Post-operative Radiotherapy in Poor Responders Ewing's Sarcoma Patients

Local recurrence after surgical resection is a complex phenomenon. An important predictive factor is the response to chemotherapy. Central site of disease may be a second independent predictive factor (Lin et al. 2007). Patients with more than 10% viable tumour cells at surgery following neo-adjuvant chemotherapy had a less favourable outcome with an Event-free Survival [EFS] of 47% after 10 years. Patients with good histological response (< 10% viable tumour cells) after chemotherapy alone had a prognosis of about 70% after 10 years. However, further studies are necessary to determine the merit of adjuvant radiation for high-risk patients (poor responders). Taking into consideration that the toxicity and morbidity of combined surgery and radiation is greater than either alone and must be closely monitored.

this study arm will take External Beam radiotherapy as follows : Radiotherapy Technique: Conformal radiotherapy, Intensity modulated radiotherapy [IMRT] is allowed. Radiotherapy Dose: 45 Gy/25 fractions/5 weeks (1.8 Gy/fraction). , the inclusion criteria are as following: Age < 18 years old. Non-metastatic Ewing Sarcoma patients who will undergo surgery and show poor histologic response to neo-adjuvant chemotherapy. Negative surgical margins. Patients show good safety profile and acceptable performance status.

this arm will not take radiotherapy and their inclusion criteria as following: Age < 18 years old. Non-metastatic Ewing Sarcoma patients who will undergo surgery and show poor histologic response to neo-adjuvant chemotherapy. Negative surgical margins. Patients show good safety profile and acceptable performance status.

Determine whether the administration of post-operative radiotherapy for poor responder Ewing Sarcoma patients to neo-adjuvant chemotherapy and radical surgery, leads to improved Local Relapse-free Survival (LRFS).

Inclusion Criteria: Age < 18 years old. Non-metastatic Ewing Sarcoma patients who will undergo surgery and show poor histologic response to neo-adjuvant chemotherapy. Negative surgical margins. Patients show good safety profile and acceptable performance status. Exclusion Criteria: Patients who show progressive disease and undergo surgery before the time of local control. Patients who undergo Amputation or Rotationplasty will be excluded. Post-surgical complications that may hinder the administration of radiotherapy