Spot-scanning proton therapy for malignant soft tissue tumors in childhood: First experiences at the Paul Scherrer Institute.
OBJECTIVE
Radiotherapy plays a major role in the treatment strategy of childhood sarcomas. Consequences of treatment are likely to affect the survivor's quality of life significantly. We investigated the feasibility of spot-scanning proton therapy (PT) for soft tissue tumors in childhood.


METHODS
Sixteen children with soft tissue sarcomas were included. Median age at PT was 3.3 years. In 10 children the tumor histology was embryonal rhabdomyosarcoma. All tumors were located in the head or neck, parameningeal, or paraspinal, or pelvic region. In the majority of children, the tumor was initially unresectable (Intergroup Rhabdomyosarcoma Study [IRS] Group III in 75%). In 50% of children the tumors exceeded 5 cm. Fourteen children had chemotherapy before and during PT. Median total dose of radiotherapy was 50 cobalt Gray equivalent (CGE). All 16 children were treated with spot-scanning proton therapy at the Paul Scherrer Institute, and in 3 children the PT was intensity-modulated (IMPT).


RESULTS
After median follow-up of 1.5 years, local control was achieved in 12 children. Four children failed locally, 1 at the border of the radiation field and 3 within the field. All 4 children died of tumor recurrence. All 4 showed unfavorable characteristic either of site or histopathology of the tumor. Acute toxicity was low, with Grade 3 or 4 side effects according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria occurring in the bone marrow only.


CONCLUSIONS
Proton therapy was feasible and well tolerated. Early local control rates are comparable to those being achieved after conventional radiotherapy. For investigations on late effect, longer follow-up is needed.
Timmermann
Beate
B
Division of Radiation Medicine, Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland. beate.timmermann@psi.ch
Schuck
Andreas
A
Niggli
Felix
F
Weiss
Markus
M
Lomax
Antony Jonathan
AJ
Pedroni
Eros
E
Coray
Adolf
A
Jermann
Martin
M
Rutz
Hans Peter
HP
Goitein
Gudrun
G
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005240:Feasibility Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy; D006801:Humans; D007223:Infant; D008297:Male; D008577:Meningeal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy; D061766:Proton Therapy; D011788:Quality of Life; D011832:Radiation Injuries / Q000473:pathology; D018233:Rhabdomyosarcoma, Embryonal / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy; D012509:Sarcoma / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D013125:Spinal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy; D017741:Survivors; D011522:Protons
D011522:Protons