Staging in neuroblastoma has transitioned from INSS which is a pathological system to INRGSS which is based on CT and MRI imaging. The purpose of this study was to look at the best way to evaluate tumor response comparing serial measurements of 3 dimensions of lesions to calculate volume, to one dimension of the lesions as per Response Evaluation Criteria in Solid Tumors (RECIST). Response of ≥30% reduction in longest diameter was used for RECIST, ≥50% reduction in volume as per INRC or ≥60% reduction in volume (because 30% reduction in diameter corresponds to 60% reduction in volume of sphere).
Data from 229 children with high-risk neuroblastoma from 7 centers were analyzed. Sensitivity to detect response in survivors was higher for volume response measures than single measure but there was low specificity of all response evaluations (to detect poor response in those who died). None of the response measures predicted outcome or extent of resection.
* Volume or single diameter response measurements on imaging does not predict survival in high-risk neuroblastoma, but still remains important to monitor for progression and overall response to treatment. As it is more complex to do 3-dimension measurements, and there was no difference in outcome prediction, the revised International Neuroblastoma Response criteria will use RECIST criteria using longest diameter going forward in future studies.