Autor:innen:
J. Kersting (Essen, DE)
A. Ranft (Essen, DE)
V. Bhadri (Sydney, AU)
B. Brichard (Brussels, BE)
S. Collaud (Essen, DE)
S. Cyprova (Prague, CZ)
H. Eich (Münster, DE)
T. Ek (Gothenburg, SE)
H. Gelderblom (Leiden, NL)
J. Hardes (Essen, DE)
L. Haveman (Utrecht, NL)
W. Hartmann (Essen, DE)
P. Hauser (Miskolc, HU)
H. Jürgens (Münster, DE)
J. Kanerva (Helsinki, FI)
T. Kühne (Basel, CH)
A. Raciborska (Warsaw, PL)
J. Rascon (D, LT)
A. Streitbürger (Essen, DE)
B. Timmermann (Essen, DE)
Y. Uhlenbruch (Bochum, DE)
P. Heesen (Essen, DE)
V. Rechl (Essen, DE)
U. Dirksen (Essen, DE)
Introduction
Radiotherapy (RT) is an integral part of Ewing Sarcoma (EWS) therapy. The Ewing 2008 protocol recommended radiotherapy doses ranging from 45 to 54 Gy. However some patients (pts) received other doses of RT. We analyzed the value of different radiotherapy doses on event-free survival (EFS) in EWS patients.
Methods
The Ewing 2008 database consists of 534 radiotherapy-admitted patients with non-metastatic EWS. Recommended treatment consisted of multimodal chemotherapy as well as local treatment consisting of surgery and (S&RT group)/or radiotherapy (RT group). EFS was analyzed with univariable and multivariable Cox regression models including known prognostic factors age, sex, tumor volume, surgical margins and histological response.
Results
S and RT was performed in 336 patients (70.4%), and 145 patients (29.6%) received definite RT. In the S&RT group radiotherapy dose was (a) < /= 53Gy in 193 (57.4%), (b) 54-58Gy in 118 (35.1%) and (c) > /= 59Gy in 25 (7.4%) pts. In the RT group radiotherapy dose was (a) in 17 (11.7%), (b) in 64 (44.1%) and (c) in 64 (44.1%) pts. 3y-EFS in the S&RT group was .76 (SE=.03) for (a), .76 (SE=.04) for (b), and .69 (SE=.10) for (c) (P=.57), and in the RT group .58 (SE=.13), .69 (SE=.06), and .73 (SE=.06) (P=.63), respectively. Multivariable Cox regression revealed age > /= 15 years (HR=2.3 95%CI 1.2-4.4), non-radical margins (HR=2.6 95%CI 1.4-5.0) for the S&RT group (Sex P=.81, Histological response P=.20, Tumor volume P=.13, Dose P=.35), and large tumor volume (HR 2.2 (95%CI 1.2-4.0) for the RT group as independent factors (Dose P=.15, Age P=.08, Sex P=.40).
Conclusion
No impact of RT dose on survival outcomes in our cohort was found, whether patients were treated with combined local therapy modality or definitive radiotherapy. The upcoming iEuroEwing trial will assess the value of different radiotherapy dose in a randomized manner to control for potential selection bias.