Minimal disease detection in peripheral blood and bone marrow from patients with non-metastatic neuroblastoma.

PURPOSE: In non-metastatic neuroblastoma (NB), the identification of the cases that require more intensive treatment is still difficult. Minimal disease (MD) and minimal residual disease (MRD) detection in outcome prediction seems to be important in advanced neuroblastoma, but there are not many studies focused on patients with non-metastatic disease. The aim of this study was to determine whether the presence of MD detected at diagnosis could be associated with bad prognosis. PROCEDURES: Quantitative reverse transcriptase-polymerase chain reaction QRT-PCR was performed on peripheral blood (PB) and bone marrow (BM) samples from patients with non-metastatic NB at diagnosis for tyrosine hydroxylase (TH) and doublecortin (DCX) mRNAs detection.
RESULTS: The frequencies of detecting MD in our series of 102 patients with non-metastatic NB were as follows: 6.2% (5/81) PB samples and 10.6% (10/94) BM samples. Overall survival was similar for patients who expressed or not the MD biomarkers at diagnosis. However, patients with MD detected in PB showed lower EFS than patients with negative PB (P = 0.038).
CONCLUSIONS: Minimal disease detection in PB seems to be useful for predicting relapse probabilities in patients with non-metastatic NB. The stages 1 and 2 patients with neuroblastoma showed high survival rates, and MD was detected in a small number of patients probably being non-contributory for predicting patient outcome. For stage 3 patients with NB, MD detection by QRT-PCR in PB at diagnosis could be useful for predicting outcome and for early and sensitive detection of relapsing disease.