Cumulative incidence of TA-TMA in neuroblastoma patients according to pretransplant allocation (n = 72). Seventy-two patients underwent autologous HSCT for neuroblastoma; 21 (29%) were scheduled for single transplant and 51 (71%) were scheduled for tandem transplant. No patient developed TA-TMA from the single transplant cohort; 6 (29%) were diagnosed with VOD. No patients allocated to a single transplant had a delay in radiation, and 1 patient had a delay in antibody therapy (unknown reason). Thirteen (25%) of the patients who were scheduled to undergo a tandem transplant developed TA-TMA (1 after HSCT #1, 12 after HSCT #2), and 5 (10%) developed VOD. Three patients did not receive HSCT #2: 1 because of TA-TMA, 1 developed VOD, and 1 had disease relapse. Nine patients (18%) had a delay in receiving radiation (5 with TA-TMA, 2 with TA-TMA + VOD, 2 with VOD), and 9 patients (18%) had a delay in antibody therapy (7 with TA-TMA, 1 with TA-TMA + VOD, 1 with VOD). Bu, busulfan; CEM, carboplatin, etoposide, melphalan; Cy, cyclophosphamide; Mel, melphalan; Thio, thiotepa.