Tolerability of ifosfamide-containing regimen in patients with high-risk renal and INI-1-deficient tumors.

ABSTRACT

BACKGROUND: Outcomes for children with high-risk renal (HRR) and INI-1-deficient (INI-) tumors are unacceptably poor. Concerns about excessive toxicity-as many are infants and/or undergo nephrectomy-have resulted in decreased chemotherapy dosing and omission of the nephrotoxic drug ifosfamide in collaborative group studies. As cause of death for children with these cancers remains overwhelmingly more from progressive disease rather than treatment toxicity, we examined the tolerability of an intensive ifosfamide-containing regimen. PROCEDURE Retrospective review of children with HRR/INI- tumors treated at a single institution with vincristine, doxorubicin, cyclophosphamide alternating with ifosfamide, carboplatin, etoposide (VDC-ICE) from 2006-2016. The primary outcome was regimen tolerability, including kidney injury and grade 3-5 nonhematologic toxicities. RESULTS: Fourteen patients with a median age of 1.7 years (range 0.1-10.5) treated with VDC-ICE were identified. Diagnosis included malignant rhabdoid tumor (n = 9) (primary renal [n = 2]); diffuse anaplastic Wilms tumor (n = 3); clear cell sarcoma of the kidney (n = 1); and anaplastic chordoma (n = 1). All children with primary renal tumors (43%) underwent complete (n = 5) or partial nephrectomy (n = 1) before chemotherapy. Nine (64%) completed all intended cycles of chemotherapy; n = 5 (36%) did not due to disease progression. Unplanned hospitalizations occurred in 13 (93%) patients, most commonly for febrile neutropenia. No patient experienced severe organ toxicity, diminished renal function, treatment discontinuation due to toxicities, or treatment-related death. CONCLUSIONS: In children with HRR/INI- tumors, VDC-ICE chemotherapy was well-tolerated without excessive toxicities, even amongst young patients with solitary kidneys. Concerns about toxicity should not preclude an intensive ifosfamide-containing regimen from use in future trials in this population.