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Purpose: To test the hypothesis that increased acute toxicity, measured using subdomains reflective of epithelial cell damage, will be associated with reduced late biochemical failure, as a surrogate for tumor radiosensitivity.Methods and Materials: The study design was retrospective, with discovery and validation cohorts involving routinely collected data. Eligible patients had prostate cancer, underwent radiation therapy with curative intent, and had acute toxicity assessed prospectively. The discovery cohort was from a single institution. Genitourinary and gastrointestinal acute toxicity related to epithelial cell damage (hematuria, dysuria, proctitis, or mucus) were related to freedom from late biochemical failure (FFBF; nadir + 2). The validation cohort was from two separate institutions.Results: In all, 503 patients were included in the discovery cohort and 658 patients in the validation cohort. In the validation cohort, patients with acute radiation toxicity reflecting epithelial damage had a longer FFBF on both univariate (hazard ratio [HR] 0.37; P = .004) and multivariate (HR 0.45; P = .035) analysis. The impact of acute toxicity on late FFBF seemed to be greater in patients treated with androgen deprivation (HR 0.19) than in those without (HR 0.48).Conclusion: Patients reporting acute radiation toxicity reflective of epithelial cell damage during definitive radiation therapy for prostate cancer have significantly longer FFBF, consistent with an underlying genetic link between normal tissue and tumor radiosensitivity. [ABSTRACT FROM AUTHOR]

Purpose: To conduct a retrospective analysis within a large university teaching hospital, comparing outcomes between patients receiving either radical surgery or radiotherapy as curative treatment for bladder cancer. Patients and Methods: Between March 1996 and December 2000, 169 patients were treated radically for muscle-invasive bladder cancer. Data were collected from patient notes. Statistical analyses were performed using Kaplan-Meier methods and Cox proportional hazards regression analysis to compare radiotherapy and surgical outcome data. Results: There was no difference in overall, cause-specific, and distant recurrence-free survival at 5 years between the two groups, despite the radiotherapy group being older (median age, 75.3 years vs. 68.2 years). There were 31 local bladder recurrences in the radiotherapy group (24 solitary), but there was no significant difference in distant recurrence-free survival. In a more recent (2002–2006) cohort, the median age of radiotherapy patients but not the cystectomy patients was higher than in the 1996–2000 cohort (78.4 years vs. 75.3 years for radiotherapy and 67.9 years vs. 68.2 years for surgery). Conclusions: Although the patients undergoing radical cystectomy were significantly younger than the radiotherapy patients, treatment modality did not influence survival. Bladder cancer patients are an increasingly elderly group. Radical radiotherapy is a viable treatment option for these patients, with the advantage of organ preservation. [Copyright &y& Elsevier]

The use of magnetic resonance imaging (MRI) in radiotherapy planning is becoming more widespread, particularly with the emergence of MRI-guided radiotherapy systems. Existing guidelines for defining the prostate bed clinical target volume (CTV) show considerable heterogeneity. This study aimed to establish baseline interobserver variability (IOV) for prostate bed CTV contouring on MRI, develop international consensus guidelines, and evaluate its effect on IOV. Participants delineated the CTV on 3 MRI scans, obtained from the Elekta Unity MR-Linac, as per their normal practice. Radiation oncologist contours were visually examined for discrepancies, and interobserver comparisons were evaluated against simultaneous truth and performance level estimation (STAPLE) contours using overlap metrics (Dice similarity coefficient and Cohen's kappa), distance metrics (mean distance to agreement and Hausdorff distance), and volume measurements. A literature review of postradical prostatectomy local recurrence patterns was performed and presented alongside IOV results to the participants. Consensus guidelines were collectively constructed, and IOV assessment was repeated using these guidelines. Sixteen radiation oncologists' contours were included in the final analysis. Visual evaluation demonstrated significant differences in the superior, inferior, and anterior borders. Baseline IOV assessment indicated moderate agreement for the overlap metrics while volume and distance metrics demonstrated greater variability. Consensus for optimal prostate bed CTV boundaries was established during a virtual meeting. After guideline development, a decrease in IOV was observed. The maximum volume ratio decreased from 4.7 to 3.1 and volume coefficient of variation reduced from 40% to 34%. The mean Dice similarity coefficient rose from 0.72 to 0.75 and the mean distance to agreement decreased from 3.63 to 2.95 mm. Interobserver variability in prostate bed contouring exists among international genitourinary experts, although this is lower than previously reported. Consensus guidelines for MRI-based prostate bed contouring have been developed, and this has resulted in an improvement in contouring concordance. However, IOV persists and strategies such as an education program, development of a contouring atlas, and further refinement of the guidelines may lead to additional improvements. [ABSTRACT FROM AUTHOR]

Purpose: Small cell carcinoma of the bladder (SCCB) is rare, accounting for less than 1% of all bladder carcinomas. It is aggressive, and outcomes are poor as a result of its early metastatic spread. Owing to its rarity, there are limitations on data to propose standardized management pathways.Methods and Materials: We conducted a retrospective analysis of patients presenting with pure or predominant-histology SCCB to 26 institutions in the United Kingdom between 2006 and 2016. The data cutoff date was February 1, 2018. We report patient characteristics, treatment received, and subsequent clinical outcomes.Results: A total of 409 eligible patients were included. Among these, 306 (74.8%) were male, the median age was 71 years (range, 35-96 years), and 189 patients (46.2%) had pure-histology SCCB. At data cutoff, 301 patients (73.6%) had died. The median overall survival (OS) was 15.9 months (95% CI, 13.2-18.7 months). Two hundred patients (48.9%) were confirmed to have bladder-confined disease (N0, M0), with a median OS of 28.3 months (95% CI, 20.9-35.8 months), versus a median OS of 12.7 months (95% CI, 10.9-14.6 months) for the 172 patients (42.1%) with confirmed N1-3 and/or M1 disease (hazard ratio [HR], 2.03; 95% CI, 1.58-2.60; P < .001). A total of 247 patients (61.5%) received primary chemotherapy, with a median OS of 21.6 months (95% CI, 15.5-27.6 months), versus a median OS of 9.1 months (95% CI, 5.4-12.8 months) in patients who did not receive primary chemotherapy (HR, 0.46; 95% CI, 0.37-0.59; P < .001). Choice of chemotherapy agent did not alter outcomes. For those with bladder-confined disease, 61 (30.5%) underwent cystectomy, and 104 (52.0%) received radiation therapy. Survival outcomes were similar for both cystectomy and radiation therapy. Only 6 patients (1.5%) were identified as having brain metastases at any time point.Conclusions: To our knowledge, this is the largest retrospective study of all-stage SCCB to date. Patients have a poor prognosis overall, but survival is improved in those able to receive chemotherapy and with organ-confined disease. Brain metastases are rare. [ABSTRACT FROM AUTHOR]

The premise that therapies targeting immune checkpoints can enhance radiation therapy (RT)-induced antitumor immunity is being explored rigorously in the preclinical setting, and early clinical trials testing this hypothesis are beginning to report. Although such approaches might prove efficacious in certain settings, it is likely that many tumor types, particularly those that have a deeply immune-suppressed microenvironment with little or no T cell infiltration, will require alternative approaches. Thus, there is now considerable drive to develop novel immune modulatory therapies that target other areas of the cancer immunity cycle. Toll-like receptors (TLRs) are expressed on sentinel immune cells and play a key role in the host defense against invading pathogens. Innate sensing via TLR-mediated detection of pathogen-derived molecular patterns can lead to maturation of antigen-presenting cells and downstream activation of adaptive immunity. After demonstrating promising efficacy in preclinical studies, drugs that stimulate TLR have been approved for use clinically, albeit to a limited extent. There is a growing body of preclinical evidence that novel agonists targeting TLR3, TLR7/8, or TLR9 in combination with RT might lead to enhanced antitumor immunity. Mechanistic studies have revealed that TLR agonists enhance dendritic cell-mediated T cell priming after RT, in some cases leading to the generation of systemic antitumor immunity and immune memory. In this report, we describe results from preclinical studies that advocate the strategy of combining RT with TLR agonists, discuss reported mechanisms of action, and explore the exciting opportunities of how this approach may be successfully translated into clinical practice. [ABSTRACT FROM AUTHOR]

Purpose: Whole pelvis radiation therapy (WPRT) may improve clinical outcomes over prostate-only radiation therapy (PORT) in high-risk prostate cancer patients by sterilization of micrometastatic nodal disease, provided there is optimal control of the primary site.Methods and Materials: A prospective multicenter cohort study of eligible patients (stage ≥T2c, Gleason score ≥7 or presenting prostate-specific antigen ≥10) treated between 2009 and 2013 were enrolled in a United Kingdom national protocol delivering combined external beam radiation therapy and high-dose-rate brachytherapy. Centers elected to deliver WPRT, 46 Gy in 23 fractions or PORT 37.5 Gy in 15 fractions with 15 Gy single dose high-dose-rate brachytherapy. The primary endpoint was biochemical progression-free survival (bPFS). Secondary endpoints were overall survival, genitourinary, and gastrointestinal toxicity. This was not a randomized comparison and was subject to bias; the findings are therefore hypothesis generating, but not conclusive.Results: Eight hundred and twelve patients were entered; 401 received WPRT and 411 received PORT. With a median follow-up of 4.7 years, 5-year bPFS rates for WPRT versus PORT arms were 89% versus 81% (P = .007) for all patients and 84% versus 77% (P = .001) for high-risk patients. Differences in bPFS remained significant after accounting for Gleason score, presenting prostate-specific antigen, T stage, and androgen deprivation therapy duration as covariates. There was no difference in overall survival. The overall post treatment toxicities across both cohorts were low with no greater than 1.5% of ≥grade 3 toxicities at any follow-up time point. WPRT increased both prevalence and cumulative incidence of acute genitourinary toxicity (P = .004) and acute gastrointestinal toxicity (P = .003). No difference in late radiation toxicity was observed.Conclusions: A significant improvement in 5-year bPFS was seen in intermediate and high-risk prostate cancer treated with WPRT compared with PORT in a combined external beam radiation therapy and brachytherapy schedule with no increase in late radiation toxicity. [ABSTRACT FROM AUTHOR]

Purpose: CHHiP is a randomized trial evaluating moderately hypofractionated radiation therapy for treatment of localized prostate cancer. Of all participants, 97% of them had concurrent short-course hormone therapy (HT), either luteinizing hormone-releasing hormone analog (LHRHa) or 150 mg of bicalutamide daily. This exploratory analysis compares efficacy and side effects in a nonrandomized comparison.Methods and Materials: In our study, 2700 patients received LHRHa and 403 received bicalutamide. The primary endpoint was biochemical/clinical failure. Groups were compared with Cox regression adjusted for various prognostic factors and stratified by radiation therapy dose. A key secondary endpoint was erectile dysfunction (ED) assessed by clinicians (using scores from Late Effects on Normal Tissues: Subjective/Objective/Management [LENT-SOM] subjective erectile function for vaginal penetration) and patients (single items within the University of California-Los Angeles Prostate Cancer Index [UCLA PCI] and Expanded Prostate Cancer Index Composite [EPIC]-50 questionnaires) at 2 years and compared between HT regimens by χ2 trend test.Results: Bicalutamide patients were significantly younger (median 67 vs 69 years LHRHa). Median follow-up was 9.3 years. There was no difference in biochemical or clinical failure with an adjusted hazard ratio or 0.97 (95% confidence interval, 0.77-1.23; P = .8). At 2 years, grade ≥2 LENT-SOM ED was reported in significantly more LHRHa patients (313 out of 590; 53%) versus bicalutamide (17 out of 68; 25%) (P < .0001). There were no differences in ED seen with UCLA-PCI and EPIC-50 questionnaires.Conclusions: In this nonrandomized comparison, there was no evidence of a difference in efficacy according to type of HT received. Bicalutamide preserved clinician assessed (LENT-SOM) erectile function at 2 years but patient-reported outcomes were similar between groups. [ABSTRACT FROM AUTHOR]

Purpose: High-field magnetic resonance-linear accelerators (MR-Linacs), linear accelerators combined with a diagnostic magnetic resonance imaging (MRI) scanner and online adaptive workflow, potentially give rise to novel online anatomic and response adaptive radiation therapy paradigms. The first high-field (1.5T) MR-Linac received regulatory approval in late 2018, and little is known about clinical use, patient tolerability of daily high-field MRI, and toxicity of treatments. Herein we report the initial experience within the MOMENTUM Study (NCT04075305), a prospective international registry of the MR-Linac Consortium.Methods and Materials: Patients were included between February 2019 and October 2020 at 7 institutions in 4 countries. We used descriptive statistics to describe the patterns of care, tolerability (the percentage of patients discontinuing their course early), and safety (grade 3-5 Common Terminology Criteria for Adverse Events v.5 acute toxicity within 3 months after the end of treatment).Results: A total 943 patients participated in the MOMENTUM Study, 702 of whom had complete baseline data at the time of this analysis. Patients were primarily male (79%) with a median age of 68 years (range, 22-93) and were treated for 39 different indications. The most frequent indications were prostate (40%), oligometastatic lymph node (17%), brain (12%), and rectal (10%) cancers. The median number of fractions was 5 (range, 1-35). Six patients discontinued MR-Linac treatments, but none due to an inability to tolerate repeated high-field MRI. Of the 415 patients with complete data on acute toxicity at 3-month follow-up, 18 (4%) patients experienced grade 3 acute toxicity related to radiation. No grade 4 or 5 acute toxicity related to radiation was observed.Conclusions: In the first 21 months of our study, patterns of care were diverse with respect to clinical utilization, body sites, and radiation prescriptions. No patient discontinued treatment due to inability to tolerate daily high-field MRI scans, and the acute radiation toxicity experience was encouraging. [ABSTRACT FROM AUTHOR]

Purpose: Many muscle-invasive bladder cancers are hypoxic, which limits the efficacy of radiation therapy. Hypoxia modification using carbogen and nicotinamide has been tested in a phase 3 trial, Bladder Carbogen Nicotinamide. We present mature follow-up data with biomarker predictions of outcomes.Methods and Materials: Bladder Carbogen Nicotinamide is a prospective, phase 3, multicenter, randomized, 2-arm, nonblinded clinical trial. Participants were randomized to receive radical radiation therapy (RT; control arm) alone or with the addition of carbogen (98% O2; 2% CO2) and nicotinamide (CON). Patients with muscle-invasive or high-grade non-muscle invasive bladder cancer were included. Tumor tissue was collected at entry and was analyzed for tumor necrosis, hypoxia (24-gene signature), and basal and luminal tumor molecular subtypes. Overall survival (OS) and disease-free survival and relationships with biomarker status outcomes are analyzed using multivariable Cox regression and log-rank analysis.Results: We analyzed 333 patients with a median follow-up of 10.3 years. The 10-year OS rates were 30% (95% confidence interval [CI], 0.23-0.39) in RT + CON patients and 24% (95% CI, 0.18-0.33) in the RT-alone patients (hazard ratio [HR], 0.80; 95% CI, 0.61-1.04; P = .08). The greatest benefit from CON was seen in patients with tumor necrosis (n = 79; 5-year OS, 53% vs. 33% in patients without tumor necrosis; HR, 0.59; 95% CI, 0.36-0.99; P = .04). Cases with a high hypoxia gene score (n = 75) had a 5-year OS rate of 51%, compared to 34% for a low score (HR, 0.64; 95% CI, 0.38-1.08; P = .09); those with the basal molecular subtype (n = 70) had a 5-year OS rate of 58%, compared to 38% for those with the luminal subtype (HR, 0.58; 95% CI, 0.32-1.06; P = .08).Conclusions: Although the improvement in long-term OS in the whole population is not statistically significant, patients selected by necrosis and high hypoxia gene score benefitted from hypoxia modification. [ABSTRACT FROM AUTHOR]

Purpose: Numerous publications during the COVID-19 pandemic recommended the use of hypofractionated radiation therapy. This project assessed aggregate changes in the quality of the evidence supporting these schedules to establish a comprehensive evidence base for future reference and highlight aspects for future study.Methods and Materials: Based on a systematic review of published recommendations related to dose fractionation during the COVID-19 pandemic, 20 expert panelists assigned to 14 disease groups named and graded the highest quality of evidence schedule(s) used routinely for each condition and also graded all COVID-era recommended schedules. The American Society for Radiation Oncology quality of evidence criteria were used to rank the schedules. Process-related statistics and changes in distributions of quality ratings of the highest-rated versus recommended COVID-19 era schedules were described by disease groups and for specific clinical scenarios.Results: From January to May 2020 there were 54 relevant publications, including 233 recommended COVID-19-adapted dose fractionations. For site-specific curative and site-specific palliative schedules, there was a significant shift from established higher-quality evidence to lower-quality evidence and expert opinions for the recommended schedules (P = .022 and P < .001, respectively). For curative-intent schedules, the distribution of quality scores was essentially reversed (highest levels of evidence "pre-COVID" vs "in-COVID": high quality, 51.4% vs 4.8%; expert opinion, 5.6% vs 49.3%), although there was variation in the magnitude of shifts between disease sites and among specific indications.Conclusions: A large number of publications recommended hypofractionated radiation therapy schedules across numerous major disease sites during the COVID-19 pandemic, which were supported by a lower quality of evidence than the highest-quality routinely used dose fractionation schedules. This work provides an evidence-based assessment of these potentially practice-changing recommendations and informs individualized decision-making and counseling of patients. These data could also be used to support radiation therapy practices in the event of second waves or surges of the pandemic in new regions of the world. [ABSTRACT FROM AUTHOR]

Purpose: Although high-level evidence supports moderately hypofractionated radiation therapy for definitive prostate treatment, there is less evidence for its use in the postprostatectomy setting. We externally validated a contemporary nomogram predicting biochemical failure (BF) after salvage radiation therapy (SRT) and report long-term disease control outcomes for hypofractionated SRT to the prostate bed.Methods and Materials: A retrospective review was performed for 112 patients treated with hypofractionated SRT (52.5 Gy in 20 fractions using 3-dimensional conformal radiation therapy) for pT2-4R0-1N0/XM0 prostate adenocarcinoma, with postoperative prostate-specific antigen (PSA) greater than 0.1 ng/mL or rising. Freedom from BF (FFBF), distant metastasis, cancer-specific mortality, and overall survival were analyzed from commencement of radiation therapy. Cox regression was performed on FFBF to account for covariates. BF was defined as a PSA ≥0.4 ng/mL and rising after SRT. Early SRT was defined as SRT commencing at a pre-SRT PSA of ≤0.2 ng/mL.Results: Median follow-up was 10.0 years (interquartile range, 9.3-10.7 years), median pre-SRT PSA was 0.4 ng/mL, and androgen deprivation therapy was used in 14% of patients. The 5/10-year FFBF, distant metastasis, cancer-specific mortality, and overall survival were 68%/51%, 7%/16%, 5%/11%, and 90%/75%, respectively. FFBF for early SRT compared with late SRT was 81% versus 66% at 5 years and 68% versus 49% at 10 years. On multivariable analysis, pre-SRT PSA, International Society of Urologic Pathology grade group, seminal vesicle invasion, and androgen deprivation therapy use were associated with FFBF. The nomogram c-index was 0.67, and it overestimated FFBF by 10% and 15% at 5 and 10 years, respectively, with confidence intervals overlapping the line of unity.Conclusions: Hypofractionated SRT provides long-term disease control outcomes comparable to conventionally fractionated radiation therapy. Early SRT provides improved disease control, with two-thirds of patients with pre-SRT PSA of ≤0.2 ng/mL free of BF at 10 years. We performed the first external validation of the Tendulkar salvage nomogram, which showed a robust model performance. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effectiveness of palliative pelvic radiation therapy (PRT) in patients with bladder cancer and identify factors associated with treatment outcome.Methods and Materials: Patients with bladder cancer receiving PRT were identified retrospectively from 2 cancer centers between 2014 and 2017. Patients were stratified by age, stage, performance status, comorbidities, previous chemotherapy, previous radiation therapy, and radiation therapy protocol. Patients were followed up at 6 weeks after radiation therapy (RT). Median overall survival (mOS) from the last fraction of RT was calculated. Death within 30 days of RT or noncompletion of treatment were considered as futile treatment.Results: Two hundred forty-one patients were identified as receiving PRT. A variety of RT protocols were used: 8 Gy in 1 fraction (11%), 21 Gy in 3 fractions (15%), 20 Gy in 5 fractions (18%), 36 Gy in 6 fractions (36%), and 27.5 to 30 Gy in 8 to 10 fractions (18%). Thirty-eight percent of patients were of poor performance status (Eastern Cooperative Oncology Group performance status ≥3), and 46.5% had significant comorbidities (Adult Comorbidity Evaluation-27 ≥2). The mOS from the last fraction of RT was 153 days (0-1289 days). The 30-day mortality after radiation therapy was 18% (n = 44), and the rate of incomplete planned radiation therapy treatment was 14% (n = 33). First follow-up information was available in 62% (n = 150) of patients. Median time to this follow-up was 49 days (14-238 days). At first follow-up at about 6 weeks after the last fraction of radiation therapy, symptoms were reported in 150 of 200 (75%) living patients; 80 of 150 (53%) patients reported improvement in symptoms after treatment. There were significant differences in mOS with stage, performance status, and comorbidities.Conclusions: One in 4 patients either did not complete the planned RT course or died within 30 days of treatment. These patients were unlikely to have received maximal benefit from treatment but may have experienced side effects, making treatment futile. Patients with good performance status and earlier stage disease survived longer. Patient selection and comprehensive assessment are crucial in selecting appropriate patients for treatment. [ABSTRACT FROM AUTHOR]

Organ-confined muscle-invasive bladder cancer is treated with cystectomy or bladder preservation techniques, including radiation therapy. There are currently no biomarkers to inform management decisions and aid patient choice. Previously we showed high levels of MRE11 protein, assessed by immunohistochemistry (IHC), predicted outcome after radiation therapy, but not cystectomy. Therefore, we sought to develop the MRE11 IHC assay for clinical use and define its relationship to clinical outcome in samples from 2 major clinical trials. Samples from the BCON and BC2001 randomized controlled trials and a cystectomy cohort were stained using automated IHC methods and scored for MRE11 in 3 centers in the United Kingdom. Despite step-wise creation of scoring cards and standard operating procedures for staining and interpretation, there was poor intercenter scoring agreement (kappa, 0.32; 95% confidence interval, 0.17-0.47). No significant associations between MRE11 scores and cause-specific survival were identified in BCON (n = 132) and BC2001 (n = 221) samples. Reoptimized staining improved agreement between scores from BCON tissue microarrays (n = 116), but MRE11 expression was not prognostic for cause-specific survival. Manual IHC scoring of MRE11 was not validated as a reproducible biomarker of radiation-based bladder preservation success. There is a need for automated quantitative methods or a reassessment of how DNA-damage response relates to clinical outcomes. [ABSTRACT FROM AUTHOR]

Purpose: Outcome data on radiation therapy for prostate cancer in an elderly population are sparse. The CHHiP (Conventional or Hypofractionated High Dose Intensity Modulated Radiotherapy in Prostate Cancer) trial provides a large, prospectively collected, contemporary dataset in which to explore outcomes by age.Methods and Materials: CHHiP participants received 3 to 6 months of androgen deprivation therapy and were randomly assigned (1:1:1) to receive 74 Gy in 37 fractions (conventional fractionation), 60 Gy in 20 fractions, or 57 Gy in 19 fractions. Toxicity was assessed using clinician-reported outcome (CRO) and patient-reported outcome questionnaires. Participants were categorized as aged < 75 years or ≥ 75 years. Outcomes were compared by age group.Results: Of 3216 patients, 491 (15%) were aged ≥ 75 years. There was no difference in biochemical or clinical failure rates between the groups aged < 75 years and ≥ 75 years for any of the fractionation schedules. In the group aged ≥ 75 years, biochemical or clinical failure-free rates favored hypofractionation, and at 5 years, they were 84.7% for 74 Gy, 91% for 60 Gy, and 87.7% for 57 Gy. The incidence of CRO (grade 3) acute bowel toxicity was 2% in both age groups. The incidence of grade 3 acute bladder toxicity was 8% in patients aged < 75 years and 7% in those aged ≥ 75 years. The 5-year cumulative incidence of CRO grade ≥ 2 late bowel side effects was similar in both age groups. However, in the group aged ≥ 75 years, there was a suggestion of a higher cumulative incidence of bowel bother (small or greater) with 60 Gy compared with 74 Gy and 57 Gy. Patient-reported bladder bother was slightly higher in the group aged ≥ 75 years than the group aged < 75 years, and there was a suggestion of a lower cumulative incidence of bladder bother with 57 Gy compared with 74 Gy and 60 Gy in patients aged ≥ 75 years, which was not evident in those aged < 75 years.Conclusions: Hypofractionated radiation therapy appears to be well tolerated and effective in men aged ≥ 75 years. The 57-Gy schedule has potential advantages in that it may moderate long-term side effects without compromising treatment efficacy in this group. [ABSTRACT FROM AUTHOR]

Radiation therapy to the prostate involves increasingly sophisticated delivery techniques and changing fractionation schedules. With a low estimated α/β ratio, a larger dose per fraction would be beneficial, with moderate fractionation schedules rapidly becoming a standard of care. The integration of a magnetic resonance imaging (MRI) scanner and linear accelerator allows for accurate soft tissue tracking with the capacity to replan for the anatomy of the day. Extreme hypofractionation schedules become a possibility using the potentially automated steps of autosegmentation, MRI-only workflow, and real-time adaptive planning. The present report reviews the steps involved in hypofractionated adaptive MRI-guided prostate radiation therapy and addresses the challenges for implementation. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to assess the tolerability of concurrent chemoradiation therapy with gemcitabine (GemX) in muscle invasive bladder cancer following neoadjuvant chemotherapy (neoGemX) by use of patient- and provider-reported outcomes.Methods and Materials: Seventy-eight patients were treated with GemX. Thirty-eight received prior neoadjuvant chemotherapy (NAC). Patients were prospectively assessed during treatment and at 6 weeks and 12 months after treatment completion. Radiation therapy was given to a total dose of 52.5 Gy in 20 fractions with weekly concurrent gemcitabine chemotherapy, 100 mg/m2. Toxicity was assessed by the care provider and by a patient-reported outcome questionnaire collecting scores on the late effects in normal tissues-subjective, objective, management, and analytic scales and was statistically compared at baseline and 12 months, as well as between the neoGemX and GemX groups.Results: The median duration of follow-up was 15.9 months. The radiation therapy completion rate was 95%, and 96% of patients completed at least 3 cycles of gemcitabine. Bowel toxicity of grade 3 or greater was reported in 7 of 38 patients (18%) in the neoGemX group and 5 of 25 (20%) in the GemX group. Three GemX and two neoGemX patients had grade 3 or greater urinary toxicity. Forty-nine patients completed questionnaires and were included in the analysis. Scores on the late effects in normal tissues-subjective, objective, management, and analytic scales showed an expected peak by week 4 of treatment. There was no statistically significant difference between mean scores at baseline and 12 months after treatment completion or between the neoGemX and GemX groups.Conclusions: This study demonstrates that GemX, alone or following NAC, has manageable toxicity and acceptable treatment completion rates. Allowing for small patient numbers and the nonrandomized nature of this study, these results do not suggest any additional toxicity from the use of NAC prior to GemX. [ABSTRACT FROM AUTHOR]

Purpose: To develop multi-institutional consensus clinical target volumes (CTVs) and organs at risk (OARs) for male and female bladder cancer patients undergoing adjuvant radiation therapy (RT) in clinical trials.Methods and Materials: We convened a multidisciplinary group of bladder cancer specialists from 15 centers and 5 countries. Six radiation oncologists and 7 urologists participated in the development of the initial contours. The group proposed initial language for the CTVs and OARs, and each radiation oncologist contoured them on computed tomography scans of a male and female cystectomy patient with input from ≥1 urologist. On the basis of the initial contouring, the group updated its CTV and OAR descriptions. The cystectomy bed, the area of greatest controversy, was contoured by another 6 radiation oncologists, and the cystectomy bed contouring language was again updated. To determine whether the revised language produced consistent contours, CTVs and OARs were redrawn by 6 additional radiation oncologists. We evaluated their contours for level of agreement using the Landis-Koch interpretation of the κ statistic.Results: The group proposed that patients at elevated risk for local-regional failure with negative margins should be treated to the pelvic nodes alone (internal/external iliac, distal common iliac, obturator, and presacral), whereas patients with positive margins should be treated to the pelvic nodes and cystectomy bed. Proposed OARs included the rectum, bowel space, bone marrow, and urinary diversion. Consensus language describing the CTVs and OARs was developed and externally validated. The revised instructions were found to produce consistent contours.Conclusions: Consensus descriptions of CTVs and OARs were successfully developed and can be used in clinical trials of adjuvant radiation therapy for bladder cancer. [ABSTRACT FROM AUTHOR]

Broadly, medical education e-learning is equivalent to in-person in student satisfaction, knowledge, skills, and outcomes. However, when e-learning is best used, and in what form is still being determined. For instance, e-learning with greater interactivity, practice, and feedback is associated with improved learner satisfaction and outcomes. Considering the computer-basis of radiation treatment planning, radiation oncology residents plausibly may prefer virtual treatment planning and review formats. We aimed to assess resident use of Virtual, In-Person, or a combination of Both review formats, to elicit their format preferences, and reasons for their preferences. We theorized virtual-preferring residents would endorse areas previously associated with enhanced e-learning outcomes more than in-person peers. Online questionnaires were emailed to current PGY1-PGY5 residents in Canadian radiation oncology programs. Questionnaires examined level of training, typical review format, preferred format, and reasons for format preference. Chi-square tests compared differences in format preference and reasons for preference. 52 respondents were included for analysis; PGY1s were excluded due to limited treatment planning exposure. 76.9% of residents typically review with Both virtual and in-person formats, significantly more than 17.3% who review In-Person (p<0.0001) or 5.8% who review Virtually (p<0.0001). When asked which format they preferred, 44.2% preferred Virtual, 36.5% In-Person, and 19.2% preferred a combination of Both. Preference was significantly greater for Virtual versus Both (p=0.006) and In-Person versus Both (p=0.049). Reasons for preference were thematically grouped, reflecting focus upon Interactivity, Practice, Feedback, Convenience, and Teaching Quality. Significant differences were not found between In-Person and Virtual-preferring respondents in terms of Feedback, Interactivity, or Practice. However, significant within-group differences existed between Convenience versus Teaching Quality (Virtual-preferring: 84.3%>61%, p=0.0198; Both-preferring: 76.7%>40%, p=0.0324; In-person-preferring: 25%<63%, p=0.00214), and between Feedback versus Interactivity (Virtual-preferring: 66.7%>45.4%, p=0.0048; In Person-preferring: 59.7%>37%, p=0.00634). Our results suggest residents review contours and treatment plans with a combination of virtual and in-person formats, more than either format alone, despite low resident preference for this approach. While use of either format appears acceptable to residents, differences in emphasis on convenience with virtual-preferring and teaching quality in residents preferring in-person review suggests that educational priorities may differ between residents. Feedback more than interactivity seems important for residents irrespective of preferred format. Thus, residents and attendings should identify a format that best meets resident's educational needs and priorities. Further research should explore attending preferences. [ABSTRACT FROM AUTHOR]

Purpose: To examine the clinical benefits and toxicities of 223Ra in 2 different age groups of patients with castrate-resistant prostate cancer.Methods and Materials: This was a retrospective study of patients treated with 223Ra in 2 tertiary centers. Patients were divided into 2 different groups based on their age (≥72 years old and <72 years old). Treatment toxicities were graded according to Common Terminology Criteria for Adverse Events version 4.0. Comparison of characteristics and outcome was carried out with the Mann-Whitney test and analysis of overall survival with the log-rank test.Results: In all, 129 patients were treated during the study period. Clinical benefit was similar in both groups. However, a statistically significant higher proportion of patients in the younger group had previously been treated with docetaxel. There was a higher rate of grade 3 anemia in younger patients.Conclusions: In line with other studies, 223Ra was well tolerated with minimum toxicities. The significantly higher rate of grade 3 anemia in younger patients may be due to more cautious patient selection in the elderly population. [ABSTRACT FROM AUTHOR]

Purpose: Organ-confined muscle-invasive bladder cancer is treated with cystectomy or bladder preservation techniques, including radiation therapy. There are currently no biomarkers to inform management decisions and aid patient choice. Previously we showed high levels of MRE11 protein, assessed by immunohistochemistry (IHC), predicted outcome after radiation therapy, but not cystectomy. Therefore, we sought to develop the MRE11 IHC assay for clinical use and define its relationship to clinical outcome in samples from 2 major clinical trials.Methods and Materials: Samples from the BCON and BC2001 randomized controlled trials and a cystectomy cohort were stained using automated IHC methods and scored for MRE11 in 3 centers in the United Kingdom.Results: Despite step-wise creation of scoring cards and standard operating procedures for staining and interpretation, there was poor intercenter scoring agreement (kappa, 0.32; 95% confidence interval, 0.17-0.47). No significant associations between MRE11 scores and cause-specific survival were identified in BCON (n = 132) and BC2001 (n = 221) samples. Reoptimized staining improved agreement between scores from BCON tissue microarrays (n = 116), but MRE11 expression was not prognostic for cause-specific survival.Conclusions: Manual IHC scoring of MRE11 was not validated as a reproducible biomarker of radiation-based bladder preservation success. There is a need for automated quantitative methods or a reassessment of how DNA-damage response relates to clinical outcomes. [ABSTRACT FROM AUTHOR]