Purpose: On the assumption that most infants with disseminated neuroblastoma without MYCN amplification (MYCNA) have a favorable prognosis, two concomitant prospective trials were started in which chemotherapy was limited to patients presenting life- or organ-threatening symptoms or overt metastases to skeleton, lung, or CNS. Surgery was to be performed only in the absence of surgical risk factors.
Patients and methods: One hundred seventy infants with disseminated neuroblastoma without MYCNA, diagnosed between June 1999 and June 2004 in nine European countries were eligible for either of the two studies. Trial 99.2 included all stage 4S infants and those with stage 4 with a primary tumor infiltrating across the midline or positive skeletal scintigraphy who were to be observed in absence of symptoms. Trial 99.3 included infants with overt metastases to the skeleton, lung, and CNS to be treated with a minimum of four chemotherapy courses.
Results: The 125 infants treated on trial 99.2 had a 2-year overall survival (OS) of 97.6% with no difference between asymptomatic and symptomatic patients (97.7% v 97.3%), patients without or with unresectable primary tumors (96.8% v 100%), and patients without or with positive skeletal scintigraphy without radiologic abnormalities (97.2% v 100%). The 45 infants treated on trial 99.3 had a 2-year OS of 95.6%. No patients died of surgery- or chemotherapy-related complications.
Conclusion: Infants with disseminated disease without MYCNA have excellent survival with minimal or no treatment. Asymptomatic infants with an unresectable primary tumor or positive skeletal scintigraphy without radiologic abnormalities may undergo observation alone.