Clinical Significance of Random Urinary Vanillylmandelic Acid in Patients with Neuroblastoma

Background: To evaluate the value of random urinary vanillylmandelic acid (VMA) as a surrogate marker for monitoring tumor response and predicting outcome in patients with neuroblastoma (NB). Methods: Medical records of 91 patients newly diagnosed with NB at the Samsung Medical Center between June 2014 and August 2017 were reviewed. Clinical associations and other prognostic factors, including age at diagnosis, stage, pathologic subtype, MYCN amplification, and other cytogenetic aberrations, were analyzed. Furthermore, the significance of random urinary VMA level in predicting outcome and tumor response was also evaluated. Results: The median random urinary VMA level at diagnosis was 27.9 (range: 1.7-600) mg/g creatinine. Abdominal primary site, male sex, advanced stage, less differentiated pathology (poorly differentiated, undifferentiated), 11q deletion, and high-risk tumor were associated with a higher VMA level at diagnosis. The VMA level decreased during chemotherapy (28.4%, 16.9%, and 9.6% of the VMA level at diagnosis after 3, 6, and 9 cycles of chemotherapy, respectively). A higher VMA level at diagnosis tends to be associated with a better overall survival in high-risk patients with borderline significance (58.3±18.6% vs. 76.5±13.4%, P=0.050). However, in the multivariate analysis, the VMA level was not a significant predictor of survival. A slower reduction in VMA level during chemotherapy was not associated with a worse overall survival. However, event free survival was significantly better in the rapid responder group. Conclusion: A higher VMA level was associated with high-risk features at diagnosis of NB. Random urinary VMA is a valuable marker for monitoring NB response during chemotherapy. KCI Citation Count: 0