Comparison of Three Different Methods to Detect Bone Marrow Involvement in Patients with Neuroblastoma

Abstract Purpose Neuroblastoma (NB) is the most frequent solid malignancy in children outside the central nervous system. Detection of bone marrow (BM) involvement is crucial for correct staging and risk-adapted treatment. We compared three different methods regarding the detection of NB involvement in BM. Methods Eighty-one patients with NB were included in this retrospective study. BM samples were obtained at designated time points at study entry and during treatment or follow-up. The diagnostic tools for BM analysis included cytomorphology (CM), flow cytometry (FCM) and automatic immunofluorescence plus fluorescence in situ hybridization (AIPF). Results We analyzed 369 aspirates in 81 patients in whom AIPF, CM, and FCM were simultaneously available. During the observation period, NB cells were detected in 86/369 (23.3%) cases, by CM in 32/369 (8.7%) samples, by FCM in 52 (14.1%) samples, and by AIPF in 72 (19.5%) samples. AIPF and/or FCM confirmed all positive results obtained in CM and detected 11 additional BM aspirates with NB cells in 294 CM negative samples (p < 0,001). Survival of patients with BM involvement at entry into the study identified solely by FCM / AIPF was 17.4% versus 0% for patients in whom BM involvement was already identified by CM. Conclusion The combination of AIPF and FCM yielded the highest detection rate of NB cells in BM. AIPF was the single, most sensitive method in detecting NB cells in BM. Although CM did not contribute additional information, it is still a useful tool because of its rapid availability and cost-efficiency.