title: Exploring the feasibility of dose escalation positron emission tomography-positive disease with intensity-modulated radiation therapy and the effects on normal tissue structures for thoracic malignancies.
abstract: The pattern of failure is one of the major causes of mortality among thoracic patients. Studies have shown a correlation between local control and dose. Intensity-modulated radiation therapy (IMRT) has resulted in conformal dose distributions while limiting dose to normal tissue. However, thoracic malignancies treated with IMRT to highly conformal doses up to 70 Gy still have been found to fail. Thus, the need for dose escalation through simultaneous integrated boost (SIB) may prove effective in minimizing reoccurrences. For our study, 28 thoracic IMRT plans were reoptimized via dose escalation to the gross tumor volume (GTV) and planning target volume (PTV) of 79.2 Gy and 68.4 Gy, respectively. Reoccurrences in surrounding regions of microscopic disease are rare therefore, dose-escalating regional nodes (outside GTV) were not included. Hence, the need to edit GTV margins was acceptable for our retrospective study. A median dose escalation of approximately 15 Gy (64.8-79.2 Gy) via IMRT using SIB was deemed achievable with minimal percent differences received by critical structures compared with the original treatment plan. The target's mean doses were significantly increased based on p-value analysis, while the normal tissue structures were not significantly changed.
authors.affiliation: The University of Texas M D Anderson Cancer Center School of Health Professions, Medical Dosimetry Program, Houston, TX, USA. lehendrickt@yahoo.com
authors.forename: Lehendrick M
authors.initials: LM
authors.lastname: Turner
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Howard
authors.forename: Pouya
authors.initials: P
authors.lastname: Dehghanpour
authors.forename: Renée D
authors.initials: RD
authors.lastname: Barrett
authors.forename: Neal
authors.initials: N
authors.lastname: Rebueno
authors.forename: Matthew
authors.initials: M
authors.lastname: Palmer
authors.forename: Sastry
authors.initials: S
authors.lastname: Vedam
authors.forename: Ann
authors.initials: A
authors.lastname: Klopp
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
authors.forename: James W
authors.initials: JW
authors.lastname: Welsh
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D049268:Positron-Emission Tomography; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome