Opsoclonus Myoclonus Syndrome - Prognosis

Prognosis

Currently there are no clinically established laboratory investigations available to predict prognosis or therapeutic response.

Tumors in children who develop OMA tend to be more mature, showing favorable histology and absence of n-myc oncogene amplification than similar tumors in children without symptoms of OMA. Involvement of local lymph nodes is common, but these children rarely have distant metastases and their prognosis, in terms of direct morbidity and mortality effects from the tumor, is excellent. The three-year survival rate for children with non-metastatic neuroblastoma and OMA was 100% according to Children’s Cancer Group data (gathered from 675 patients diagnosed between 1980 to 1994); three-year survival in comparable patients with OMA was 77%. Although the symptoms of OMA are typically steroid-responsive and recovery from acute symptoms of OMA can be quite good, children often suffer lifelong neurologic sequelae that impair motor, cognitive, language, and behavioral development.

Most children will experience a relapsing form of OMA, though a minority will have a monophasic course and may be more likely to recover without residual deficits. Viral infection may play a role in the reactivation of disease in some patients who had previously experienced remission, possibly by expanding the memory B cell population. Studies have generally asserted that 70-80% of children with OMA will have long-term neurologic, cognitive, behavioral, developmental, and academic impairment. Since neurologic and developmental difficulties have not been reported as a consequence of neuroblastoma or its treatment, it is thought that these are exclusively due to the immune mechanism underlying OMA.

One study came to the conclusion that: Patients with OMA and neuroblastoma have excellent survival but a high risk of neurologic sequelae. Favourable disease stage correlates with a higher risk for development of neurologic sequelae. The role of anti-neuronal antibodies in late sequelae of OMS needs further clarification. Another study states that: Residual behavioral, language, and cognitive problems occurred in the majority.