International journal of radiation oncology, biology, physics
-
Int. J. Radiat. Oncol. Biol. Phys. · Mar 2017
Randomized Controlled TrialEffect of Long-Term Hormonal Therapy (vs Short-Term Hormonal Therapy): A Secondary Analysis of Intermediate-Risk Prostate Cancer Patients Treated on NRG Oncology RTOG 9202.
NRG Oncology RTOG 9202 was a randomized trial testing long-term adjuvant androgen deprivation (LTAD) versus initial androgen deprivation only (STAD) with external beam radiation therapy (RT) in mostly high-risk and some intermediate-risk prostate cancer patients. RTOG 9408 found an overall survival (OS) advantage in patients with cT1b-T2b disease and prostate-specific antigen (PSA) <20 ng/mL, with benefit observed mostly among intermediate-risk patients. It was still unknown whether intermediate-risk patients would experience an additional survival benefit with LTAD; thus, we performed a secondary analysis to explore whether LTAD had any incremental benefit beyond STAD among the intermediate-risk subset of RTOG 9202. The study endpoints were OS, disease-specific survival (DSS), and PSA failure (PSAF). ⋯ LTAD did not confer a benefit in terms of OS, DSS, or PSAF rates in the intermediate-risk subset in this study. Whereas the subset was relatively small, treatment assignment was randomly applied, and a trend in favor of LTAD would have been of interest. Given the small number of disease-specific deaths observed and lack of benefit with respect to our endpoints, this secondary analysis does not suggest that exploration of longer hormonal therapy is worth testing in the intermediate-risk prostate cancer subset.
-
Int. J. Radiat. Oncol. Biol. Phys. · Mar 2017
Association of Radiomics and Metabolic Tumor Volumes in Radiation Treatment of Glioblastoma Multiforme.
To build a framework for investigation of the associations between imaging, clinical target volumes (CTVs), and metabolic tumor volumes (MTVs) features for better understanding of the underlying information in the CTVs and dependencies between these volumes. High-throughput extraction of imaging and metabolomic quantitative features from magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging of glioblastoma multiforme (GBM) results in tens of variables per patient. In radiation therapy of GBM the relevant metabolic tumor volumes (MTVs) are related to aberrant levels of N-acetyl aspartate (NAA) and choline (Cho). The corresponding clinical target volumes (CTVs) for radiation therapy are based on contrast-enhanced T1-weighted (CE-T1w) and T2-weighted (T2w)/fluid-attenuated inversion recovery MRI. ⋯ A framework for investigation of codependencies between MRI and magnetic resonance spectroscopic imaging radiomic features and CTVs/MTVs has been established. The MTV for NAA was found to be closely associated with MRI volumes, whereas very few imaging features were related to MTVCho, indicating that Cho provides additional information to imaging.
-
Int. J. Radiat. Oncol. Biol. Phys. · Feb 2017
Multicenter StudyMulti-institutional Nomogram Predicting Survival Free From Salvage Whole Brain Radiation After Radiosurgery in Patients With Brain Metastases.
Optimal patient selection for stereotactic radiosurgery (SRS) as the initial treatment for brain metastases is complicated and controversial. This study aimed to develop a nomogram that predicts survival without salvage whole brain radiation therapy (WBRT) after upfront SRS. ⋯ Our nomogram can be used at initial evaluation to help select patients best suited for upfront SRS for brain metastases while reducing expense and morbidity in patients who derive minimal or no benefit.
-
Int. J. Radiat. Oncol. Biol. Phys. · Feb 2017
Chemotherapy Response Assessment by FDG-PET-CT in Early-stage Classical Hodgkin Lymphoma: Moving Beyond the Five-Point Deauville Score.
In early-stage classical Hodgkin lymphoma, fluorodeoxyglucose positron emission tomography (PET)-computed tomography (CT) scans are performed routinely after chemotherapy, and the 5-point Deauville score is used to report the disease response. We hypothesized that other PET-CT parameters, considered in combination with Deauville score, would improve risk stratification. ⋯ The relative reduction in tumor size is an independent predictor of outcome. Combined with the Deauville score, it might improve risk stratification and contribute to response-adapted individualization of therapy.
-
Int. J. Radiat. Oncol. Biol. Phys. · Feb 2017
Comparative StudyProton Treatment Techniques for Posterior Fossa Tumors: Consequences for Linear Energy Transfer and Dose-Volume Parameters for the Brainstem and Organs at Risk.
In proton therapy of posterior fossa tumors, at least partial inclusion of the brainstem in the target is necessary because of its proximity to the tumor and required margins. Additionally, the preferred beam geometry results in directing the field distal edge toward this critical structure, raising concerns for brainstem toxicity. Some treatment techniques place the beam's distal edge within the brainstem (dose-sparing techniques), and others avoid elevated linear energy transfer (LET) of the proton field by placing the distal edge beyond it (LET-sparing techniques). Hybrid approaches are also being used. We examine the dosimetric efficacy of these techniques, accounting for LET-dependent and dose-dependent variable relative biologic effectiveness (RBE) distributions. ⋯ Extending the proton range beyond the brainstem to reduce LET results in clinically comparable maximum radiobiologic effective dose to this sensitive structure. However this method significantly increasing the brainstem volume receiving RBE-weighted dose higher than 55 Gy(RBE) with possible consequences based on known dose-volume parameters for increased toxicity.