Clinical significance of MYCN amplification in patients with high-risk neuroblastoma.

Background: This study investigated the clinical significance of MYCN amplification within high-risk neuroblastoma (NB).

Methods: Medical records of 135 patients who were diagnosed with high-risk NB from 2004 to 2016 were reviewed.

Results: Fifty-one (38%) patients had MYCN amplified tumors, and the remaining 84 (62%) had nonamplified tumors. MYCN amplification was associated with abdominal primary site, less differentiated pathology, higher levels of lactate dehydrogenase and neuron-specific enolase (NSE), lower vanillylmandelic acid level, and larger primary tumor volume at diagnosis. MYCN amplification was associated with a better early response (faster reduction of primary tumor volume and NSE level). The proportion of patients in complete response or very good partial response after induction treatment was relatively higher in MYCN amplified tumors than in nonamplified tumors; however, all progressions during induction treatment occurred only in MYCN amplified tumors (P = 0.007). The time to progression was shorter (median 1.5 years vs. 1.9 years, P = 0.037) and survival after relapse/progression was worse in MYCN amplified tumors (3 year overall survival: 7.7 ± 7.4% vs. 20.5 ± 8.8%, P = 0.046). There was no difference in event-free survival and overall survival between MYCN amplified and nonamplified tumors.

Conclusion: MYCN amplification was associated with more aggressive features at diagnosis and a better early response, but a higher progression rate during induction treatment and lower chance of survival after relapse/progression. There was no difference in survival rates according to MYCN amplification in patients with high-risk NB.