International Journal of Radiation Oncology, Biology, Physics

PURPOSE: The goal of our study was to characterize the dynamics of intracellular oxygen during application of radiation at CONV and FLASH dose rates and obtain evidence for or against the oxygen depletion hypothesis as a mechanism of the FLASH effect. METHODS AND MATERIALS: The measurements were performed by the phosphorescence quenching method using probe Oxyphor PtG4, which was delivered into the cellular cytosol by electroporation. RESULTS: (1) Intracellular radiochemical oxygen depletion (ROD) g-value for dose rate of 100 Gy/s in the normoxic range was found to be 0...

PURPOSE: PSMA PET/CT scan is the standard imaging procedure for biochemical recurrent prostate cancer post-prostatectomy due to its high detection rate at low serum PSA levels. However, existing guidelines for clinical target volume (CTV) in prostate bed salvage external beam radiation therapy (sEBRT) are primarily based on experience-based clinical consensus and have been validated using conventional imaging modalities. Therefore, this study aimed to optimize CTV definition in sEBRT by utilizing PSMA PET/CT-detected local recurrences (LRs)...

PURPOSE: The FLAME trial (NCT01168479) showed that isotoxic focal boosting to the intraprostatic lesion(s) in patients with intermediate- and high-risk prostate cancer improves 5-year disease-free survival (DFS). Although the near-minimum dose to the gross tumor volume (D98%) was associated with improved outcomes, a closer look suggested that this might not be the same for all patients. Therefore, we investigated whether risk factors that are associated with a benefit of focal boosting can be identified...

PURPOSE: Preoperative radiosurgery (SRS) is a feasible alternative to postoperative SRS for resected brain metastases (BM). Most reported studies of preoperative SRS utilized single fraction SRS (SF-SRS). The goal of this study was to compare outcomes and toxicity of preoperative SF-SRS with multifraction (3-5 fractions) SRS (MF-SRS) in a large international multicenter cohort (XXX). METHODS AND MATERIALS: Patients with BM from solid cancers, of which at least 1 lesion was treated with preoperative SRS followed by planned resection were included from 8 institutions...

PURPOSE: Despite improvement in systemic therapy, patients with pancreatic ductal adenocarcinoma (PDAC) frequently experience local recurrence. We sought to determine the safety of hypofractionated proton beam radiotherapy (PBT) during adjuvant chemotherapy. METHODS AND PATIENTS: Nine patients were enrolled in a single-institution phase I trial (NCTXXXXXXXX) between 2019 and 2022. Patients had PDAC of the pancreatic head and underwent R0 or R1 resection and adjuvant modified FOLFIRINOX (mFFX) chemotherapy...

PURPOSE: This study aimed to enhance tumor control and abscopal effects by applying diverse stereotactic ablative body radiation (SABR) schedules. METHODS AND MATERIALS: FSaII, CT-26, and 4T1 cells were used for tumor growth delay and lung metastases analysis after one- or five-day interval radiotherapy (RT) with 40, 20, and 20 Gy, respectively. Immunodeficient BALB/c-nude, immunocompetent C3H, and BALB/c mouse models were used. For immune monitoring, FSaII tumors were analyzed using flow cytometry, immunofluorescence staining, and qRT-PCR...

PURPOSE: In the randomized, single-center, PKUFH phase III trial, dose-intensified (72 Gy) radiation therapy was compared with conventional (66 Gy) radiation therapy. In a previous study, we found no significant difference in biochemical progression-free survival (bPFS) between the two cohorts at 4 years. In the current analysis, we provide 7-year outcomes. MATERIALS AND METHODS: Patients with stage pT3-4, positive surgical margins, or prostate-specific antigen increase ≥0...

BACKGROUND: Chemotherapy (CHT) or radiation therapy (RT) are first line treatments for clinical stage II testicular seminoma (CS-II). Historically, clinical stage I (CS-I) seminoma was also treated with CHT or RT, but in the past two decades practice has shifted towards active surveillance for CS-Iwith RT or CHT reserved for patients with progression to CS-II. Limited data exist on contemporary RT techniques and patient stratification, i.e. de novo (CS-II at orchiectomy) vs. relapsed (CS-II diagnosed during surveillance after orchiectomy for CS I)...

INTRODUCTION: Thoracic radiotherapy (RT) for non-small cell lung cancers (NSCLCs) may overcome resistance to tyrosine kinase inhibitors (TKIs). However, the risk of severe treatment-related pneumonitis (TRP) is a major concern, and the results of the combined treatment remain controversial. Therefore, we aimed to systematically review existing publications and provide a meta-analysis of TRP from a combined therapy of thoracic RT and TKIs. METHODS: A systematic literature review was performed using the PubMed-MEDLINE and Embase databases to identify eligible publications...

PURPOSE: Stereotactic radiosurgery (SRS) is the current standard of care in patients with brain metastases and controlled extracranial disease. Radiation necrosis (RN) is the dose-limiting side effect of SRS, but the dose constraints especially for fractionated SRS remain poorly defined. We assessed the risk of RN after 3-fraction SRS with a goal to identify specific dose-volume constraints associated with grade 3 or higher RN (G3RN). METHODS AND MATERIALS: A single-institutional retrospective review of patients treated with 3-fraction SRS was performed...

PURPOSE: The American Association of Physicists in Medicine (AAPM) Radiation Oncology Medical Physics Education Subcommittee (ROMPES) has updated the radiation oncology physics core curriculum for medical residents in the radiation oncology specialty. METHODS AND MATERIALS: Thirteen physicists from the USA and Canada involved in Radiation Oncology resident education were recruited to ROMPES. The group included PhD and MS physicists with a range of clinical and/or academic roles...

PURPOSE: Dose heterogeneity within a tumor target is likely responsible for the biological effects and local tumor control from spatially fractionated radiation therapy (SFRT). This study used a commercially available GRID collimator to assess the inter-plan variability of heterogeneity dose metrics in patients with various bulky tumor sizes and depths. METHODS AND MATERIALS: The three-dimensional heterogeneity metrics of 14 bulky tumors, ranging from 155 to 2161 cm3 in volume, 6 to 23 cm in equivalent diameter, and 3 to 13 cm in depth, and treated with GRID collimator based SFRT were studied...

PURPOSE: To compare clinical outcomes of intensity modulated radiation therapy (IMRT) alone vs IMRT+ brachytherapy (BT) in patients with T1-T2N0M0 oropharyngeal squamous cell cancers (OPSCC). METHODS AND MATERIALS: This open-label randomized controlled trial was conducted at Tata Memorial Hospital, Mumbai, India. Patients with stage I and II OPSCC were considered for IMRT to a dose of 50Gy/25#/5 weeks in phase I followed by randomization (1:1) to further treatment with IMRT (20Gy/10#/2 weeks) or BT (192 Ir high dose rate - 21Gy/7fractions/2 fractions per day)...

PURPOSE: Radiation (RT) refusal is known to have deleterious effects on survival for multiple cancer types. Factors associated with RT refusal by patients with gynecologic malignancies have not been well described. The study aimed to examine factors associated with and the survival impact of documented RT refusal among patients with gynecologic cancers. METHODS AND MATERIALS: This study analyzed data from the National Cancer Database (NCDB) of patients with gynecologic cancers diagnosed between 2004 and 2020...

BACKGROUND: Spine SBRT requires high positioning accuracy and a stable patient to maximize target coverage and reduce excessive irradiation to organs at risk (OARs). Positional verification during spine SBRT delivery helps to ensure accurate positioning for all patients. We report our experience with non-invasive 3-dimensional (3D) target position monitoring during volumetric modulated arc therapy (VMAT) of spine metastases, in non-immobilized patients positioned using only a thin mattress and simple arm and knee supports...

INTRODUCTION: Lymphocytes play an important role in anti-tumor immunity, however, they are also especially vulnerable to depletion during chemoradiotherapy (CRT). The purpose of this study was to compare the incidence of grade 4 lymphopenia (G4L) between proton beam therapy (PBT) and intensity-modulated photon radiotherapy (IMRT) in esophageal cancer patients treated with CRT in a completed randomized trial and to ascertain patient heterogeneity to G4L risk based on treatment and established prognostic factors...

INTRODUCTION: Reirradiation (reRT) with proton beam therapy (PBT) may offer a chance of cure while minimizing toxicity for patients with isolated intrathoracic recurrences of non-small cell lung cancer (NSCLC). However, distant failure remains common, necessitating strategies to integrate more effective systemic therapy. METHODS: This was a phase II, single-arm trial (NCT03087760) of consolidation pembrolizumab after PBT reRT for locoregional recurrences of NSCLC...

The optimal motion management strategy for patients receiving stereotactic arrhythmia radioablation (STAR) for the treatment of ventricular tachycardia (VT) is not fully known. We developed a framework using a digital phantom to simulate cardiorespiratory motion in combination with different motion management strategies to gain insight into the impact of cardiorespiratory motion on STAR. The 4D XCAT phantom was expanded with the 17-segment left ventricular (LV) model which allowed placement of STAR targets in standardized ventricular regions...

PURPOSE: Radiotherapy is part of the standard treatment regimen for non-small cell lung cancer (NSCLC). While radiotherapy is an effective tool to manage NSCLC, it can be associated with significant dose-limiting toxicities. These toxicities can lead to treatment interruption or early termination, worsening clinical outcomes, in addition to reductions in patient quality of life. Based on preclinical efficacy for radioprotection of normal tissues, we evaluated the clinical utility of BIO 300 Oral Suspension (BIO 300; synthetic genistein nanosuspension) in patients with NSCLC...

PURPOSE: Clinical evidence is limited regarding palliative radiotherapy for relieving pancreatic cancer-related pain. We prospectively investigated pain response following short-course palliative radiotherapy in patients with moderate-to-severe pancreatic cancer-related pain. METHODS: In this prospective phase II single center non-randomized trial, 30 patients with moderate-to-severe pain (5-10, on a 0-10 scale) of pancreatic cancer refractory to pain medication, were treated with a short-course palliative radiotherapy; 24 Gy in three weekly fractions (2015-2018)...