Carbon Ion irradiation in the treatment of grossly incomplete or unresectable malignant peripheral nerve sheaths tumors: acute toxicity and preliminary outcome.
BACKGROUND
To report our early experience with carbon ion irradiation in the treatment of gross residual or unresectable malignant peripheral nerve sheath tumors (MPNST).


METHODS
We retrospectively analysed 11 patients (pts) with MPNST, who have been treated with carbon ion irradiation (C12) at our institution between 2010 and 2013. All pts had measurable gross disease at the initiation of radiation treatment. Median age was 47 years (29-79). Tumors were mainly located in the pelvic/sacral (5 pts) and sinunasal/orbital region (5 pts). 5 pts presented already in recurrent situation, 3 pts had been previously irradiated, and in 3 pts MPNST were neurofibromatosis type 1 (NF1) associated. Median cumulative dose was 60 GyE. Treatment was carried out either as a combination of IMRT plus C12 boost (4 pts) or C12 only (7 pts).


RESULTS
Median follow-up was 17 months (3-31 months). We observed 3 local progressions, translating into estimated 1- and 2-year local control rates of 65%. One patient developed distant failure, resulting in estimated 1- and 2-year PFS rates of 56%. Two patients have died, therefore the estimated 1- and 2-year OS rates are 75%. Acute radiation related toxicities were generally mild, no grade 3 side effects were observed. Severe late toxicity (grade 3) was scored in 2 patients (trismus, wound healing delays).


CONCLUSIONS
Carbon ion irradiation yields very promising short term local control and overall survival rates with low morbidity in patients suffering from gross residual or unresectable malignant peripheral nerve sheath tumors and should be further investigated in a prospective trial.
Department of Radiation Oncology, University of Heidelberg, INF 400, 69120, Heidelberg, Germany. alexdjensen@gmx.de.
Alexandra D
AD
Jensen
Department of Radiation Oncology, University of Heidelberg, INF 400, 69120, Heidelberg, Germany. Matthias.Uhl@med.uni-heidelberg.de.
Matthias
M
Uhl
Department of Medical Physics, Heidelberg Ion Beam Therapy Centre (HIT), Heidelberg, Germany. Naved.Chaudhri@med.uni-heidelberg.de.
Naved
N
Chaudhri
Department of Radiation Oncology, University of Heidelberg, INF 400, 69120, Heidelberg, Germany. Klaus.Herfarth@med.uni-heidelberg.de.
Klaus K
KK
Herfarth
Department of Radiation Oncology, University of Heidelberg, INF 400, 69120, Heidelberg, Germany. Juergen.Debus@med.uni-heidelberg.de.|Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany. Juergen.Debus@med.uni-heidelberg.de.
Juergen
J
Debus
Department of Radiation Oncology, University of Heidelberg, INF 400, 69120, Heidelberg, Germany. Falk.Roeder@med.uni-muenchen.de.|Department of Molecular and Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany. Falk.Roeder@med.uni-muenchen.de.
Falk
F
Roeder
D000328:Adult; D000368:Aged; D005260:Female; D063193:Heavy Ion Radiotherapy / Q000009:adverse effects* / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009442:Neurilemmoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011379:Prognosis; D011832:Radiation Injuries / Q000209:etiology* / Q000401:mortality; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D012189:Retrospective Studies; D015996:Survival Rate