gms | German Medical Science

27. Deutscher Krebskongress

Deutsche Krebsgesellschaft e. V.

22. - 26.03.2006, Berlin

Clicinal results and results of quality assurance of intraoperative radiotherapy (IORT) in 72 brain tumor patients: Implications of a "learning curve"

Meeting Abstract

  • corresponding author presenting/speaker Patrick Schüller - Strahlentherapie, Universitätsklinikum Münster, Deutschland
  • Stefan Palkovic - Neurochirurgie, Universitätsklinikum Münster
  • Jörg Schröder - Neurochirurgie, Universitätsklinikum Münster
  • Andreas Schuck - Strahlentherapie, Universitätsklinikum Münster
  • Oliver Micke - Strahlentherapie, Universitätsklinikum Münster
  • Hansdetlev Wassmann - Neurochirurgie, Universitätsklinikum Münster
  • Normann Willich - Strahlentherapie, Universitätsklinikum Münster

27. Deutscher Krebskongress. Berlin, 22.-26.03.2006. Düsseldorf, Köln: German Medical Science; 2006. DocPO279

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dkk2006/06dkk389.shtml

Veröffentlicht: 20. März 2006

© 2006 Schüller et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Introduction: Even after resection and radiotherapy, malignant gliomas still have a bad prognosis. Many new treatment methods have been tried with little success. We report on our experience with IORT.

Material and methods: From 9/1992 to 12/2004, 72 pts. with malignant gliomas were treated with IORT. All living patients were followed up for at least 52 months. 26/71 pts. had grade III gliomas, 46/71 pts. had glioblastomas (GBM). 53/72 primarily treated pts. received 20 Gy IORT + 60 Gy external RT, 19/72 pts. with recurrences received 20-25 Gy IORT alone. The beam angle was chosen using neuronavigation. To keep this angle fixed during transport, we constructed a special ‘beam direction indicator’ (BDI). Gantry and couch angles were adjusted to the BDI using a central beam laser. The electron energy was chosen so that the 90% isodose surrounded the tumor bed by 1 cm. In the last 8 patients, the beam parameters were calculated from the neuronavigation image by a coordinate transformation and entered into the treatment planning system, enabling a dose reconstruction. PTV coverage and dose at organs were assessed by quality parameters such as D90, D100, and V90.

Results: The complication rates were 1.5% for wound infections and 4.5% for bleeding. For grade III gliomas, the median specific survival time amounted to 15.3 months, that of GBM was 12.2 months. The 2-year survival rates amounted to 28.0% (gliomas III) and 6.0% (GBM) (p=0.005). Total vs. subtotal resection: p=0.01. Volume and primary/recurrence were not significant. A comparison to a conventionally treated patient group did not show a significant survival difference. Recurrences and glioblastoma patients showed better results than the control. Initial symptoms improved in 59% (hemiparesis), 50% (aphasia), 50% (hemianopsia), and 60% (convulsions). The evaluation of the target volume coverage showed a characteristic "learning curve" with 2 early pts. who received a significant underdosage because of low electron energy.

Conclusion: IORT was shown to be feasible. In most cases, symptoms could be improved. Survival rates were improved for recurrences and glioblastomas. The dose reconstruction method developed by us allows the calculation of a 3-D dose distribution for IORT and enables postoperative quality control. The learning curve indicates that quality assurance can improve results by facilitating the correct choice of electron energy.