December 31, 2022, were retrospectively analyzed. Among 189 children with NB, 12 (6.3%) had OMAS. The mean age at diagnosis was 17.17±5.35 months. All patients were either stage L1 or L2; 7 (58.3%) had NB diagnosed before 18 months of age, and 9/12 (75%) had low-risk NB. Ataxia (83.3%) and opsoclonus (66.6%) were common symptoms with a mean symptom duration of 12.08±12.05 months. The mean OMAS score significantly improved from 6.17±2.87 (baseline) to 0.75±1.21 (treatment completion) ( P =0.002). Immunosuppressive therapy (IST) was given for a mean duration of 15.14±6.59 months to 58.3% of patients. At a median follow-up of 16.5 months (range: 3 to 118 mo), 91.7% and 75% had complete remission of NB and OMAS, respectively. Higher OMAS scores at presentation predicted prolonged symptoms ( P =0.001) and incomplete OMAS response ( P =0.048). Four (33%) had developmental delay at the last follow-up. In an LMIC setting, NB-OMAS has excellent oncological outcomes, but long-term neurological challenges remain, especially for children with a high OMAS score.