The degree of tumor volume reduction during the early phase of induction chemotherapy is an independent prognostic factor in patients with high-risk neuroblastoma.

BACKGROUND: In patients with high-risk neuroblastoma, the reduction in primary tumor volume was measured during the early phase of induction chemotherapy as an indicator of early tumor response, and the authors investigated whether the degree of tumor volume reduction could predict outcome in these patients.
METHODS: Primary tumor volumes were measured both at diagnosis and at the first tumor response evaluation (after 2 or 3 cycles of induction chemotherapy) in 90 patients with high-risk neuroblastoma who had volumetrically evaluable computed tomography or magnetic resonance scans. If the tumor volume at the first response evaluation was >40% of the initial tumor volume, then the patient was categorized as a poor responder; otherwise, the patient was categorized as a good responder. Outcomes were compared according to the degree of tumor volume reduction at the first response evaluation.
RESULTS: The tumor volume reduction was greater in patients who remained relapse free than in patients who had a relapsed tumor (median percentage tumor volume, 21% vs 41.5%; P = .037). The 5-year relapse-free survival rate was higher in the good responders than in the poor responders (83% [95% confidence interval, 72%-94%] vs 51% [95% confidence interval, 31%-71%]; P = .002). In a multivariate analysis of relapse-free survival, a poor early response was identified as an independent, unfavorable prognostic factor (hazard ratio, 4.24; 95% confidence interval, 1.59-11.29; P = .004).
CONCLUSIONS: A greater reduction in tumor volume reduction the early phase of induction chemotherapy was associated with a better outcome in patients with high-risk neuroblastoma. Tailoring treatment intensity according to the early tumor response to induction chemotherapy may improve patient outcomes.