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Purpose: The presence of MYC and BCL2 translocations (ie, double-hit lymphoma, DHL) in large B-cell lymphoma (LBCL) is associated with reduced chemosensitivity, but less is known on its impact on radiotherapy (RT) efficacy., Methods and Materials: Patients with LBCL who received their first course of RT for relapsed/refractory disease between 2008 and 2020 were eligible if there was adequate pathologic evaluation to be categorized as DHL versus non-DHL as per the World Health Organization (fifth edition). Separate analyses were conducted by treatment intent. Predictors for response (complete and partial) and local recurrence (LR) were evaluated using Cox regression analysis. LR analysis was restricted to curative-intent patients to ensure adequate follow-up., Results: Three hundred and eighty-three patients (102 DHL, 281 non-DHL, and 44% curative) were treated at 447 sites. Median time from diagnosis to RT was 11.6 months, with 38.7% of patients having primary chemorefractory disease, 37.4% having received >2 lines of systemic therapy, and 24% status post-stem cell transplant. Median biological equivalent dose (alpha/beta: 10) was 28 Gy (range: 3.2-60.0) for palliative and 46.9 Gy (range: 6.4-84.0) for curative-intent patients. With a median follow-up of 41.1 and 41.5 months among curative and palliative patients, respectively, the response was high (81.1% curative, 60.1% palliative). On univariate analysis, DHL pathology was not associated with RT response in either curative or palliative patients. Among curative patients, 2-year LR rate was 38.8%. On multivariable analysis, DHL pathology was associated with a 2 times higher risk of LR (95% CI: 1.05-3.67, P = .03), with a crude LR rate of 42.9% (DHL) versus 28.9% (non-DHL). RT was well tolerated with low rates of grade 3 or higher acute toxicity (1.8% curative, 2.9% palliative)., Conclusions: Relapsed/refractory LBCL remains radioresponsive with a 60%-80% response rate to RT. Although DHL pathology does not appear to influence RT response, its presence is associated with higher rates of LR, suggesting that it may be more radioresistant., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: External beam radiation therapy (EBRT) is a safe and emerging bridging liver-directed therapy (LDT) to liver transplant (LT) for patients with hepatocellular carcinoma (HCC). The prevalence and clinical characteristics of patients receiving EBRT as an LDT for LT have not been evaluated. Our aim was to describe the utilization of EBRT in patients with HCC evaluated for LT in the United States., Methods and Materials: We analyzed United Network for Organ Sharing data from October 2013 to June 2020 and identified patients with HCC who applied for model for end-stage liver disease (MELD) exceptions for LT wait list prioritization. The primary outcome was the period prevalence of EBRT. We examined associations between clinical variables and EBRT and fit survival models with EBRT as a time-varying predictor., Results: We identified 18,543 patients with HCC with MELD exception applications. EBRT was used in 658 patients (3.5%) either alone (1.2%) or combined with other LDT (2.3%). Transarterial chemoembolization was the most used LDT (59.3%), followed by thermal ablation (27.9%) and radioembolization (15.2%). EBRT prevalence rose by an average of 12.2% per year (P = .001). Use of EBRT differed by geographic region, ranging from 2% to 8% (P < .001). EBRT and no EBRT groups had similar initial MELD score, portal vein thrombosis, tumor diameter, number of tumors, bilirubin, and α-fetoprotein (P > .05). Median time-to-transplant from wait list registration for EBRT versus no EBRT groups was 10 months (95% confidence interval, 9.4-10.9) versus 11.9 months (95% confidence interval, 11.7-12.2; P < .001). Evaluated as a time-varying predictor, EBRT increased the risk of LT by 30% (sub-hazard ratio, 1.30; P < .001), while the effect of EBRT on the risk of wait list removal due to clinical deterioration or death (sub-hazard ratio, 1.07; P = .489) was nonsignificant., Conclusions: In the United States, EBRT is rarely used compared with other LDTs and exhibits geographic variation. Low EBRT utilization highlights a gap in the treatment armamentarium for HCC., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: The role of MerTK, a member of the Tyro3-Axl-MerTK family of receptor tyrosine kinase, in the immune response to radiation therapy (RT) is unclear. We investigated immune-mediated tumor control after RT in murine models of colorectal and pancreatic adenocarcinoma using MerTK wild-type and knock-out hosts and whether inhibition of MerTK signaling with warfarin could replicate MerTK knock-out phenotypes., Methods and Materials: Wild-type and MerTK -/- BALB/c mice were grafted in the flanks with CT26 tumors and treated with computed tomography guided RT. The role of macrophages and CD8 T cells in the response to radiation were demonstrated with cell depletion studies. The role of MerTK in priming immune responses after RT alone and with agonist antibodies to the T cell costimulatory molecule OX40 was evaluated in a Panc02-SIY model antigen system. The effect of warfarin therapy on the in-field and abscopal response to RT was demonstrated in murine models of colorectal adenocarcinoma. The association between warfarin and progression-free survival for patients treated with SABR for early-stage non-small cell lung cancer was evaluated in a multi-institutional retrospective study., Results: MerTK -/- hosts had better tumor control after RT compared with wild-type mice in a macrophage and CD8 T cell-dependent manner. MerTK -/- mice showed increased counts of tumor antigen-specific CD8 T cells in the peripheral blood after tumor-directed RT alone and in combination with agonist anti-OX40. Warfarin therapy phenocopied MerTK -/- for single-flank tumors treated with RT and improved abscopal responses for RT combined with anti-CTLA4. Patients on warfarin therapy when treated with SABR for non-small cell lung cancer had higher progression-free survival rates compared with non-warfarin users., Conclusions: MerTK inhibits adaptive immune responses after SABR. Because warfarin inhibits MerTK signaling and phenocopies genetic deletion of MerTK in mice, warfarin therapy may have beneficial effects in combination with SABR and immune therapy in patients with cancer., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: To report the toxicities and outcomes for stereotactic body radiation therapy (SBRT) and accelerated hypofractionated radiation therapy (AHRT) in patients with Child-Pugh (CP) class A, B, or C and albumin-bilirubin (ALBI) score 1, 2, or 3 hepatocellular carcinoma., Methods and Materials: We retrospectively reviewed the data from 146 patients with hepatocellular carcinoma who had undergone SBRT (50 Gy in 5 fractions) or AHRT (45 Gy in 18 fractions). The primary endpoint was liver toxicity, defined as an increase in the CP score of ≥2 within 6 months of radiation therapy. The secondary endpoints of ALBI change, overall survival, and local control were also calculated., Results: The median follow-up was 23 months (range 1-59). Most received SBRT (72%), and 28% received AHRT. Of all 146 patients, 45 (31%) had a CP score elevation of ≥2 within 6 months of radiation therapy (RT) (27 patients [28%] with baseline CP-A/B7 and 18 [35%] with baseline CP-B8/B9/C cirrhosis; P = .45). On multivariate analysis, neither baseline CP nor ALBI score was predictive of toxicity. No patient with a decline in liver functionality of CP ≥2 within 6 months of RT returned to baseline at later time points. Eleven grade 4 toxicities were observed. The mean change in the raw ALBI score at ∼6 months was similar for all baseline ALBI groups. Twenty-two patients underwent orthotopic liver transplantation after RT, 13 of whom had baseline CP-B8/B9/C liver functionality. For all patients, the 1- and 2-year treated-lesion local control was greater for SBRT than for AHRT (2-year 94% vs 65%, P < .0001)., Conclusions: The tolerability of SBRT or AHRT as measured by a CP score decline of ≥2 within 6 months of RT was similar across baseline liver functionality groups. Compared with AHRT, SBRT was associated with superior local control. Because the true tolerability of limited-volume RT for patients with CP-B or CP-C cirrhosis is unknown, prospective trials validating its safety and efficacy are warranted., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To survey image guided radiation therapy (IGRT) practice patterns, as well as IGRT's impact on clinical workflow and planning treatment volumes (PTVs)., Methods and Materials: A sample of 5979 treatment site-specific surveys was e-mailed to the membership of the American Society for Radiation Oncology (ASTRO), with questions pertaining to IGRT modality/frequency, PTV expansions, method of image verification, and perceived utility/value of IGRT. On-line image verification was defined as images obtained and reviewed by the physician before treatment. Off-line image verification was defined as images obtained before treatment and then reviewed by the physician before the next treatment., Results: Of 601 evaluable responses, 95% reported IGRT capabilities other than portal imaging. The majority (92%) used volumetric imaging (cone-beam CT [CBCT] or megavoltage CT), with volumetric imaging being the most commonly used modality for all sites except breast. The majority of respondents obtained daily CBCTs for head and neck intensity modulated radiation therapy (IMRT), lung 3-dimensional conformal radiation therapy or IMRT, anus or pelvis IMRT, prostate IMRT, and prostatic fossa IMRT. For all sites, on-line image verification was most frequently performed during the first few fractions only. No association was seen between IGRT frequency or CBCT utilization and clinical treatment volume to PTV expansions. Of the 208 academic radiation oncologists who reported working with residents, only 41% reported trainee involvement in IGRT verification processes., Conclusion: Consensus guidelines, further evidence-based approaches for PTV margin selection, and greater resident involvement are needed for standardized use of IGRT practices., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: The purpose of this project was to survey radiation oncology chief residents to define their residency experience and readiness for independent practice., Methods and Materials: During the academic years 2013 to 2014 and 2014 to 2015, the Association of Residents in Radiation Oncology (ARRO) conducted an electronic survey of post-graduate year-5 radiation oncology residents in the United States during the final 3 months of training. Descriptive statistics are reported., Results: Sixty-six chief residents completed the survey in 2013 to 2014 (53% response rate), and 69 completed the survey in 2014 to 2015 (64% response rate). Forty to 85% percent of residents reported inadequate exposure to high-dose rate and low-dose rate brachytherapy. Nearly all residents in both years (>90%) reported adequate clinical experience for the following disease sites: breast, central nervous system, gastrointestinal, genitourinary, head and neck, and lung. However, as few as 56% reported adequate experience in lymphoma or pediatric malignancies. More than 90% of residents had participated in retrospective research projects, with 20% conducting resident-led prospective clinical trials and 50% conducting basic science or translational projects. Most chief residents reported working 60 or fewer hours per week in the clinical/hospital setting and performing fewer than 15 hours per week tasks that were considered to have little or no educational value. There was more than 80% compliance with Accreditation Council for Graduate Medical Education (ACGME) work hour limits. Fifty-five percent of graduating residents intended to join an established private practice group, compared to 25% who headed for academia. Residents perceive the job market to be more competitive than previous years., Conclusions: This first update of the ARRO chief resident survey since the 2007 to 2008 academic year documents US radiation oncology residents' experiences and conditions over a 2-year period. This analysis may serve as a valuable tool for those seeking to improve training of the next generation of oncology leaders., (Copyright © 2016 Elsevier Inc. All rights reserved.)