Favorable local control from consolidative radiotherapy in high-risk neuroblastoma despite gross residual disease, positive margins, or nodal involvement
Menée à partir de données portant sur 67 patients pédiatriques atteints d'un neuroblastome à haut risque de récidive traité par chirurgie entre 2003 et 2014 (âge médian : 3,3 ans ; durée médiane de suivi : 4,5 ans), cette étude évalue, en fonction de la dose de rayonnements administrée et de critères pathologiques (présence d'un envahissement ganglionnaire, d'une maladie résiduelle ou de marges de résection positives), l'effet d'une radiothérapie de consolidation sur le contrôle de la maladie et la survie des patients
Purpose : Radiotherapy (RT) has an established role in consolidative treatment of high-risk neuroblastoma. In addition to the standard 21.6 Gy delivered to the primary site following surgical resection, recent cooperative group guidelines incorporate a 14.4 Gy boost in the instance of residual gross disease. Here we report the influence of RT dose and surgical pathology variables on disease control and overall survival (OS) in patients treated at a single institution. Methods : We conducted a retrospective study of 67 high-risk neuroblastoma patients who received RT as part of definitive management from January 2003 until May 2014. Results : At a median follow-up of 4.5 years, 26 patients (38.8%) failed distantly; 4 of these patients also failed locally. One patient progressed locally without distant failure. Local control was 92.5% and total disease control was 59.5%. No benefit was demonstrated for RT doses over 21.6 Gy with respect to local relapse-free survival (LRFS) (p = 0.55), disease-free survival (DFS) (p = 0.22) or OS (p = 0.72). With respect to LRFS, DFS, and OS, no disadvantage was seen for positive lymph nodes on surgical pathology, positive surgical margins, or gross residual disease. Of the patients with gross residual disease, 75% (6/8) went on to have no evidence of disease at time of last follow-up, and the two patients that failed did so distantly. Conclusions : Patients with high-risk neuroblastoma in this series maintained excellent local control, with no benefit demonstrated for radiation doses over 21.6 Gy, and no disadvantage demonstrated for gross residual disease following surgery, positive surgical margins, or pathologic lymph node positivity. Though the limitations of a retrospective review for an uncommon disease must be kept in mind, with small numbers in some of the subgroups, it seems that dose escalation should be considered only in exceptional circumstances.