Risk of Secondary Malignant Neoplasms From Proton Therapy and Intensity-Modulated X-Ray Therapy for Early-Stage Prostate Cancer

Journal Article · Mon Jun 01 04:00:00 EDT 2009 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2009.01.001· OSTI ID:21276845

Fontenot, Jonas D ^[1]; Lee, Andrew K ^[2]

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1. Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
2. Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

Purpose: To assess the risk of a secondary malignant neoplasm (SMN) from proton therapy relative to intensity-modulated radiation therapy (IMRT) using X-rays, taking into account contributions from both primary and secondary sources of radiation, for prostate cancer. Methods and Materials: A proton therapy plan and a 6-MV IMRT plan were constructed for 3 patients with early-stage adenocarcinoma of the prostate. Doses from the primary fields delivered to organs at risk of developing an SMN were determined from treatment plans. Secondary doses from the proton therapy and IMRT were determined from Monte Carlo simulations and available measured data, respectively. The risk of an SMN was estimated from primary and secondary doses on an organ-by-organ basis by use of risk models from the Committee on the Biological Effects of Ionizing Radiation. Results: Proton therapy reduced the risk of an SMN by 26% to 39% compared with IMRT. The risk of an SMN for both modalities was greatest in the in-field organs. However, the risks from the in-field organs were considerably lower with the proton therapy plan than with the IMRT plan. This reduction was attributed to the substantial sparing of the rectum and bladder from exposure to the therapeutic beam by the proton therapy plan. Conclusions: When considering exposure to primary and secondary radiation, proton therapy can reduce the risk of an SMN in prostate patients compared with contemporary IMRT.

• OSTI ID: 21276845
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 2 Vol. 74; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BLADDER
CARCINOMAS
COMPUTERIZED SIMULATION
MONTE CARLO METHOD
PATIENTS
PROSTATE
PROTONS
RADIATION DOSES
RADIOTHERAPY
RECTUM
X RADIATION