Impact of radiotherapy parameters on outcome for patients with supratentorial primitive neuro-ectodermal tumours entered into the SIOP/UKCCSG PNET 3 study

Roger E. Taylor, Paul H. J. Donachie, Claire L. Weston, Kathryn J. Robinson, Helen Lucraft, Frank Saran, David W. Ellison, James Ironside, David A. Walker, Barry L. Pizer, Children's Canc Leukaemia Grp CCLG

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Background and purpose: To evaluate the impact of radiotherapy (RT) parameters on outcome in the SIOP/UKCCSG study of pre-RT chemotherapy for Supratentorial Primitive Neuro-ectodermal Tumours.

Methods and materials: Sixty-two patients aged 2.9-16.6 (median 6.4 years) were eligible. Forty-eight (77%) had non-pineal sites and 14 (23%) had pineal sites. Eleven were randomized to RT alone (6) and five to pre-RT Vincristine, Etoposide, Carboplatin and Cyclophosphamide. Fifty-one were not randomized, 15 receiving RT alone and 36 receiving pre-RT chemotherapy. Craniospinal RT (CSRT) 35 Gy/21 fractions were followed by 20 Gy/12 fractions to primary tumour.

Results: Mean CSRT dose was 34.7 Gy and mean total primary dose was 53.4 Gy for those who received radiotherapy. Of 30 relapses, 18 (60%) were local only and 5 (16.7%) were combined local and leptomeningeal. There was no significant impact on Overall Survival (OS) or Event-Free Survival (EFS) of surgery-RT interval for patients treated by pre-RT chemotherapy or RT alone, or duration of RT (completing within 50 days). Planning films were received for 42/54 (77.8%) patients. Fourteen (33%) had one or more targeting deviations (10 cribriform fossa, 11 base of skull). There was a statistically significant increase in the risk of recurrence for patients with cribriform fossa targeting deviations (p = 0.033), but not for patients with base of skull targeting deviations (p = 0.242). There was no statistically significant difference in OS (p = 0.0598) OF EFS (p = 0.0880) for patients who had one or more targeting deviations compared to those who had none.

Conclusions: This study has not demonstrated a statistically significant impact of radiotherapy duration or targeting deviations on OS or EFS, possibly due to small patient numbers. However, multi-institutional SPNET trials should incorporate quality assurance programs including analysis of relapse pattern in relation to primary target Volume coverage. (C) 2009 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 92 (2009) 83-88

Original languageEnglish
Pages (from-to)83-88
Number of pages6
JournalRadiotherapy and Oncology
Issue number1
Publication statusPublished - Jul 2009

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