Continuous 14 Day Infusional Ifosfamide for Management of Soft-Tissue and Bone Sarcoma: A Single Centre Retrospective Cohort Analysis

Abstract

Ifosfamide is used to treat soft-tissue sarcoma (STS) and bone sarcoma (BS), with improved efficacy at doses above 9 g/m2/cycle. To mitigate treatment-associated toxicity with higher doses, continuous infusional ifosfamide is increasingly used. However, clinical outcome data remain limited. Single-centre retrospective analysis of patients treated with four-weekly infusional ifosfamide (14 g/m2/14d) between August 2012 and February 2019 was conducted. Radiological response, progression-free survival (PFS), overall survival (OS) and toxicity were evaluated. Eighty patients were treated—46 with STS and 34 with BS. Patients received a median of three cycles of infusional ifosfamide (1–24). Overall disease control rate (DCR) in STS was 50% (23 of 46 patients), with a median PFS of 3.8 months, and median OS of 13.0 months. In synovial sarcoma (SS), DCR was 80% (12/15), median PFS 8.1 months and median OS 20.9 months. Overall DCR in BS (34 patients) was 30%, with a median PFS of 2.5 months and median OS of 6.2 months. Five patients (6%) stopped treatment due to toxicity alone within the first two cycles. A further 10 patients stopped treatment due to toxicity during later treatment cycles (12%) and 18 patients (23%) required dose modification. Forty-five patients (56%) experienced grade (G) 3/4 haematological toxicity, with 12 episodes of febrile neutropenia and one treatment-related death. Twenty-seven patients (34%) experienced G3/4 non-haematological toxicity, most commonly nausea and vomiting (10, 13%). In summary, infusional ifosfamide has efficacy in STS, most notable in SS. Benefit appears limited in BS. Treatment is associated with toxicity that requires specialist supportive care.