Improved survival in cervical cancer patients receiving care at National Cancer Institute-designated cancer centers.

BACKGROUND: Locally advanced cervical cancer (CC) remains lethal in the United States. We investigate the effect of receiving care at an National Cancer Institute-designated cancer center (NCICC) on survival. METHODS: Data for women diagnosed with CC from 2004 to 2016 who received radiation treatment were extracted from the California Cancer Registry (n = 4250). Cox proportional hazards regression models assessed whether (1) receiving care at NCICCs was associated with risk of CC-specific death, (2) this association remained after multivariable adjustment for age, race/ethnicity, and insurance status, and (3) this association was explained by receipt of guideline-concordant treatment. RESULTS: Median age was 50 years (interquartile range [IQR] 41-61 years), with median follow-up of 2.7 years (IQR 1.3-6.0 years). One-third of patients were seen at an NCICC, and 29% died of CC. The hazard of CC-specific death was reduced by 20% for those receiving care at NCICCs compared with patients receiving care elsewhere (HR = .80; 95% CI, 0.70-0.90). Adjustment for guideline-concordant treatment and other covariates minimally attenuated the association to 0.83 (95% CI, 0.74-0.95), suggesting that the survival advantage associated with care at NCICCs may not be due to receipt of guideline-concordant treatment. CONCLUSIONS: This study demonstrates survival benefit for patients receiving care at NCICCs compared with those receiving care elsewhere that is not explained by differences in guideline-concordant care. Structural, organizational, or provider characteristics and differences in patients receiving care at centers with and without NCI designation could explain observed associations. Further understanding of these factors will promote equality across oncology care facilities and survival equity for patients with CC.

Volumetric de-escalation and improved acute toxicity with proton craniospinal irradiation using a vertebral body-sparing technique.

PURPOSE: In growing children, craniospinal irradiation (CSI) has historically treated the entire vertebral body (VB) to avoid potential long-term spinal abnormalities. Vertebral body-sparing proton craniospinal irradiation (VBSpCSI) is a technique that spares the majority of the VB from significant irradiation, and long-term safety outcomes have been reported previously. This retrospective study reviews the acute toxicity profile of children treated with VBSpCSI in a cohort comparison with photon-based craniospinal radiotherapy (3DCRT). METHODS: Thirty-eight pediatric CSI patients treated between 2008 and 2018 were retrospectively evaluated for treatment-related toxicity. Acute toxicity outcomes and acute hematologic profiles were compared according to treatment modality, either VBSpCSI or 3DCRT. Statistical analysis was performed using Fisher's exact test for toxicity. RESULTS: Twenty-five patients received VBSpCSI and 13 patients received photon CSI. Mean patient age at treatment was 7.5 years (range 2-16). The cohorts were well matched with respect to gender, age, and CSI dose. Patients receiving VBSpCSI had lower rates of grade 2+ gastrointestinal (GI) toxicity (24% vs. 76.5%, p = .005), grade 2+ nausea (24% vs. 61.5%, p = .035), and any-grade esophagitis (0% vs. 38%, p = .0026). Patients treated with VBSpCSI had lower red blood cell transfusion rates (21.7% vs. 60%, p = .049) and grade 4+ lymphopenia (33.3% vs. 77.8%, p = .046). CONCLUSIONS: VBSpCSI in children is a volumetric de-escalation from traditional volumes, which irradiate the entire VB to full or intermediate doses. In our study, VBSpCSI was associated with lower rates of acute GI and hematologic toxicities. Long-term growth outcomes and disease control outcomes are needed for this technique.

Outcomes of Black men with prostate cancer treated with radiation therapy in the Veterans Health Administration.

BACKGROUND: Population-based studies demonstrate that Black men in the United States have an increased risk of death from prostate cancer. Determinants of racial disparities are multifactorial, including socioeconomic and biologic factors. METHODS: The authors conducted a pooled analysis of patients derived from 152 centers within the Veterans Health Administration. The cohort included men who had nonmetastatic prostate diagnosed between 2001 and 2015 and received definitive radiation therapy. The primary endpoint was prostate cancer-specific mortality (PCSM). Secondary endpoints included all-cause mortality (ACM) and the time from a prostate-specific antigen level ≥4 ng/mL to biopsy and radiation therapy. A Cox regression model was performed to adjust for differences between clinical parameters. RESULTS: Among the 31,131 patients included in the cohort, 9584 (30.8%) were Black. The 10-year cumulative incidence of death from prostate cancer was lower in Black men compared with White men (4.0% vs 4.8%; P = .004). In a competing risk model, Black race was associated with a decreased risk of PCSM (subdistribution hazard ratio, 0.79; 95% CI, 0.69-0.92; P = .002). Similarly, the 10-year cumulative incidence of death from any cause was lower in Black men (27.6% vs 31.8%; P < .001). In multivariable analysis, Black men had a 10% decreased risk of ACM (hazard ratio, 0.90; 95% CI, 0.85-0.95; P < .001). CONCLUSIONS: The current results indicate relatively lower PCSM and ACM among Black men who were included in a large Veterans Health Administration cohort and received radiation therapy as primary treatment for nonmetastatic prostate cancer. There is an ongoing need to continue to understand and mitigate the factors associated with disparities in health care outcomes.

A review of patient questions from physicist-patient consults.

PURPOSE: To provide insight into the types of questions asked to medical physicists by patients during one-on-one physicist-patient consults at one institution. MATERIALS AND METHODS: Medical physicists trained in patient communication techniques met with patients to provide an overview of the treatment planning and delivery processes, discuss the patient's treatment plan, and answer any technical questions. From August 2016 to December 2019, 152 physicist-patient consults were conducted. In the initial months of the study (August 2016-December 2017), following each physicist-patient consult, all patient questions were documented by the physicists. For the remaining time period (January 2018-December 2019), any newly encountered questions were periodically added to the list. The questions were compiled into a comprehensive list and organized into categories. RESULTS: There were a total of 88 unique patient questions. These questions fit into four topical categories. Fifty-four questions (61.4%) were in the "Treatment Planning and Delivery Questions" category, 15 questions (17.1%) were in the "General Radiation Questions or Concerns" category, 13 questions (14.8%) were in the "Safety and Quality Assurance Questions" category, and 6 questions (6.8%) were in the "Medical Questions" category. Overall, patients were primarily concerned about how radiation works, the treatment planning and delivery processes, and what is being done to keep them safe throughout their treatment. CONCLUSION: Physicist-patient consults provided an opportunity to address the technical aspects of radiation therapy with patients in greater detail. The fact that patient questions could be conveniently grouped into only four topical categories indicates that it may be straightforward for other medical physicists to prepare for effectively addressing technical questions during physicist-patient consults.

Association Between African American Race and Clinical Outcomes in Men Treated for Low-Risk Prostate Cancer With Active Surveillance.

Importance: There is concern that African American men with low-risk prostate cancer may harbor more aggressive disease than non-Hispanic White men. Therefore, it is unclear whether active surveillance is a safe option for African American men. Objective: To compare clinical outcomes of African American and non-Hispanic White men with low-risk prostate cancer managed with active surveillance. Design, Setting, and Participants: Retrospective cohort study in the US Veterans Health Administration Health Care System of African American and non-Hispanic White men diagnosed with low-risk prostate cancer between January 1, 2001, and December 31, 2015, and managed with active surveillance. The date of final follow-up was March 31, 2020. Exposures: Active surveillance was defined as no definitive treatment within the first year of diagnosis and at least 1 additional surveillance biopsy. Main Outcomes and Measures: Progression to at least intermediate-risk, definitive treatment, metastasis, prostate cancer-specific mortality, and all-cause mortality. Results: The cohort included 8726 men, including 2280 African American men (26.1%) (median age, 63.2 years) and 6446 non-Hispanic White men (73.9%) (median age, 65.5 years), and the median follow-up was 7.6 years (interquartile range, 5.7-9.9; range, 0.2-19.2). Among African American men and non-Hispanic White men, respectively, the 10-year cumulative incidence of disease progression was 59.9% vs 48.3% (difference, 11.6% [95% CI, 9.2% to 13.9%); P < .001); of receipt of definitive treatment, 54.8% vs 41.4% (difference, 13.4% [95% CI, 11.0% to 15.7%]; P < .001); of metastasis, 1.5% vs 1.4% (difference, 0.1% [95% CI, -0.4% to 0.6%]; P = .49); of prostate cancer-specific mortality, 1.1% vs 1.0% (difference, 0.1% [95% CI, -0.4% to 0.6%]; P = .82); and of all-cause mortality, 22.4% vs 23.5% (difference, 1.1% [95% CI, -0.9% to 3.1%]; P = 0.09). Conclusions and Relevance: In this retrospective cohort study of men with low-risk prostate cancer followed up for a median of 7.6 years, African American men, compared with non-Hispanic White men, had a statistically significant increased 10-year cumulative incidence of disease progression and definitive treatment, but not metastasis or prostate cancer-specific mortality. Longer-term follow-up is needed to better assess the mortality risk.

Three-month posttreatment prostate-specific antigen level as a biomarker of treatment response in patients with intermediate-risk or high-risk prostate cancer treated with androgen deprivation therapy and radiotherapy.

BACKGROUND: Prostate-specific antigen (PSA) measurement after definitive radiotherapy (RT) and androgen deprivation therapy for localized prostate cancer has been proposed as an early prognostic biomarker. In the current study, the authors investigated the association between 3-month post-RT PSA level and biochemical progression-free survival (bPFS), prostate cancer-specific survival (PCSS), and overall survival (OS). METHODS: A total of 5783 patients with intermediate-risk or high-risk localized prostate cancer who were diagnosed between 2000 and 2015 and treated with RT and androgen deprivation therapy were identified from Veterans Affairs data. Patients were divided into groups based on 3-month post-RT PSA values: <0.10 ng/mL, 0.10 to 0.49 ng/mL, and ≥0.50 ng/mL. The effect of the 3-month PSA group on bPFS, PCSS, and OS was evaluated in multivariable Cox models adjusting for potential confounders. RESULTS: There were 2651 patients with intermediate-risk and 3132 with high-risk disease; approximately 11% had a 3-month PSA level of ≥0.50 ng/mL. A higher 3-month PSA level was found to be strongly associated with each outcome; compared with patients in the group with a 3-month PSA value <0.10 ng/mL, the authors noted greater hazards for the patients with a 3-month PSA value ≥0.50 ng/mL (hazard ratio for bPFS: 5.23; PCSS: 3.97; and OS: 1.50 [P<.001 for all]) and the patients with a 3-month PSA value of 0.10 to 0.49 ng/mL (hazard ratio for bPFS: 2.41 [P<.001]; PCSS: 2.29 [P<.001]; and OS: 1.21 [P = .003]). When analyzed separately, the 3-month PSA level was found to be predictive of OS in the high-risk group (P<.001) but not the intermediate-risk group (P = .21). CONCLUSIONS: The 3-month post-RT PSA level appears to be a strong prognostic biomarker for bPFS, PCSS, and OS in patients with intermediate-risk and high-risk prostate cancer, particularly those with high-risk disease. The 3-month PSA measurement may augment clinical decision making and holds promise as a potential surrogate endpoint in clinical trials. Cancer 2018;124:2939-47. © 2018 American Cancer Society.

Underutilization of brachytherapy and disparities in survival for patients with cervical cancer in California.

PURPOSE: The treatment for locally advanced cervical cancer is external beam radiation (EBRT), concurrent chemotherapy, and brachytherapy (BT). We investigated demographic and socioeconomic factors that influence trends in BT utilization and disparities in survival. METHODS: Using the California Cancer Registry, cervical cancer patients FIGO IB2-IVA from 2004 to 2014 were identified. We collected tumor, demographic and socioeconomic (SES) factors. We used multivariable logistic regression analysis to determine predictors of use of BT. Using Cox proportional hazards, we examined the impact of BT vs EBRT boost on cause specific (CSS) and overall survival (OS). RESULTS: We identified 4783 patients with FIGO stage 11% IB2; 32% II, 54% III, 3% IVA. Nearly half (45%) of patients were treated with BT, 18% were treated with a EBRT boost, and 37% had no boost. Stage II and III were more likely to be treated with BT (p = 0.002 and p = 0.0168) vs Stage IB2. As patients aged, the use of BT decreased. Using multivariate analysis, BT impacted CCS (HR 1.16, p = 0.0330) and OS (HR 1.14, p = 0.0333). Worse CSS was observed for black patients (p = 0.0002), low SES (p = 0.0263), stage III and IVA (p < 0.0001. Black patients, low and middle SES had worse OS, (p = 0.0003). CONCLUSIONS: The utilization of BT in locally advanced cervical cancer was low at 45%, with a decrease in CSS and OS. Black patients and those in low SES had worse CSS. As we strive for outcome improvement in cervical cancer, we need to target increasing access and disparities for quality and value.

A program to train medical physicists for direct patient care responsibilities.

OBJECTIVES: To develop a training program designed to meet the specific needs of medical physicists as they transition into a clinical role with direct patient care responsibilities. MATERIALS AND METHODS: The training program was designed in collaboration with the faculty at the UC San Diego School of Medicine and incorporates training techniques that have been shown to be effective in improving communication skills. The program emphasizes experiential, practice-based learning over didactic presentations. RESULTS: The training program is comprised of 5 components: 1) a 1-day Clinician-Patient Communication Workshop run by the UC San Diego School of Medicine, 2) Communication Strategies for Radiation Oncology, which consists of two, 2-hour sessions designed to provide trainees with patient communication skills that are specific to patient interactions in radiation oncology, 3) Simulated Patient Interactions, in which trainees perform mock physicist-patient consults with trained patient actors, 4) Faculty-Observed Patient Consults, and 5) a Case-Based Treatment Toxicity Course. A competency assessment mechanism was also developed to provide a clear set of objectives and to guide trainer feedback. [Correction added after first online publication on November 7, 2018: The phrase ", which consists of two, 2-hour" was added above.] CONCLUSIONS: The training program that we have developed incorporates an array of established education techniques and provides a comprehensive, accessible, means of improving medical physicists' patient communication skills.

Characterizing cardiac contractile motion for noninvasive radioablation of ventricular tachycardia.

Background: Respiratory motion management strategies are used to minimize the effects of breathing on the precision of stereotactic ablative radiotherapy for ventricular tachycardia, but the extent of cardiac contractile motion of the human heart has not been systematically explored. Objective: We aim to assess the magnitude of cardiac contractile motion between different directions and locations in the heart. Methods: Patients with intracardiac leads or valves who underwent 4-dimensional cardiac computed tomography (CT) prior to a catheter ablation procedure for atrial or ventricular arrhythmias at 2 medical centers were studied retrospectively. The displacement of transvenous right atrial appendage, right ventricular (RV) implantable cardioverter-defibrillator, coronary sinus lead tips, and prosthetic cardiac devices across the cardiac cycle were measured in orthogonal 3-dimensional views on a maximal-intensity projection CT reconstruction. Results: A total of 31 preablation cardiac 4-dimensional cardiac CT scans were analyzed. The LV lead tip had significantly greater motion compared with the RV lead in the anterior-posterior direction (6.0 ± 2.2 mm vs 3.8 ± 1.7 mm; P = .01) and superior-inferior direction (4.4 ± 2.9 mm vs 3.5 ± 2.0 mm; P = .049). The prosthetic aortic valves had the least movement of all fiducials, specifically compared with the RV lead tip in the left-right direction (3.2 ± 1.2 mm vs 6.1 ± 3.8 mm, P = .04) and the LV lead tip in the anterior-posterior direction (3.8 ± 1.7 mm vs 6.0 ± 2.2 mm, P = .03). Conclusion: The degree of cardiac contractile motion varies significantly (1 mm to 15.2 mm) across different locations in the heart. The effect of contractile motion on the precision of radiotherapy should be assessed on a patient-specific basis.

Combination of fractionated irradiation with anti-VEGF expressing vaccinia virus therapy enhances tumor control by simultaneous radiosensitization of tumor associated endothelium.

Oncolytic viruses are currently in clinical trials for a variety of tumors, including high grade gliomas. A characteristic feature of high grade gliomas is their high vascularity and treatment approaches targeting tumor endothelium are under investigation, including bevacizumab. The aim of this study was to improve oncolytic viral therapy by combining it with ionizing radiation and to radiosensitize tumor vasculature through a viral encoded anti-angiogenic payload. Here, we show how vaccinia virus-mediated expression of a single-chain antibody targeting VEGF resulted in radiosensitization of the tumor-associated vasculature. Cell culture experiments demonstrated that purified vaccinia virus encoded antibody targeting VEGF reversed VEGF-induced radioresistance specifically in endothelial cells but not tumor cells. In a subcutaneous model of U-87 glioma, systemically administered oncolytic vaccinia virus expressing anti-VEGF antibody (GLV-1h164) in combination with fractionated irradiation resulted in enhanced tumor growth inhibition when compared to nonanti-VEGF expressing oncolytic virus (GLV-1h68) and irradiation. Irradiation of tumor xenografts resulted in an increase in VACV replication of both GLV-1h68 and GLV-1h164. However, GLV-1h164 in combination with irradiation resulted in a drastic decrease in intratumoral VEGF levels and tumor vessel numbers in comparison to GLV-1h68 and irradiation. These findings demonstrate the incorporation of an oncolytic virus expressing an anti-VEGF antibody (GLV-1h164) into a fractionated radiation scheme to target tumor cells by enhanced VACV replication in irradiated tumors as well as to radiosensitize tumor endothelium which results in enhanced efficacy of combination therapy of human glioma xenografts.

The effect of treatment time in locally advanced cervical cancer in the era of concurrent chemoradiotherapy.

BACKGROUND: This study sought to determine if treatment time impacts pelvic failure (PF), distant failure (DF), or disease-specific mortality (DSM) in patients undergoing concurrent chemoradiotherapy (CCRT). METHODS: A retrospective review was performed of 113 consecutive eligible patients with stage IB2 to IIIB cervical cancer. All patients received whole-pelvis radiation with concurrent chemotherapy and consolidative intracavitary brachytherapy (BT) to the cervix, followed by an external beam parametrial boost when appropriate. The effect of treatment time on PF, DF, and DSM was examined with univariate and multivariate analyses. Characteristics of patients with and without treatment prolongation were compared to explore reasons for treatment prolongation. RESULTS: The median time to completion of BT was 60 days, and the median time to complete all RT was 68 days. The 3-year cumulative incidence of PF, DF, and DSM were 18%, 23%, and 26%, respectively. On multivariate analysis, time to completion of BT >56 days was associated with increased PF (hazard ratio, 3.8; 95% confidence interval, 1.2-16; P = .02). The 3-year PF for >56 days versus ≤56 days was 26% versus 9% (P = .04). Treatment time was not associated with DF or DSM. Treatment prolongation was found to be associated with delay in starting BT and higher incidence of acute grade 3/4 toxicities. CONCLUSIONS: In the setting of CCRT, treatment time >56 days is detrimental to pelvic control but is not associated with an increase in DF or DSM. To maximize pelvic control, we recommend completing BT in 8 weeks or less.

Neurocognitive assessment following whole brain radiation therapy and radiosurgery for patients with cerebral metastases.

The treatment of metastatic brain lesions remains a central challenge in oncology. Because most chemotherapeutic agents do not effectively cross the blood-brain barrier, it is widely accepted that radiation remains the primary modality of treatment. The mode by which radiation should be delivered has, however, become a source of intense controversy in recent years. The controversy involves whether patients with a limited number of brain metastases should undergo whole brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS) delivered only to the radiographically visible tumours. Survival is comparable for patients treated with either modality. Instead, the controversy involves the neurocognitive function (NCF) of radiating cerebrum that appeared radiographically normal relative to effects of the growth from micro-metastatic foci. A fundamental question in this debate involves quantifying the effect of WBRT in patients with cerebral metastasis. To disentangle the effects of WBRT on neurocognition from the effects inherent to the underlying disease, we analysed the results from randomised controlled studies of prophylactic cranial irradiation in oncology patients as well as studies where patients with limited cerebral metastasis were randomised to SRS versus SRS+WBRT. In aggregate, these results suggest deleterious effects of WBRT in select neurocognitive domains. However, there are insufficient data to resolve the controversy of upfront WBRT versus SRS in the management of patients with limited cerebral metastases.

Outcomes for patients with cervical cancer treated with extended-field intensity-modulated radiation therapy and concurrent cisplatin.

OBJECTIVE: To evaluate disease outcomes and toxicity in patients with cervical cancer treated with extended-field intensity-modulated radiotherapy. MATERIALS AND METHODS: We included all patients treated with extended-field intensity-modulated radiotherapy and concurrent weekly cisplatin from 2003 to 2010 at 2 institutions. Overall survival and disease-free survival were estimated using Kaplan-Meier method. Locoregional failure (LRF), distant failure, and competing mortality were calculated using cumulative incidence functions. Acute and late toxicity were graded using Common Terminology Criteria for Adverse Events (CTCAE) and Radiation Therapy Oncology Group late radiation morbidity scoring criteria, respectively. RESULTS: The study included 21 patients, 14 and 20 of which had positive para-aortic and pelvic nodes, respectively. The median follow-up was 22 months. Eighteen-month overall survival and disease-free survival were 59.7% (95% confidence interval [CI], 41.2%-86.4%) and 42.9% (95% CI, 26.2%-70.2%). Eighteen-month cumulative incidences of LRF, distant failure, and competing mortality were 9.5% (95% CI, 1.5-26.8%), 42.9% (95% CI, 21.3-62.9%), and 4.8% (95% CI, 0.3-20.2%), respectively. Eighteen-month cumulative incidences of late grade 3 or higher-grade genitourinary and gastrointestinal toxicity were 4.8% (95% CI, 0.2%-20.3%) and 0%, respectively. CONCLUSIONS: Intensity-modulated extended-field radiotherapy was associated with low rates of late toxicity and LRF. High rates of distant failure indicate that this group of patients could benefit from intensified systemic therapy.

Feasibility study on dosimetry verification of volumetric-modulated arc therapy-based total marrow irradiation.

The purpose of this study was to develop dosimetry verification procedures for volumetric-modulated arc therapy (VMAT)-based total marrow irradiation (TMI). The VMAT based TMI plans were generated for three patients: one child and two adults. The planning target volume (PTV) was defined as bony skeleton, from head to mid-femur, with a 3 mm margin. The plan strategy similar to published studies was adopted. The PTV was divided into head and neck, chest, and pelvic regions, with separate plans each of which is composed of 2-3 arcs/fields. Multiple isocenters were evenly distributed along the patient's axial direction. The focus of this study is to establish a dosimetry quality assurance procedure involving both two-dimensional (2D) and three-dimensional (3D) volumetric verifications, which is desirable for a large PTV treated with multiple isocenters. The 2D dose verification was performed with film for gamma evaluation and absolute point dose was measured with ion chamber, with attention to the junction between neighboring plans regarding hot/cold spots. The 3D volumetric dose verification used commercial dose reconstruction software to reconstruct dose from electronic portal imaging devices (EPID) images. The gamma evaluation criteria in both 2D and 3D verification were 5% absolute point dose difference and 3 mm of distance to agreement. With film dosimetry, the overall average gamma passing rate was 98.2% and absolute dose difference was 3.9% in junction areas among the test patients; with volumetric portal dosimetry, the corresponding numbers were 90.7% and 2.4%. A dosimetry verification procedure involving both 2D and 3D was developed for VMAT-based TMI. The initial results are encouraging and warrant further investigation in clinical trials.

Quality and Safety Considerations in Image Guided Radiation Therapy: An ASTRO Safety White Paper Update.

PURPOSE: This updated report on image guided radiation therapy (IGRT) is part of a series of consensus-based white papers previously published by the American Society for Radiation Oncology addressing patient safety. Since the first white papers were published, IGRT technology and procedures have progressed significantly such that these procedures are now more commonly used. The use of IGRT has now extended beyond high-precision treatments, such as stereotactic radiosurgery and stereotactic body radiation therapy, and into routine clinical practice for many treatment techniques and anatomic sites. Therefore, quality and patient safety considerations for these techniques remain an important area of focus. METHODS AND MATERIALS: The American Society for Radiation Oncology convened an interdisciplinary task force to assess the original IGRT white paper and update content where appropriate. Recommendations were created using a consensus-building methodology, and task force members indicated their level of agreement based on a 5-point Likert scale from "strongly agree" to "strongly disagree." A prespecified threshold of ≥75% of raters who selected "strongly agree" or "agree" indicated consensus. SUMMARY: This IGRT white paper builds on the previous version and uses other guidance documents to primarily focus on processes related to quality and safety. IGRT requires an interdisciplinary team-based approach, staffed by appropriately trained specialists, as well as significant personnel resources, specialized technology, and implementation time. A thorough feasibility analysis of resources is required to achieve the clinical and technical goals and should be discussed with all personnel before undertaking new imaging techniques. A comprehensive quality-assurance program must be developed, using established guidance, to ensure IGRT is performed in a safe and effective manner. As IGRT technologies continue to improve or emerge, existing practice guidelines should be reviewed or updated regularly according to the latest American Association of Physicists in Medicine Task Group reports or guidelines. Patient safety in the application of IGRT is everyone's responsibility, and professional organizations, regulators, vendors, and end-users must demonstrate a clear commitment to working together to ensure the highest levels of safety.

Successful Noninvasive 12-Lead ECG Mapping-Guided Radiotherapy of Inaccessible Ventricular Tachycardia Substrate Due to Mechanical Valves.

In patients presenting with refractory ventricular tachycardia (VT) and aortic and mitral mechanical prosthetic valves, traditional catheter ablation is challenging. We describe a case in which a novel noninvasive computational electrocardiogram mapping algorithm localized VT sources originating from substrate near the mechanical valves, in which stereotactic ablative radiotherapy eliminated VT in 1.5-year follow-up. (Level of Difficulty: Advanced.).

Examining the Effect of Direct Patient Care for Medical Physicists: A Randomized Prospective Phase III Trial.

PURPOSE: Our purpose was to investigate the effect of physicist-patient consults on patient anxiety and patient satisfaction with a randomized prospective phase III clinical trial. METHODS AND MATERIALS: Sixty-six patients were randomly assigned to the physics direct patient care (PDPC) arm or the control arm of the trial. Patients assigned to the PDPC arm received 2 physicist-patient consults to educate them on the technical aspects of their radiation therapy, while patients assigned to the control arm received the standard of care (ie, standard radiation therapy workflow without any additional physicist-patient consults). Questionnaires were administered to all patients at 4 time points (after enrollment, after the simulation, after the first treatment, and after the last treatment) to assess anxiety and satisfaction. RESULTS: The decrease in anxiety for the PDPC arm, compared with the control arm, was statistically significant at the first treatment (P = .027) time point. The increase in technical satisfaction for the PDPC arm, compared with the control arm, was statistically significant at the simulation (P = .005), first treatment (P < .001), and last treatment (P = .002) time points. The increase in overall satisfaction for the PDPC arm, compared with the control arm, was statistically significant at the first treatment (P = .014) and last treatment (P = .001) time points. CONCLUSIONS: Physicist-patient consults improved the patient experience by decreasing anxiety and increasing satisfaction. Future work is needed to modify current radiation oncology workflows and medical physics responsibilities to allow all patients to benefit from this advancement in patient care.

Liver motion during cone beam computed tomography guided stereotactic body radiation therapy.

PURPOSE: Understanding motion characteristics of liver such as, interfractional and intrafractional motion variability, difference in motion within different locations in the organ, and their complex relationship with the breathing cycles are particularly important for image-guided liver SBRT. The purpose of this study was to investigate such motion characteristics based on fiducial markers tracked with the x-ray projections of the CBCT scans, taken immediately prior to the treatments. METHODS: Twenty liver SBRT patients were analyzed. Each patient had three fiducial markers (2 × 5-mm gold) percutaneously implanted around the gross tumor. The prescription ranged from 2 to 8 fractions per patient. The CBCT projections data for each fraction (∼650 projections∕scan), for each patient, were analyzed and the 2D positions of the markers were extracted using an in-house algorithm. In total, >55 000 x-ray projections were analyzed from 85 CBCT scans. From the 2D extracted positions, a 3D motion trajectory of the markers was constructed, from each CBCT scans, resulting in left-right (LR), anterior-posterior (AP), and cranio-caudal (CC) location information of the markers with >55 000 data points. The authors then analyzed the interfraction and intrafraction liver motion variability, within different locations in the organ, and as a function of the breathing cycle. The authors also compared the motion characteristics against the planning 4DCT and the RPM™ (Varian Medical Systems, Palo Alto, CA) breathing traces. Variations in the appropriate gating window (defined as the percent of the maximum range at which 50% of the marker positions are contained), between fractions were calculated as well. RESULTS: The range of motion for the 20 patients were 3.0 ± 2.0 mm, 5.1 ± 3.1 mm, and 17.9 ± 5.1 mm in the planning 4DCT, and 2.8 ± 1.6 mm, 5.3 ± 3.1 mm, and 16.5 ± 5.7 mm in the treatment CBCT, for LR, AP, and CC directions, respectively. The range of respiratory period was 3.9 ± 0.7 and 4.2 ± 0.8 s during the 4DCT simulation and the CBCT scans, respectively. The authors found that breathing-induced AP and CC motions are highly correlated. That is, all markers moved cranially also moved posteriorly and vice versa, irrespective of the location. The LR motion had a more variable relationship with the AP∕CC motions, and appeared random with respect to the location. That is, when the markers moved toward cranial-posterior direction, 58% of the markers moved to the patient-right, 22% of the markers moved to the patient-left, and 20% of the markers had minimal∕none motion. The absolute difference in the motion magnitude between the markers, in different locations within the liver, had a positive correlation with the absolute distance between the markers (R(2) = 0.69, linear-fit). The interfractional gating window varied significantly for some patients, with the largest having 29.4%-56.4% range between fractions. CONCLUSIONS: This study analyzed the liver motion characteristics of 20 patients undergoing SBRT. A large variation in motion was observed, interfractionally and intrafractionally, and that as the distance between the markers increased, the difference in the absolute range of motion also increased. This suggests that marker(s) in closest proximity to the target be used.

Impact of age on treatment response in men with prostate cancer treated with radiotherapy.

Objective: To analyse the effect of age at diagnosis on clinical outcomes of localized prostate cancer (PCa) treated with radiation therapy. Subjects and methods: We identified 12 784 patients with intermediate- or high-risk localized PCa treated with radiation therapy (RT) and neoadjuvant androgen deprivation therapy (ADT) between 2000 and 2015 from nationwide Veterans Affairs data. Patients were grouped into three age categories (≤59, 60-69, and ≥70 years old). Outcomes included immediate PSA response (3-month post-RT PSA and 2-year PSA nadir, grouped into <0.10 ng/ml, 0.10-0.49 ng/ml, and ≥0.50 ng/ml), biochemical recurrence, and PCa-specific mortality. Multivariable regression models included ordinal logistic regression for short-term PSA outcomes, Cox regression for biochemical recurrence, and Fine-Gray competing risks regression for PCa-specific mortality. Results: A total of 2136 patients (17%) were ≤59 years old at diagnosis, 6107 (48%) were 60-69 years old, and 4541 (36%) were ≥70 years old. Median follow-up was 6.3 years. Younger age was associated with greater odds of higher 3-month PSA group (≤59 vs. ≥70: adjusted odds ratio [aOR] 1.90, 95% CI 1.64-2.20; p < 0.001) and higher 2-year PSA nadir group (≤59 vs. ≥70: aOR 1.89, 95% CI 1.62-2.19, p < 0.001). Younger age was associated with greater risk of biochemical recurrence (≤59 vs. ≥70: adjusted hazard ratio 1.45, 95% CI 1.26-1.67, p < 0.001) but not PCa-specific mortality (p = 0.16). Conclusion: In a large nationwide sample of US veterans treated with ADT and RT for localized PCa, younger age was associated with inferior short-term PSA response and higher risk of biochemical recurrence.