Ewing's Sarcoma with Non-Sacral Pelvic Primary: Treatment After First-Line Chemotherapy Failure

This protocol addresses relapsed Ewing's sarcoma in patients whose primary tumour is localised to a non-sacral pelvic site and who did not achieve the required response to initial induction chemotherapy and local treatment.

Clinical scenario

The primary tumour is located in the non-sacral pelvis. For this localisation, adjuvant radiotherapy is an important component of local control regardless of surgical margins, tumour volume, or histological response, as it has been associated with superior local control and survival outcomes compared with surgery alone.

When first-line treatment was not sufficient

Prior therapy: Neoadjuvant induction chemotherapy with interval-compressed VDC/IE regimen (vincristine, doxorubicin, cyclophosphamide alternating with ifosfamide, etoposide), followed by local treatment (surgery and/or definitive radiotherapy) and consolidation chemotherapy. Alternative regimens include VIDE induction (vincristine, ifosfamide, doxorubicin, etoposide) with VAI or VAC consolidation.

Goals not reached that escalate to this protocol: Complete histological tumour response (100% necrosis, fibrosis, and calcification) on surgical specimen assessment, and adequate reduction in size of the soft tissue mass on MRI.

Next-line approach

For relapsed Ewing's sarcoma following first-line treatment, second-line chemotherapy involves combinations of alkylating agents and topoisomerase inhibitors, among other regimens — the specific choice is guided by individual patient factors detailed in the full protocol.

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References

DOI: 10.1016/j.annonc.2021.08.1995

Also, adjuvant RT should be considered in patients with non-sacral pelvic ES regardless of surgical margins, tumour volume or histological response, as this was shown to have superior local control and survival outcomes compared with surgery alone [II, B].

ChT regimens for relapsed ES are not standardised and include alkylating agents (cyclophosphamide and ifosfamide) in combination with topoisomerase inhibitors (etoposide and topotecan), irinotecan with temozolomide, gemcitabine and docetaxel, high-dose ifosfamide or carboplatin with etoposide [III, B].

Preliminary results from the rEECur study, the first randomised, controlled trial in this setting, suggest gemcitabine and docetaxel to be the inferior regimen, with temozolomide plus irinotecan also inferior to topotecan plus cyclophosphamide and high-dose ifosfamide.

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