Stage 4N neuroblastoma before and during the era of anti-GD2 immunotherapy.

Abstract

10037 Background: Patients with stage 4N neuroblastoma (distant metastases limited to lymph nodes) stand out as virtually the only survivors of high-risk neuroblastoma (HR-NB) before myeloablative therapy (MAT) and immunotherapy with anti-GD2 monoclonal antibodies (mAb) became standard. No report presents results with contemporary treatment programs for 4N. The only large study to date (from the International Neuroblastoma Risk Group) analyzed patients diagnosed 1990-2002, found 4N to have significantly better event-free (EFS) and overall survival (OS) compared to other stage 4 patients, and recommended considering less intensive therapy for 4N. Methods: We conducted a retrospective analysis of patients treated at our center from 1985-2021 to analyze our large experience to fill the gap in the literature on treatment of 4N, namely, results with contemporary multi-modality therapy including MAT and anti-GD2 mAbs. Results: We found and reviewed 48 pediatric 4N patients ( < 18 years old) treated 1985-2021 at our center. Biological features included segmental chromosomal aberrations in 21/21 MYCN-non-amplified patients, mutations of ALK in 4/22 (18%), ATRX in 4/16 (25%), and TERT in 4/12 (33%) patients. Among 33 MYCN-non-amplified high-risk patients ( > 18 months old), 19 are relapse-free 1.6+-to-36.9+ (median 12.2+) years post-diagnosis, including 13 without prior MAT and 3 with no mAb, while 14 patients (7 without prior immunotherapy) relapsed (all in soft tissue initially). Eleven of the 14 died, including 3 who developed late osteomedullary metastases after 3-5 relapses in soft tissue alone. Of 13 MYCN-amplified 4N patients, 6 are relapse-free 4.5+-to-25.8+ (median 11.7+) post-diagnosis (all received mAbs; 3 underwent MAT) and 3 are in 2nd remission 4.4+-to-21.1+ years post-relapse (all soft tissue). For all high-risk 4N patients, 5/10-year EFS was 55%/52%, and OS was 76%/64%. MAT was not prognostic. The 2 patients with intermediate-risk 4N (14 months old) are relapse-free 7+ years post-resection of primary tumors; distant disease spontaneously regressed. Conclusions: The natural history of 4N is marked by NB confined to soft tissue without early relapse in bones or bone marrow, sites where mAbs have proven efficacy. These findings plus the possibility of survival without MAT and/or mAb immunotherapy, as seen elsewhere and at our center, support consideration of treatment reduction for selected MYCN-non-amplified 4N patients.