Irinotecan and temozolomide chemotherapy in paediatric and adult populations with relapsed Ewing Sarcoma

BACKGROUND

Irinotecan and temozolomide (IT) is a widely used regimen for relapsed Ewing sarcoma (ES), although studies are largely limited to paediatric populations.

METHODS

We retrospectively reviewed paediatric (< 18 years) and adult patients (≥ 18 years) treated with salvage IT at two institutions. Haematologic toxicities were graded according to common terminology criteria of adverse events. Survival was estimated by the Kaplan-Meier method and compared by the Log Rank test.

RESULTS

Fifty-three patients were treated with IT from Jan, 2010 to Dec, 2018 (n = 16 paediatric; n = 37 adult). IT was given as second-line (n = 34; 64%) or ≥ third-line (n = 19; 36%). There was no difference in ≥ grade 3/4 haematologic toxicity between paediatrics and adults (31% vs. 35% respectively; p = 0.76). The frequency of diarrhoea of any grade was similar (38% in each group). Of 43 patients assessable for response, 12 (28%) had objective response (1 CR, 11 PR), 12 (28%) stable disease and 19 (44%) disease progression. Objective response rate did not differ between the two groups (36% in paediatrics vs. 25% in adults; p = 0.47). Median PFS was superior in paediatrics vs. adults (7.4 vs. 2.2 months, p = 0.039).

CONCLUSION

Irinotecan and temozolomide (IT) chemotherapy has activity for relapsed ES, with favourable toxicity and equally observed objective responses in the paediatric and adult populations. The observed superior PFS for the paediatric cohort requires further confirmation in future studies.

Outcomes of extraskeletal vs. skeletal Ewing sarcoma patients treated with standard chemotherapy protocol

PURPOSE

To compare the outcomes of extraskeletal and skeletal Ewing sarcomas treated with standard chemotherapy protocol.

METHODS

We retrospectively collected data on primary localized skeletal and extraskeletal ES patients. Demographics and disease characteristics were compared between the two groups. The influence of presentation (skeletal vs. extraskeletal) on overall survival (OS) and local recurrence-free survival (LRFS) was assessed and compared by the log-rank test.

RESULTS

A total of 120 patients were included; 29 (24%) had extraskeletal and 91 (76%) had skeletal ES. All patients received vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide (VDC-IE) chemotherapy, with a plan for local control at week 12. At a median follow-up of 38 months, there was no difference in OS between skeletal and extraskeletal ES; 5-year OS 70% and 67% respectively, p = 0.96. Patients with extraskeletal ES had inferior 5-year LRFS compared to skeletal ES; 74% vs. 83%; p = 0.042. Local recurrence occurred at a higher frequency in the extraskeletal group; 28% vs. 11%, p = 0.034, although more extraskeletal patients received adjuvant radiotherapy; 73% vs. 36%, p = 0.01. Among patients who underwent surgery (n = 76), there was no difference in R0 resection rate (skeletal: 89%, extraskeletal: 86%, p = 0.52, or good ( ≥ 90%) tumor necrosis; skeletal: 54%, extraskeletal: 38%, p = 0.31.

CONCLUSION

Patients with localized extraskeletal ES have comparable OS outcomes to patients with skeletal ES utilizing the standard VDC-IE chemotherapy. However, extraskeletal patients are at significantly higher risk for local recurrence.