The goal of this investigation was to determine if comparing sites of neuroblastoma at relapse after myeloablative chemoradiotherapy and purged autologous bone marrow transplantation (ABMT) with sites of disease at diagnosis and before ABMT could provide insight to the reasons for treatment failure.

Ninety-nine patients with high-risk neuroblastoma underwent ABMT after induction chemotherapy, surgery +/- local radiation (RT) and then myeloablative therapy with teniposide (or etoposide), melphalan, doxorubicin, cisplatin, and total-body irradiation (TBI).

Forty-one of 84 assessable patients (15 toxic deaths) developed progressive disease 1 to 44 months after ABMT. The overall probability of relapse 36 months after ABMT was 49%. Tumor recurred in primary (n = 22), bone (n = 20), bone marrow (n = 18), lung (n = 3), and other sites (n = 9). Eight patients relapsed in the primary site alone, 14 in primary and distant sites, and 19 in distant sites only. Of 41 patients with progressive disease, 33 have died, with a median interval from relapse to death of 4 months. Both bone and bone marrow involvement at diagnosis correlated with specific relapse in that site (P < .05). Bone marrow tumor content at harvest greater than 0.1% also correlated with bone marrow relapse (P = .001). There was an association between incomplete resection of the primary tumor at diagnosis and relapse in that site (P = .06).

Neuroblastoma normally recurs in multiple sites after ABMT, particularly in areas of previous disease. More intensive treatment to known areas of disease (aggressive early surgery, effective myeloablative consolidation therapy) and post-ABMT therapy for minimal residual disease should be studied for their potential to decrease the frequency of relapse.