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Scientific article
Review
Open access
English

RapidArc, intensity modulated photon and proton techniques for recurrent prostate cancer in previously irradiated patients: a treatment planning comparison study

Published inRadiation oncology, vol. 4, 34
Publication date2009
Abstract

BACKGROUND: A study was performed comparing volumetric modulated arcs (RA) and intensity modulation (with photons, IMRT, or protons, IMPT) radiation therapy (RT) for patients with recurrent prostate cancer after RT. METHODS: Plans for RA, IMRT and IMPT were optimized for 7 patients. Prescribed dose was 56 Gy in 14 fractions. The recurrent gross tumor volume (GTV) was defined on 18F-fluorocholine PET/CT scans. Plans aimed to cover at least 95% of the planning target volume with a dose > 50.4 Gy. A maximum dose (DMax) of 61.6 Gy was allowed to 5% of the GTV. For the urethra, DMax was constrained to 37 Gy. Rectal DMedian was < 17 Gy. Results were analyzed using Dose-Volume Histogram and conformity index (CI90) parameters. RESULTS: Tumor coverage (GTV and PTV) was improved with RA (V95% 92.6 +/- 7.9 and 83.7 +/- 3.3%), when compared to IMRT (V95% 88.6 +/- 10.8 and 77.2 +/- 2.2%). The corresponding values for IMPT were intermediate for the GTV (V95% 88.9 +/- 10.5%) and better for the PTV (V95%85.6 +/- 5.0%). The percentages of rectal and urethral volumes receiving intermediate doses (35 Gy) were significantly decreased with RA (5.1 +/- 3.0 and 38.0 +/- 25.3%) and IMPT (3.9 +/- 2.7 and 25.1 +/- 21.1%), when compared to IMRT (9.8 +/- 5.3 and 60.7 +/- 41.7%). CI90 was 1.3 +/- 0.1 for photons and 1.6 +/- 0.2 for protons. Integral Dose was 1.1 +/- 0.5 Gy*cm3 *105 for IMPT and about a factor three higher for all photon's techniques. CONCLUSION: RA and IMPT showed improvements in conformal avoidance relative to fixed beam IMRT for 7 patients with recurrent prostate cancer. IMPT showed further sparing of organs at risk.

Keywords
  • Aged
  • Aged, 80 and over
  • Dose-Response Relationship, Radiation
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local/*radiotherapy
  • Photons/*therapeutic use
  • Prostatic Neoplasms/*radiotherapy
  • Protons/*therapeutic use
  • Radiotherapy Planning, Computer-Assisted/*methods
  • Radiotherapy, Intensity-Modulated/*methods
Citation (ISO format)
WEBER, Damien et al. RapidArc, intensity modulated photon and proton techniques for recurrent prostate cancer in previously irradiated patients: a treatment planning comparison study. In: Radiation oncology, 2009, vol. 4, p. 34. doi: 10.1186/1748-717X-4-34
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ISSN of the journal1748-717X
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