Clinical analysis and prognostic factors in children with neuroblastoma-associated opsoclonus-myoclonus syndrome: a multicenter retrospective study

The long-term neurological outcomes for children diagnosed with neuroblastoma associated with Opsoclonus Myoclonus Syndrome (NB-OMS) are not well characterized, primarily due to the infrequency of the condition. This multicenter study sought to evaluate the rate of neurological recovery and the long-term neurodevelopmental sequelae within this patient population.

A retrospective study at nine Chinese medical centers (January 2015 - January 2025) involved 39 children with NB-OMS. Researchers gathered data on demographics, clinical presentation, tumor traits, treatment, and outcomes. Non-parametric tests and multivariate logistic regression identified prognostic factors.

In this study, a cohort of 39 patients was examined, with a median age at onset of 22 months. The retroperitoneum was identified as the most prevalent tumor location, accounting for 79.5% of cases. The majority of tumors were classified within the low-risk and intermediate risk, as determined by the International Neuroblastoma Risk Group Staging System, comprising 87.2% of the sample. Follow-up was conducted for 37 patients, all of whom exhibited symptom improvement, resulting in a 100% survival rate. Nonetheless, neurological sequelae were detected in 16 children (43.2%). A higher OMS severity score at onset demonstrated a strong trend towards significance (OR = 1.42, 95% CI: 1.00-2.01, P = 0.051). Multivariate analysis revealed that delayed initiation of treatment, defined as greater than 30 days, was a significant independent risk factor for the development of sequelae (Odds Ratio [OR] = 22.98, 95% Confidence Interval [CI]: 2.67-197.63, P = 0.004). Additionally, relapse of opsoclonus-myoclonus syndrome emerged as a significant independent risk factor (OR = 13.74, 95% CI: 1.37-137.34, P = 0.026). Furthermore, the use of combination immunotherapy, consisting of corticosteroids and intravenous immunoglobulin (IVIG), was associated with a significantly reduced median time to symptom resolution compared to non-combination therapy (5 months versus 8.5 months, P = 0.001).

OMS is a chronic immune disorder often misdiagnosed, leading to treatment delays. Prompt first-line immunotherapy can quickly alleviate OMS symptoms. Early treatment and reducing relapses are crucial for better long-term outcomes. Future multicenter studies are needed to confirm the effectiveness of new immunotherapies.