PURPOSE: To model the possible interaction between cytotoxic chemotherapy and the radiation dose distribution with respect to the risk of @entity1207 . METHODS AND MATERIALS: A total of 18 non-small-cell @entity2 @entity1 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 @entity1207 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 @entity1207 than the 3D-CRT plan. However, when the chemotherapy equivalent radiation dose exceeds a certain threshold, the @entity1207 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.

Intensity-modulated radiotherapy might increase pneumonitis risk relative to three-dimensional conformal radiotherapy in XXXX receiving combined chemotherapy and radiotherapy: a modeling study of dose dumping.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity1207 :: ('MESH:D017564', 'Disease') :: ['radiation pneumonitis'] @entity2 :: ('MESH:D008175', 'Disease') :: ['lung cancer']
@entity1 :: (9606,Species) :: ['patients']
