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Original citation: J Clin Invest. 2023;133(23):e168277. https://doi.org/10.n72/JCI168277. During the preparation of this manuscript, the dose for PMX205 used for in vitro experiments was stated incorrectly in the legend for Figure [...]

The "FLASH effect" is an increased therapeutic index, that is, reduced normal tissue toxicity for a given degree of anti-cancer efficacy, produced by ultra-rapid irradiation delivered on time scales orders of magnitude shorter than currently conventional in the clinic for the same doses. This phenomenon has been observed in numerous preclinical in vivo tumor and normal tissue models. While the underlying biological mechanism(s) remain to be elucidated, a path to clinical implementation of FLASH can be paved by addressing several critical translational questions. Technological questions pertinent to each beam type (eg , electron, proton, photon) also dictate the logical progression of experimentation required to move forward in safe and decisive clinical trials. Here we review the available preclinical data pertaining to these questions and how they may inform strategies for FLASH cancer therapy clinical trials. [ABSTRACT FROM AUTHOR]

Introduction: With locally advanced pancreatic cancer (LAPC), uncontrolled local tumor growth frequently leads to mortality. Advancements in radiotherapy (RT) techniques have enabled conformal delivery of escalated‐dose RT (EDR), which may have potential local control and overall survival (OS) benefits based on retrospective and early prospective studies. With evidence for EDR emerging, we characterized the adoption of EDR across the United States and its associated outcomes. Methods: We searched the National Cancer Database for nonsurgically managed LAPC patients diagnosed between 2004 and 2019. Pancreas‐directed RT with biologically effective doses (BED10) ≥39 and ≤70 Gy was labeled conventional‐dose RT (CDR), and BED10 >70 and ≤132 Gy was labeled EDR. We identified associations of EDR and OS using logistic and Cox regressions, respectively. Results: Among the definitive therapy subset (n = 54,115) of the entire study cohort (n = 91,493), the most common treatments were chemotherapy alone (69%), chemotherapy and radiation (29%), and RT alone (2%). For the radiation therapy subset (n = 16,978), use of pancreas‐directed RT remained between 13% and 17% over the study period (ptrend > 0.999). Using multivariable logistic regression, treatment at an academic/research facility (adjusted odds ratio [aOR] 1.46, p < 0.001) and treatment between 2016 and 2019 (aOR 2.54, p < 0.001) were associated with greater receipt of EDR, whereas use of chemotherapy (aOR 0.60, p < 0.001) was associated with less receipt. Median OS estimates for EDR and CDR were 14.5 months and 13.0 months (p < 0.0001), respectively. For radiation therapy subset patients with available survival data (n = 13,579), multivariable Cox regression correlated EDR (adjusted hazard ratio 0.85, 95% confidence interval 0.80–0.91; p < 0.001) with longer OS versus CDR. Discussion and Conclusions: Utilization of EDR has increased since 2016, but overall utilization of RT for LAPC has remained at less than one in five patients for almost two decades. These real‐world results additionally provide an estimate of effect size of EDR for future prospective trials. [ABSTRACT FROM AUTHOR]

Background Traditional constraints specify that 700 cc of liver should be spared a hepatotoxic dose when delivering liver-directed radiotherapy to reduce the risk of inducing liver failure. We investigated the role of single-photon emission computed tomography (SPECT) to identify and preferentially avoid functional liver during liver-directed radiation treatment planning in patients with preserved liver function but limited functional liver volume after receiving prior hepatotoxic chemotherapy or surgical resection. Methods This phase I trial with a 3 + 3 design evaluated the safety of liver-directed radiotherapy using escalating functional liver radiation dose constraints in patients with liver metastases. Dose-limiting toxicities were assessed 6-8 weeks and 6 months after completing radiotherapy. Results All 12 patients had colorectal liver metastases and received prior hepatotoxic chemotherapy; 8 patients underwent prior liver resection. Median computed tomography anatomical nontumor liver volume was 1584 cc (range = 764-2699 cc). Median SPECT functional liver volume was 1117 cc (range = 570-1928 cc). Median nontarget computed tomography and SPECT liver volumes below the volumetric dose constraint were 997 cc (range = 544-1576 cc) and 684 cc (range = 429-1244 cc), respectively. The prescription dose was 67.5-75 Gy in 15 fractions or 75-100 Gy in 25 fractions. No dose-limiting toxicities were observed during follow-up. One-year in-field control was 57%. One-year overall survival was 73%. Conclusion Liver-directed radiotherapy can be safely delivered to high doses when incorporating functional SPECT into the radiation treatment planning process, which may enable sparing of lower volumes of liver than traditionally accepted in patients with preserved liver function. Trial registration NCT02626312. [ABSTRACT FROM AUTHOR]

PURPOSE Clinical efficiency is a key component of value-based health care. Our objective here was to identify workflow inefficiencies by using time-driven activitybased costing (TDABC) and evaluate the implementation of a new clinical workflow in high-volume outpatient radiation oncology clinics. METHODS Our quality improvement study was conducted with the Departments of GI, Genitourinary (GU), and Thoracic Radiation Oncology at a large academic cancer center and four community network sites. TDABC was used to create process maps and optimize workflow for outpatient consults. Patient encounter metrics were captured with a real-time status function in the electronic medical record. Time metrics were compared using Mann-Whitney U tests. RESULTS Individual patient encounter data for 1,328 consults before the intervention and 1,234 afterward across all sections were included. The median overall cycle time was reduced by 21% in GI (19 minutes), 18% in GU (16 minutes), and 12% at the community sites (9 minutes). The median financial savings per consult were $52 in US dollars (USD) for the GI, $33 USD for GU, $30 USD for thoracic, and $42 USD for the community sites. Patient satisfaction surveys (from 127 of 228 patients) showed that 99% of patients reported that their providers spent adequate time with them and 91% reported being seen by a care provider in a timely manner. CONCLUSION TDABC can effectively identify opportunities to improve clinical efficiency. Implementing workflow changes on the basis of our findings led to substantial reductions in overall encounter cycle times across several departments, as well as high patient satisfaction and significant financial savings. [ABSTRACT FROM AUTHOR]

Simple Summary: This survey study investigates long-term patient-reported quality of life for individuals with low-lying rectal cancers, particularly focusing on the potential impact that ostomies may have on overall, sexual, and urinary quality of life. The findings suggest that patients with ostomies may experience a worse quality of life, affecting various aspects of daily life and relationships. These insights may help to inform patient counseling and shared decision making in the context of evolving rectal cancer treatment paradigms where patients have increasing multidisciplinary options. Background: Despite the increasing utilization of sphincter and/or organ-preservation treatment strategies, many patients with low-lying rectal cancers require abdominoperineal resection (APR), leading to permanent ostomy. Here, we aimed to characterize overall, sexual-, and bladder-related patient-reported quality of life (QOL) for individuals with low rectal cancers. We additionally aimed to explore potential differences in patient-reported outcomes between patients with and without a permanent ostomy. Methods: We distributed a comprehensive survey consisting of various patient-reported outcome measures, including the FACT-G7 survey, ICIQ MLUTS/FLUTS, IIEF-5/FSFI, and a specific questionnaire for ostomy patients. Descriptive statistics and univariate comparisons were used to compared demographics, treatments, and QOL scores between patients with and without a permanent ostomy. Results: Of the 204 patients contacted, 124 (60.8%) returned completed surveys; 22 (18%) of these had a permanent ostomy at the time of survey completion. There were 25 patients with low rectal tumors (≤5 cm from the anal verge) who did not have an ostomy at the time of survey completion, of whom 13 (52%) were managed with a non-operative approach. FACTG7 scores were numerically lower (median 20.5 vs. 22, p = 0.12) for individuals with an ostomy. Sexual function measures IIEF and FSFI were also lower (worse) for individuals with ostomies, but the results were not significantly different. MLUTS and FLUTS scores were both higher in individuals with ostomies (median 11 vs. 5, p = 0.06 and median 17 vs. 5.5, p = 0.01, respectively), suggesting worse urinary function. Patient-reported ostomy-specific challenges included gastrointestinal concerns (e.g., gas, odor, diarrhea) that may affect social activities and personal relationships. Conclusions: Despite a limited sample size, this study provides patient-centered, patient-derived data regarding long-term QOL in validated measures following treatment of low rectal cancers. Ostomies may have multidimensional negative impacts on QOL, and these findings warrant continued investigation in a prospective setting. These results may be used to inform shared decision making for individuals with low rectal cancers in both the settings of organ preservation and permanent ostomy. [ABSTRACT FROM AUTHOR]

Background and Purpose: FLASH or ultra-high dose rate (UHDR) radiation therapy (RT) has gained attention in recent years for its ability to spare normal tissues relative to conventional dose rate (CDR) RT in various preclinical trials. However, clinical implementation of this promising treatment option has been limited because of the lack of availability of accelerators capable of delivering UHDR RT. Commercial options are finally reaching the market that produce electron beams with average dose rates of up to 1000 Gy/s. We established a framework for the acceptance, commissioning, and periodic quality assurance (QA) of electron FLASH units and present an example of commissioning., Methods: A protocol for acceptance, commissioning, and QA of UHDR linear accelerators was established by combining and adapting standards and professional recommendations for standard linear accelerators based on the experience with UHDR at four clinical centers that use different UHDR devices. Non-standard dosimetric beam parameters considered included pulse width, pulse repetition frequency, dose per pulse, and instantaneous dose rate, together with recommendations on how to acquire these measurements., Results: The 6- and 9-MeV beams of an UHDR electron device were commissioned by using this developed protocol. Measurements were acquired with a combination of ion chambers, beam current transformers (BCTs), and dose-rate-independent passive dosimeters. The unit was calibrated according to the concept of redundant dosimetry using a reference setup., Conclusion: This study provides detailed recommendations for the acceptance testing, commissioning, and routine QA of low-energy electron UHDR linear accelerators. The proposed framework is not limited to any specific unit, making it applicable to all existing eFLASH units in the market. Through practical insights and theoretical discourse, this document establishes a benchmark for the commissioning of UHDR devices for clinical use., (© 2024 The Author(s). Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.)

Chemotherapy is often combined with immune checkpoint inhibitor (ICIs) to enhance immunotherapy responses. Despite the approval of chemo-immunotherapy in multiple human cancers, many immunologically cold tumors remain unresponsive. The mechanisms determining the immunogenicity of chemotherapy are elusive. Here, we identify the ER stress sensor IRE1α as a critical checkpoint that restricts the immunostimulatory effects of taxane chemotherapy and prevents the innate immune recognition of immunologically cold triple-negative breast cancer (TNBC). IRE1α RNase silences taxane-induced double-stranded RNA (dsRNA) through regulated IRE1-dependent decay (RIDD) to prevent NLRP3 inflammasome-dependent pyroptosis. Inhibition of IRE1α in Trp53 -/- TNBC allows taxane to induce extensive dsRNAs that are sensed by ZBP1, which in turn activates NLRP3-GSDMD-mediated pyroptosis. Consequently, IRE1α RNase inhibitor plus taxane converts PD-L1-negative, ICI-unresponsive TNBC tumors into PD-L1 high immunogenic tumors that are hyper-sensitive to ICI. We reveal IRE1α as a cancer cell defense mechanism that prevents taxane-induced danger signal accumulation and pyroptotic cell death., Competing Interests: Declaration of interests M.F.R. receives research funding from Pfizer and Genentech and consulting fees from Novartis, Seagen, Macrogenics, and AstraZeneca. M.F.R. is the PI of clinical trial NCT03950570. X.C. reports previous research funding from Fosun Pharma. M.J.E. holds patents and receives income from Veracyte on the PAM50-based products, Prosigna., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: There currently are no established formal mentorship and training programs for radiation oncology (RO) trainees to learn trial design, creation, writing, or implementation. There only exists informal training on analyzing clinical trials in RO residency programs. The integration of a longitudinal formal training and mentorship program for clinical trialists-consisting of clinical trial education, design, mentorship, and implementation during the RO residency education-will give residents not only formal teaching in the subject but also strong tools and requisite mentorship in hopes to help them succeed as future academic physicians and leaders in the field of RO., Methods and Materials: We developed a clinical trial training pathway in 2018 at MD Anderson Cancer Center, proposing it as a pilot program. The "Fletcher-Cox Pathway" was accepted with a highly positive response by trainees and is now offered as a standard option to RO trainees at our institution., Results: With the guidance of their principal investigator, residents participating in this pathway design and submit a clinical trial for institutional review board review. In 2019, after implementation of the pilot program, 4 of the incoming 7 residents joined the pathway. The program continues, and the current cohort of trainees have received training in clinical trial design and worked with dedicated mentor(s) regarding clinical trial ideas; their studies are currently accruing patients., Conclusions: This pilot program has been viewed by trainees and mentors as successful; it highlights how a structured approach meets a clear need within RO training. We envision the creation of a national platform to increase access, whereby programs adopt this clinical trialist educational pathway, which ultimately leads to the development of a robust clinical trial community with communal resources. We hope that this not only improves and provides educational initiatives to all trainees but also initiates further collaboration., Competing Interests: None., (© 2024 The Authors.)

Previously, a synchrotron-based horizontal proton beamline (87.2 MeV) was successfully commissioned to deliver radiation doses in FLASH and conventional dose rate modes to small fields and volumes. In this study, we developed a strategy to increase the effective radiation field size using a custom robotic motion platform to automatically shift the positions of biological samples. The beam was first broadened with a thin tungsten scatterer and shaped by customized brass collimators for irradiating cell/organoid cultures in 96-well plates (a 7-mm-diameter circle) or for irradiating mice (1-cm 2 square). Motion patterns of the robotic platform were written in G-code, with 9-mm spot spacing used for the 96-well plates and 10.6-mm spacing for the mice. The accuracy of target positioning was verified with a self-leveling laser system. The dose delivered in the experimental conditions was validated with EBT-XD film attached to the 96-well plate or the back of the mouse. Our film-measured dose profiles matched Monte Carlo calculations well (1D gamma pass rate >95%). The FLASH dose rates were 113.7 Gy/s for cell/organoid irradiation and 191.3 Gy/s for mouse irradiation. These promising results indicate that this robotic platform can be used to effectively increase the field size for preclinical experiments with proton FLASH., Competing Interests: Conflict of Interest Kiminori Iga is currently employed by Hitachi Ltd. Other authors declare no conflicts of interest.

Background: Although escalated doses of radiation therapy (RT) for intrahepatic cholangiocarcinoma (iCCA) are associated with durable local control (LC) and prolonged survival, uncertainties persist regarding personalized RT based on biological factors. Compounding this knowledge gap, the assessment of RT response using traditional size-based criteria via computed tomography (CT) imaging correlates poorly with outcomes. We hypothesized that quantitative measures of enhancement would more accurately predict clinical outcomes than size-based assessment alone and developed a model to optimize RT., Methods: Pre-RT and post-RT CT scans of 154 patients with iCCA were analyzed retrospectively for measurements of tumor dimensions (for RECIST) and viable tumor volume using quantitative European Association for Study of Liver (qEASL) measurements. Binary classification and survival analyses were performed to evaluate the ability of qEASL to predict treatment outcomes, and mathematical modeling was performed to identify the mechanistic determinants of treatment outcomes and to predict optimal RT protocols., Results: Multivariable analysis accounting for traditional prognostic covariates revealed that percentage change in viable volume following RT was significantly associated with OS, outperforming stratification by RECIST. Binary classification identified ≥33% decrease in viable volume to optimally correspond to response to RT. The model-derived, patient-specific tumor enhancement growth rate emerged as the dominant mechanistic determinant of treatment outcome and yielded high accuracy of patient stratification (80.5%), strongly correlating with the qEASL-based classifier., Conclusion: Following RT for iCCA, changes in viable volume outperformed radiographic size-based assessment using RECIST for OS prediction. CT-derived tumor-specific mathematical parameters may help optimize RT for resistant tumors., Competing Interests: Conflicts of interest: BD reports honoraria from Sermo, Inc and funding from the Radiological Society of North America. EBH reports grants from Merck Serono. CMT reports a consulting/advisory role with Accuray. ACK reports ownership of shares in Aravive, Inc. PD reports honoraria from ASTRO, ASCO, Imedex, and Bayer. EJK reports grants from National Institutes of Health, Stand Up 2 Cancer, MD Anderson Cancer Center, Philips Healthcare, Elekta, and GE Healthcare; personal fees from RenovoRx and Taylor and Francis; and a consulting/advisory role with Augmenix. All reported conflicts are outside the current work.

Purpose: Proton FLASH has been investigated using cyclotron and synchrocyclotron beamlines but not synchrotron beamlines. We evaluated the impact of dose rate (ultra-high [UHDR] vs. conventional [CONV]) and beam configuration (shoot-through [ST] vs. spread-out-Bragg-peak [SOBP]) on acute radiation-induced gastrointestinal toxicity (RIGIT) in mice. We also compared RIGIT between synchrotron-based protons and linac-based electrons with matched mean dose rates., Methods and Materials: We administered abdominal irradiation (12-14 Gy single fraction) to female C57BL/6J mice with an 87 MeV synchrotron-based proton beamline (2 cm diameter field size as a lateral beam). Dose rates were 0.2 Gy/s (S-T pCONV), 0.3 Gy/s (SOBP pCONV), 150 Gy/s (S-T pFLASH), and 230 Gy/s (SOBP pFLASH). RIGIT was assessed by the jejunal regenerating crypt assay and survival. We also compared responses to proton [pFLASH and pCONV] with responses to electron CONV (eCONV, 0.4 Gy/s) and electron FLASH (eFLASH, 188-205 Gy/s)., Results: The number of regenerating jejunal crypts at each matched dose was lowest for pFLASH (similar between S-T and SOBP), greater and similar between pCONV (S-T and SOBP) and eCONV, and greatest for eFLASH. Correspondingly, mice that received pFLASH SOBP had the lowest survival rates (50% at 50 days), followed by pFLASH S-T (80%), and pCONV SOBP (90%), but 100% of mice receiving pCONV S-T survived (log-rank P = 0.047 for the four groups)., Conclusions: Our findings are consistent with an increase in RIGIT after synchrotron-based pFLASH versus pCONV. This negative proton-specific FLASH effect versus linac-based electron irradiation underscores the importance of understanding the physical and biological factors that will allow safe and effective clinical translation.

We hypothesized that pre-consult patient education videos can improve patient understanding about their diagnosis, lead to high satisfaction and low distress. In this pilot study, we developed a patient education video curriculum for patients with newly-diagnosed anal cancer. Comprehension of key content was evaluated by comparing pre- and post-test scores. Patient satisfaction scores were collected. Patient distress scores (0-10) were collected at the beginning of their consult visit prior to seeing the physician. We found that patient education videos prior to consult improved patient understanding, resulted in high patient satisfaction, and low patient distress at the time of consult., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)