gms | German Medical Science

48th Meeting of the Particle Therapy Co-Operative Group

Particle Therapy Co-Operative Group (PTCOG)

28.09. - 03.10.2009, Heidelberg

To compare treatment planning results for primary radiotherapy of prostate cancer using proton, 3-dimensional conformal and intensity modulated radiotherapy

Meeting Abstract

  • G. De Meerleer - Department of Radiotherapy and nuclear medicine, Ghent University Hospital, Ghent, Belgium
  • E. Roelofs - Department of Radiation Oncology (MAASTRO), GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
  • M. Engelsman - The Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School (MGH/HMS), Boston, USA
  • L. Persoon - Department of Radiation Oncology (MAASTRO), GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
  • M. Coghe - Department of Radiotherapy and nuclear medicine, Ghent University Hospital, Ghent, Belgium
  • J. van den Boogaard - Department of Radiation Oncology (MAASTRO), GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
  • V. Fonteyne - Department of Radiotherapy and nuclear medicine, Ghent University Hospital, Ghent, Belgium
  • I. Madani - Department of Radiotherapy and nuclear medicine, Ghent University Hospital, Ghent, Belgium
  • W. De Neve - Department of Radiotherapy and nuclear medicine, Ghent University Hospital, Ghent, Belgium
  • M. Scholz - GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
  • J. Debus - Heidelberger Ionenstrahl-Therapie (HIT), Heidelberg, Germany
  • O. Jäkel - Heidelberger Ionenstrahl-Therapie (HIT), Heidelberg, Germany
  • F. Verhaegen - Department of Radiation Oncology (MAASTRO), GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
  • M. Pijls-Johannesma - Department of Radiation Oncology (MAASTRO), GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
  • P. Lambin - Department of Radiation Oncology (MAASTRO), GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands

PTCOG 48. Meeting of the Particle Therapy Co-Operative Group. Heidelberg, 28.09.-03.10.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09ptcog051

DOI: 10.3205/09ptcog051, URN: urn:nbn:de:0183-09ptcog0514

Published: September 24, 2009

© 2009 De Meerleer et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Background: To compare treatment planning results for primary radiotherapy of prostate cancer using proton, 3-dimensional conformal and intensity modulated radiotherapy.

Material and methods: The CT data of 5 consecutive prostate cancer patients were used for the study. For each patient, CTV consisted of prostate and seminal vesicles. PTV was created using an isotropic margin of 4 mm around CTV. The relevant organs at risk (OAR) were rectum, bladder and femoral heads. Delineation of CTV and OAR was performed at the radiotherapy department of UZG. Three different treatment plans were generated for each patient:

1.
A proton plan (P) by MGH, using two passive scattered lateral beams using custom apertures and range compensators with 1 cm smearing. Regarding distal and proximal conformation a range uncertainty of 3.5% on top of the PTV expansion was taken into account.
2.
A 3D-CRT photon plan (CRT) by MAASTRO, using 4 orthogonal 10 MV beams with MLC blocking.
3.
An IMRT photon plan (IMRT) by UZG, using 3 beams (0-116-244°) and 18 MV photons with leaf position optimization for the beam aperture.

All plans were rescaled to a maximal rectal dose of 76 Gy (hard constraint). For CTV and PTV, the mean and median dose (Dmean, Dmed) and the dose received by 98% and 2% of the volume (D98, D2) were used for comparison. D98 and D2 are surrogates for minimal and maximal dose respectively. For rectum, the following parameters were used: Dmean, and the rectal volume that receives 40 (V40), 50 (V50), 60 (V60), 65 (V65) and 70 Gy (V70). Concerning bladder and femoral heads, Dmean and D2 were studied. Statistics were done using the Friedman and Wilcoxon tests, the latter for pairwise comparison.

Results: The results are presented in Table 1 [Tab. 1] and Figure 1 [Fig. 1]. For the CTV and PTV, Dmed, Dmean and D2, showed significantly higher results for P compared to CRT (p<0.05). The differences with IMRT did not reach significance, except for D98 of PTV.

Concerning rectum, V40, V60, V65 and Dmean were significantly lower in P than in IMRT and CRT (p<0.05). For Dmean, the difference was >10 Gy. On the other hand, V70 was significantly lower in IMRT and CRT compared to P (p<0.05). Mean bladder dose was significantly lower in P (p<0.05 for both CRT and IMRT; difference >7 Gy). Mean femoral head dose was significantly lower in IMRT compared to CRT and P (p<0.05; difference >7 Gy).

Conclusion: Concerning prostate cancer treatment planning, there is a therapeutic benefit of proton plans when compared to photon plans. This benefit is explained by combining higher doses to CTV/PTV with lower doses to rectum and bladder.