International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2019
Long-Term Pulmonary Outcomes of a Feasibility Study of Inverse-Planned, Multibeam Intensity Modulated Radiation Therapy in Node-Positive Breast Cancer Patients Receiving Regional Nodal Irradiation.
Multibeam intensity modulated radiation therapy (IMRT) enhances the therapeutic index by increasing the dosimetric coverage of the targeted tumor tissues while minimizing volumes of adjacent organs receiving high doses of RT. The tradeoff is that a greater volume of lung is exposed to low doses of RT, raising concern about the risk of radiation pneumonitis (RP). ⋯ Multibeam IMRT in patients with breast cancer receiving regional nodal irradiation was dosimetrically feasible, based on early treatment planning criteria. Despite the large volume of lung receiving low-dose RT, the incidence of grade 3 RP was remarkably low, justifying inverse-planned IMRT as a treatment modality for patients with high-risk breast cancer in whom conventional RT techniques prove inadequate.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2019
Randomized Controlled Trial Multicenter Study Comparative StudyLong-term Follow-up on NRG Oncology RTOG 0915 (NCCTG N0927): A Randomized Phase 2 Study Comparing 2 Stereotactic Body Radiation Therapy Schedules for Medically Inoperable Patients With Stage I Peripheral Non-Small Cell Lung Cancer.
To present long-term results of RTOG 0915/NCCTG N0927, a randomized lung stereotactic body radiation therapy trial of 34 Gy in 1 fraction versus 48 Gy in 4 fractions. ⋯ No excess in late-appearing toxicity was seen in either arm. Primary tumor control rates at 5 years were similar by arm. A median survival time of 4 years for each arm suggests similar efficacy, pending any larger studies appropriately powered to detect survival differences.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2019
Lens Dose-Response Prediction Modeling and Cataract Incidence in Patients With Retinoblastoma After Lens-Sparing or Whole-Eye Radiation Therapy.
We retrospectively assessed the incidence of cataracts in patients with retinoblastoma (Rb) treated with either lens-sparing radiation therapy (LSRT) or whole-eye radiation therapy (WERT). A secondary aim of this study was to model the dose-response risk of cataract. ⋯ We report the first clinical data demonstrating significantly improved EFS in patients with Rb treated with LSRT. Through lens dose-response modeling, we validate a mean lens dose threshold of 7 Gy to keep cataract risk below 25%. Although RT is used less often for Rb owing to advances in chemotherapy delivery options, these findings are relevant for refining lens dose constraints, particularly in children who have received radiation dose near the orbit.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2019
Randomized Controlled TrialModerate Hypofractionation in Intermediate- and High-Risk, Localized Prostate Cancer: Health-Related Quality of Life From the Randomized, Phase 3 HYPRO Trial.
The phase 3 Hypofractionated Irradiation for Prostate Cancer trial compared hypofractionated radiation therapy with conventionally fractionated radiation therapy in patients with localized prostate cancer. Similar 5-year relapse-free survival rates were achieved in both groups, but noninferiority of hypofractionation was not confirmed for genitourinary and gastrointestinal toxicity. Here, we present the secondary trial endpoint on patient-reported quality of life. ⋯ Noninferiority of the hypofractionated treatment was not demonstrated for genitourinary and gastrointestinal quality of life, and therefore we cannot rule out that relevant differences may exist between both treatments. Noninferiority of hypofractionation was demonstrated for symptoms related to androgen deprivation therapy, sexual activity, and sexual function.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2019
Introducing Proton Track-End Objectives in Intensity Modulated Proton Therapy Optimization to Reduce Linear Energy Transfer and Relative Biological Effectiveness in Critical Structures.
We propose the use of proton track-end objectives in intensity modulated proton therapy (IMPT) optimization to reduce the linear energy transfer (LET) and the relative biological effectiveness (RBE) in critical structures. ⋯ Proton track-end objectives allow for LETd reductions in critical structures without compromising the physical target dose. This approach permits the lowering of DRBE and NTCP in critical structures, independent of the variable RBE model used, and it could be introduced in clinical practice without changing current protocols based on the constant RBE of 1.1.