Inter-clinician variability in making dosimetric decisions in pediatric treatment: a balance between efficacy and late effects.
OBJECTIVE
To investigate variability of clinical target volume (CTV) delineation and deviations according to doses delivered in normal tissue for abdominal tumor irradiation in children.


METHODS
For a case of nephroblastoma six French pediatric radiation oncologists outlined post-operative CTV, on the same dosimetric CT scan according to the International Society for Pediatric Oncology 2001 protocol. On a reference CTV and organs at risk (OAR), we performed dosimetric planning with the constraints as 25.2 Gy for CTV, V(20 max) to 50% for liver, V(12) <15% for kidney. Data were analyzed with Aquilab software.


RESULTS
Final CTVs showed inter-clinician variability: 44.85-120.78 cm(3). The recommended liver doses were not respected in four cases: V(20) from 74% to 88% of the volume; for kidney, in two cases: V(12) of 17.6% and 25%, respectively. For vertebral bodies, no deviations were noted.


CONCLUSIONS
Variability not only affected CTV delineation but also dose distribution to OAR with different compromises. This practice training demonstrates the hudge lack of data about correlation between dose, volume and risk of late effects in pediatric radiotherapy. We intend to record prospectively the dose/volume histogram of each OAR in a national database in order to characterize late effects occurring in relation to treatment modalities.
Padovani
Laetitia
L
CHU La Timone Marseille, France. laetitia.padovani@ap-hm.fr
Huchet
Aymeri
A
Claude
Line
L
Bernier
Valerie
V
Quetin
Philippe
P
Mahe
Marc
M
Laprie
Anne
A
Kerr
Christine
C
Bondiau
Pierre Yves
PY
Delarue
Arnaud
A
Coze
Carole
C
Gibon
David
D
Barteau
Clarisse
C
Maire
Jean Philippe
JP
Carrie
Christian
C
Muracciole
Xavier
X
D000293:Adolescent; D001842:Bone and Bones / Q000528:radiation effects; D002648:Child; D002675:Child, Preschool; D003657:Decision Making; D005260:Female; D006801:Humans; D007223:Infant; D007668:Kidney / Q000528:radiation effects; D008099:Liver / Q000528:radiation effects; D009369:Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D014057:Tomography, X-Ray Computed