Irinotecan and temozolamide treatment for relapsed Ewing sarcoma: A single-center experience and review of the literature

Long-term survival in relapsed Ewing sarcoma (ES) is less than 20%. Encouraging results have been reported with irinotecan and temozolomide combinations (IRN/TMZ). We aimed to share our experience and compare it with previously published studies using this combination to treat relapsed ES. We retrospectively evaluated 20 patients treated with a combination of IRN (20 mg/m²/d × 5 for 2 weeks) and temozolomide (100 mg/m²/d × 5). Patients received a total of 97 courses. An objective response was achieved in 11 patients (55%) and maintained for a median of 12 months. Five patients were alive for amedian of 12 months. Median time to progression was 5.5 (2-57) months. After the IRN/TMZ treatment, 1-year overall and event-free survival rates were 54.2% and 44.4%, respectively. Grade 3-4 toxicities included diarrhea (9.2%), neutropenia (11.3%), and thrombocytopenia (6.2%). Three retrospective trials were found in our literature review, which used an IRN/TMZ combination to treat ES. There was one other study which retrospectively evaluated the efficacy of vincristine, IRN, and TMZ combination in relapsed ES. A total of 81 patients were treated with IRN/TMZ in four studies including ours. The objective response rate was 55.1%, and median time to progression ranged from 5.5 to 8.3 months. Twenty-six (7.5%) of a total of 346 courses were associated with grade 3-4 diarrhea. Grade 3-4 neutropenia and thrombocytopenia were reported in 9.2% and 7.2% of the courses, respectively. Results showed that an IRN/TMZ combination is effective and tolerable in patients with relapsed ES.