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The medical necessity of stereotactic radiosurgery (SRS) is nonuniform across insurance policies. The American Society for Radiation Oncology (ASTRO) created a model policy based on the consensus of the radiation oncology community to communicate medically necessary indications for SRS. We compared the current insurance policies for SRS with those of the ASTRO model policy.We identified 58 insurance payers and 3 national benefits managers with SRS policies. Among these, 7 insurance payers were excluded for policies that were not reviewed after 2015 and for not detailing individual medically necessary indications. For each of the indications listed in ASTRO's model policy, we determined the proportion of payers that considered SRS medically necessary. We compared these proportions for national versus regional payers and policies updated in the last 12 months versus those updated less often using Fisher exact and χAll insurance policies reviewed considered SRS as medically necessary for brain metastases, medically refractory trigeminal neuralgia, and arteriovenous malformations. Compared with national payers, regional payers were less likely to deem other schwannomas, and a boost for large cranial or spinal lesions medically necessary (P.05). The indication with the lowest coverage was medically refractory movement disorders (44.4%), followed by medically refractory epilepsy (33.3%). However, policies that were updated within the last year were more likely to deem medical necessity for epilepsy, movement disorders, hemangioblastoma, pineal gland tumors, and other schwannomas.Significant discrepancy remains among insurance policies for several indications in ASTRO's model policy for SRS; however, national payers and those with recent policy updates have a greater concordance with the ASTRO model policy.

Purpose This study aimed to evaluate the feasibility of using a single-institution, knowledge-based planning (KBP) model as a dosimetric plan quality control (QC) for multi-institutional clinical trials. The efficacy of this QC tool was retrospectively evaluated using a subset of plans submitted to Radiation Therapy Oncology Group (RTOG) study 0617. Methods and Materials A single KBP model was created using commercially available software (RapidPlan; Varian Medical Systems, Palo Alto, CA) and data from 106 patients with non-small cell lung cancer who were treated at a single institution. All plans had prescriptions that ranged from 60 Gy in 30 fractions to 74 Gy in 37 fractions and followed the planning guidelines from RTOG 0617. Two sets of optimization objectives were created to produce different trade-offs using the single KBP model predictions: one prioritizing target coverage and a second prioritizing lung sparing (LS) while allowing an acceptable variation in target coverage. Three institutions submitted a high volume of clinical plans to RTOG 0617 and provided data on 25 patients, which were replanned using both sets of optimization objectives. Model-generated, dose-volume histogram predictions were used to identify patients who exceeded the lung clinical target volume (CTV) V20Gy >37% and would benefit from the LS objectives. Overall plan quality differences between KBP-generated plans and clinical plans were evaluated at RTOG 0617–defined dosimetric endpoints. Results Target coverage and organ at risk sparing was significantly improved for most KBP-generated plans compared with those from clinical trial data. The KBP model using prioritized target coverage objectives reduced heart Dmean and V40Gy by 2.1 Gy and 5.2%, respectively. Similarly, using LS objectives reduced the lung CTV Dmean and V20Gy by 2.0 Gy and 2.9%, respectively. The KBP predictions correctly identified all patients with lung CTV V20Gy > 37% (5 of 25 patients) and significantly reduced the dose to the lung CTV by applying the LS optimization objectives. Conclusions A single-institution KBP model can be applied as a QC tool for multi-institutional clinical trials to improve overall plan quality and provide decision-support to determine the need for anatomy-based dosimetric trade-offs.

Purpose Clinical concern remains regarding the relationship between consecutive (QD) versus nonconsecutive (QoD) lung stereotactic body radiation therapy (SBRT) treatment schedules and outcomes for clinical stage I non-small cell lung cancer (NSCLC). We examined a multi-institutional series of patients receiving 5-fraction lung SBRT to compare the local failure rates and overall survival between patients receiving QD versus QoD treatment. Methods and materials Lung SBRT databases from 2 high-volume institutions were combined, and patients receiving 5-fraction SBRT for a solitary stage I NSCLC were identified. QD treatment was defined as completing SBRT in ≤7 days, whereas QoD treatment was defined as completing treatment in >7 days. To control for patient characteristics between the 2 institutions, a 1:1 propensity-matched analysis was performed. Multivariable logistic regression was performed to identify variables independently associated with local failure, and Cox proportional hazards modeling to identify variables independently associated with increased mortality. Results From 2005 through 2016, 245 clinical stage I NSCLC patients receiving 5-fraction SBRT were identified. A total of 117 (47.8%) patients received QD treatment and 128 (52.2%) patients received QoD treatment. On propensity-matched analysis, no association was seen between QD treatment and local failure (odds ratio [OR] for QD treatment, 0.48; 95% confidence interval [CI], 0.12-1.99; P = .5). On multivariable logistic regression, central tumors were independently associated with increased likelihood of local recurrence (OR, 5.2; 95% CI, 1.11-24.2; P = .04). Kaplan-Meier analysis identified no difference in median overall survival between QD versus QoD treatments (38.0 vs 38.0 months, log-rank P = .7), respectively. QD treatment was not associated with an increased mortality hazard (hazard ratio, 1.08; 95% CI, 0.67-1.75; P = .75). Conclusions This analysis demonstrated no association between QD versus QoD treatment scheduling and local control or overall survival for early-stage NSCLC.

Purpose This is a review of our 2-year experience with the first single-gantry proton therapy (PT) system. Methods and materials All patients were consented to participate on an institutional review board–approved prospective patient registry between December 2013 and December 2015. PT was delivered in a single-room facility using a synchrocyclotron with proton beam energy of 250 MeV. The dataset was interrogated for demographics, diagnosis, treatment modality, and clinical trial involvement. Cases were classified as simple or complex based on fields used and immobilization. The volume of photon patients treated in our department was collected between January 2011 and December 2015 to evaluate the impact of PT on our photon patient volume. Results A total of 278 patients were treated with PT, including 228 (82%) adults and 50 (18%) pediatric cases. PT patients traveled a mean distance of 83.3 miles compared with 47.4 miles for photon patients queried in 2015. Rationale for treatment included reirradiation (20%), involvement in prospective clinical trial (14%), and proximity to critical structures to maximally spare organs at risk (66%). Forty patients were enrolled on 5 adult and 3 pediatric prospective clinical trials. The most common histologies treated were glioma (27%) and non-small cell lung cancer (18%) in adults, and medulloblastoma (22%) and low-grade glioma (24%) in pediatric patients. Prostate cancer composed 6% of PT. Complex cases composed 45% of our volume. Our photon patient volume increased yearly between 2011 and 2015, with 2780 patients completing photon treatment in 2011 and 3385 patients in 2015. PT composed 4% of overall patients treated with external beam radiation. Conclusions The installation of our single-gantry proton facility has expanded the treatment options within our cancer center, helping to increase the number of patients we see. Patients travel from twice as far away to receive this treatment, many for typical PT indications such as pediatrics or to participate in prospective clinical trials.

Magnetic resonance imaging (MRI) guided radiation therapy is reported for the first time in a patient with an implantable cardioverter defibrillator (ICD) and cardiac fibroma in the left ventricle. Stereotactic body radiation therapy was delivered in 5 fractions at a dose of 700 cGy/fraction using a 0.35 T MRI–linear accelerator with real-time tumor tracking and beam gating. The average treatment time per fraction was 12.13 minutes, including gating dead time and gantry rotation, and the average duty cycle was 56.8%. Lessons learned included the need for MRI safety workflows that address the ICD and are tailored to the radiation oncology environment, selection of a suitable tracking target to ensure satisfactory duty cycle, and the presence of null band artifacts within the tracking target caused by ferrous components in the ICD.

Purpose Cardiac radiation is associated with cardiotoxicity in patients with thoracic and breast malignancies. We conducted a prospective study using cine magnetic resonance imaging (MRI) scans to evaluate heart motion. We hypothesized that cine MRI could be used to define population-based cardiac planning organ-at-risk volumes (PRV). Methods and Materials A total of 16 real-time acquisitions were obtained per subject on a 1.5 Tesla MRI (Philips Ingenia). Planar cine MRI was performed in 4 sequential sagittal and coronal planes at free-breathing (FB) and deep-inspiratory breath hold (DIBH). In-plane cardiac motion was assessed using a scale-invariant feature transformation–based algorithm. Subject-specific pixel motion ranges were defined in anteroposterior (AP), left-right (LR), and superoinferior (SI) planes. Averages of the 98% and 67% of the maximum ranges of pixel displacement were defined by subject, then averaged across the cohort to calculate PRV expansions at FB and DIBH. Results Data from 20 subjects with a total of 3120 image frames collected per subject in coronal and sagittal planes at DIBH and FB, and 62,400 total frames were analyzed. Cohort averages of 98% of the maximum cardiac motion ranges comprised margin expansions of 12.5 ± 1.1 mm SI, 5.8 ± 1.2 mm AP, and 6.6 ± 1.0 mm LR at FB and 6.7 ± 1.5 mm SI, 4.7 ± 1.3 mm AP, and 5.3 ± 1.3 mm LR at DIBH. Margins for 67% of the maximum range comprised 7.7 ± 0.7 mm SI, 3.2 ± 0.6 mm AP, and 3.7 ± 0.6 mm LR at FB and 4.1 ± 0.9 mm SI, 2.7 ± 0.8 mm AP, and 3.2 ± 0.8 mm LR at DIBH. Subsequently, these margins were simplified to form PRVs for treatment planning. Conclusions We implemented scale-invariant feature transformation-based motion tracking for analysis of the cardiac cine MRI scans to quantify motion and create cohort-based cardiac PRVs to improve cardioprotection in breast and thoracic radiation.

Purpose The objective of this study was to create a workflow for the automation and standardization of treatment plan generation and evaluation using an application programming interface (API) to access data from a commercial treatment planning system (Varian Medical Systems, Inc, Palo Alto, CA). Methods and materials The automation workflow begins with converting electronic patient-specific physician treatment planning orders that specify demographics, simulation instructions, and dosimetric objectives for targets and organs at risk into XML files. These XML files are used to generate standard contour names, beam, and patient-specific intensity modulated radiation therapy (IMRT) optimization templates to be executed in a commercial treatment planning system (TPS) by the user. A set of computer programs have been developed to provide quality control (QC) reports that verify demographic information in the TPS against the treatment planning orders, ensure the existence and proper naming of organs at risk, and generate patient-specific plan evaluation reports that provide real-time feedback on the concordance of an active treatment plan to the physician-specified treatment planning goals. Results A workflow for lung IMRT was chosen as a test scenario. Contour, beam, and patient-specific IMRT optimization templates were automatically generated from the physician treatment planning orders and loaded into the planning system. The QC reports were developed for lung IMRT, including the option of patient-specific modifications to the standard templates. The API QC reporting includes a dynamic program that runs in parallel to the TPS during the planning process, providing real-time feedback as to whether physician-specified treatment plan parameters have improved or worsened from previous iterations. Conclusions User-created computer programs to access information in the TPS database by means of a commercial TPS API enable automation and standardization of treatment plan generation and evaluation.

Introduction In 2014, the NRG Oncology Group initiated the first National Cancer Institute-sponsored, phase 1 clinical trial of stereotactic body radiation therapy (SBRT) for the treatment of multiple metastases in multiple organ sites (BR001; NCT02206334). The primary endpoint is to test the safety of SBRT for the treatment of 2 to 4 multiple lesions in several anatomic sites in a multi-institutional setting. Because of the technical challenges inherent to treating multiple lesions as their spatial separation decreases, we present the technical requirements for NRG-BR001 and the rationale for their selection. Methods and materials Patients with controlled primary tumors of breast, non-small cell lung, or prostate are eligible if they have 2 to 4 metastases distributed among 7 extracranial anatomic locations throughout the body. Prescription and organ-at-risk doses were determined by expert consensus. Credentialing requirements include (1) irradiation of the Imaging and Radiation Oncology Core phantom with SBRT, (2) submitting image guided radiation therapy case studies, and (3) planning the benchmark. Guidelines for navigating challenging planning cases including assessing composite dose are discussed. Results Dosimetric planning to multiple lesions receiving differing doses (45-50 Gy) and fractionation (3-5) while irradiating the same organs at risk is discussed, particularly for metastases in close proximity (≤5 cm). The benchmark case was selected to demonstrate the planning tradeoffs required to satisfy protocol requirements for 2 nearby lesions. Examples of passing benchmark plans exhibited a large variability in plan conformity. Discussion NRG-BR001 was developed using expert consensus on multiple issues from the dose fractionation regimen to the minimum image guided radiation therapy guidelines. Credentialing was tied to the task rather than the anatomic site to reduce its burden. Every effort was made to include a variety of delivery methods to reflect current SBRT technology. Although some simplifications were adopted, the successful completion of this trial will inform future designs of both national and institutional trials and would allow immediate clinical adoption of SBRT trials for oligometastases.