Medulloblastoma in childhood: Impact of radiation technique upon the outcome of treatment.
BACKGROUND
Medulloblastoma is an infratentorial primitive neuroectodermal tumour, diagnosed in paediatric population. The radiotherapy is an essential method of treatment for these tumours. The impact of technical quality of radiation therapy on survival was recently considered. In this study treatment-related variables are analysed with a special focus on radiotherapy technical factors.


METHODS
The population of 158 children with a diagnosis of medulloblastoma had been undergoing postoperative radiotherapy at MCMCC in Warsaw in the period 1983-1997. The medical data of these patients were analysed. Simulation films of the whole-brain irradiation fields were retrospectively reviewed at 112 patients. The distance from the field margin to the cribriform plate and to the floor of the temporal fossa was assessed and correlated with supratentorial relapse.


RESULTS
Five-year overall survival (OS) and 5-year disease free survival (DFS) were 46% and 40%, respectively. In multivariate analysis gender (P = 0.008), neurological status before radiotherapy (P = 0.029), M-stage (P < 0.001) and sequence of craniospinal irradiation (P = 0.019) were significant prognostic factors for OS. For DFS significant factors were M-stage (P < 0.001) and neurological status (P < 0.001). The cranial fields were not fully correctly covered at 43% patients. The field incorrectness was correlated with isolated supratentorial failure (P = 0.049).


CONCLUSIONS
Our results are similar to those published in literature. M0-stage was the most powerful favourable prognostic factor. Male gender and neurological status before radiation treatment were associated with poor survival. Also protracted radiotherapy and quality of radiation technique may have an impact on the outcome.
Chojnacka
Marzanna
M
1st Department of Radiation Oncology, The Maria Skłodowska-Curie Memorial Cancer Centre, and Institute of Oncology, Warsaw, Poland. marzanna.ch1@wp.pl
Skowrońska-Gardas
Anna
A
D000293:Adolescent; D002528:Cerebellar Neoplasms / Q000175:diagnosis / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D016371:Cranial Irradiation; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008527:Medulloblastoma / Q000175:diagnosis / Q000532:radiotherapy*; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009367:Neoplasm Staging; D009483:Neuropsychological Tests; D011044:Poland; D011379:Prognosis; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies; D017678:Sex Distribution; D013120:Spinal Cord Neoplasms / Q000175:diagnosis / Q000532:radiotherapy*; D015173:Supratentorial Neoplasms / Q000473:pathology; D015996:Survival Rate; D016896:Treatment Outcome