Intensity-Modulated Radiotherapy Might Increase Pneumonitis Risk Relative to Three-Dimensional Conformal Radiotherapy in Patients Receiving Combined Chemotherapy and Radiotherapy: A Modeling Study of Dose Dumping

Journal Article · Fri Jul 01 00:00:00 EDT 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.12.073· OSTI ID:21587577

Vogelius, Ivan S ^[1]; Westerly, David C; Cannon, George M; Mackie, Thomas R; Mehta, Minesh P ^[2]; Sugie, Chikao ^[3]

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1. Department of Oncology, Vejle Sygehus, Vejle (Denmark)
2. Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI (United States)
3. Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya (Japan)

Purpose: To model the possible interaction between cytotoxic chemotherapy and the radiation dose distribution with respect to the risk of radiation pneumonitis. Methods and Materials: A total of 18 non-small-cell lung cancer patients previously treated with helical tomotherapy at the University of Wisconsin were selected for the present modeling study. Three treatment plans were considered: the delivered tomotherapy plans; a three-dimensional conformal radiotherapy (3D-CRT) plan; and a fixed-field intensity-modulated radiotherapy (IMRT) plan. The IMRT and 3D-CRT plans were generated specifically for the present study. The plans were optimized without adjusting for the chemotherapy effect. The effect of chemotherapy was modeled as an independent cell killing process by considering a uniform chemotherapy equivalent radiation dose added to all voxels of the organ at risk. The risk of radiation pneumonitis was estimated for all plans using the Lyman and the critical volume models. Results: For radiotherapy alone, the critical volume model predicts that the two IMRT plans are associated with a lower risk of radiation pneumonitis than the 3D-CRT plan. However, when the chemotherapy equivalent radiation dose exceeds a certain threshold, the radiation pneumonitis risk after IMRT is greater than after 3D-CRT. This threshold dose is in the range estimated from clinical chemoradiotherapy data sets. Conclusions: Cytotoxic chemotherapy might affect the relative merit of competing radiotherapy plans. More work is needed to improve our understanding of the interaction between chemotherapy and the radiation dose distribution in clinical settings.

• OSTI ID: 21587577
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 80, Issue 3; Other Information: DOI: 10.1016/j.ijrobp.2010.12.073; PII: S0360-3016(11)00222-7; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CHEMOTHERAPY
COMBINED THERAPY
COMPUTERIZED TOMOGRAPHY
CT-GUIDED RADIOTHERAPY
HAZARDS
LUNGS
NEOPLASMS
PNEUMONITIS
RADIATION DOSE DISTRIBUTIONS
SIMULATION
THRESHOLD DOSE
BODY
DIAGNOSTIC TECHNIQUES
DISEASES
DOSES
MEDICINE
NUCLEAR MEDICINE
ORGANS
RADIATION DOSES
RADIOLOGY
RADIOTHERAPY
RESPIRATORY SYSTEM
THERAPY
TOMOGRAPHY