Keole, Sameer R.

PURPOSE: Quality payment programs aim to adjust payments on the basis of quality and cost; however, few quality metrics exist in radiation oncology. This study evaluates and predicts the top spenders (TS) after radiation therapy (RT). MATERIALS AND METHODS: Patient characteristics, cancer details, treatments, toxicity, and survival data were collected for patients treated with RT at Mayo Clinic from 2007 to 2016. Standardized costs were obtained and adjusted for inflation. TSs were identified as those with greater than 93rd percentile costs (≥ $120,812). Prediction models were developed to predict TSs using training and validation sets using information available at consultation, after RT, and at last follow-up. RESULTS: A total of 15,131 patients were included and 1,065 TSs identified. Mean cost overall was $55,290 (median, $39,996) for all patients. Prediction models 1, 2, and 3 had concordance statistics of 0.83 to 0.83, 0.85 to 0.85, and 0.87 to 0.88, respectively in training and validation, indicating excellent prediction of TSs. Factors that were most predictive of TSs included stage N/A and stage 4 ( v stage 0; odds ratio [OR], 18.23 and 8.44, respectively; P < .001); hematologic, upper GI, skin and lung cancers ( v breast; OR, 11.45, 7.69, 3.81, and 2.43, respectively; P < .01); immunotherapy, surgery, and chemotherapy use (OR, 4.36, 2.51, and 1.61, respectively; P < .01); hospitalizations within 90 days of RT (OR, 2.26; P < .01); or death during the episode (OR, 1.56; P < .01). CONCLUSION: This is the first study of its kind to predict with high accuracy the highest spenders in radiation oncology. These patients may benefit from pre-emptive management to mitigate costs, or may require exclusion or adjustment from quality payment programs.

6633 Background: Quality based payment programs in medicine are currently being introduced nationally, aimed to improve care and reduce cost. This study aimed to evaluate the top spenders (TS) after cancer diagnosis and predict TS at two separate time points using predictive analytics. Methods: Patient characteristics, cancer details, treatments, adverse events, and outcomes were collected for patients treated for cancer at Mayo Clinic from 2007 - 2017. Standardized costs over a 2 year period after first treatment were obtained from the Mayo Clinic Cost Data Warehouse with Medicare reimbursements assigned to all services and adjusted to the 2017 GDP Implicit Price Deflator for inflation. TS were identified as those with greater than 93rd percentile costs (≥$113,158) due to a sharp rise in cost at that level. Descriptive statistics and univariate analysis were used for comparison. A prediction model with a training (80%) and validation set (20%) using multivariate selection was used to predict TS and was repeated using information available at 1) the time of consultation and 2) at last follow-up. Results: A total of 80,385 patients were included and 5,626 TS were identified. Mean cost (25th, 75th percentile) overall was $44,953 ($16,776, $51,889). Prediction models at time 1 and 2 had ROC AUC statistics of 0.82 and 0.89 in training and 0.82 and 0.88 in the validation indicating good prediction of high costs. Factors most predictive of TS included need for blood transfusions within 90 days of treatment (OR 5.3), bone marrow transplant (OR 4.0), mild liver disease (OR 3.5), hemiplegia (OR 3.4), weight loss > 10% within 90 days of treatment (OR 3.3), upper GI cancer (OR 3.0), ‘other’ cancer type (OR 2.8), immunotherapy use (OR 2.7), and hospitalizations within 90 days (OR 2.4), all p < 0.001, among others. The largest costs were due to hospital services in the TS and non-TS groups, mean costs $114,258 and $13,185 respectively. Conclusions: This is the first study to predict with high accuracy the top spenders in Oncology. Patient comorbidities and toxicities were among the strongest predictors of high costs, along with certain treatments (bone marrow transplant and immunotherapy). Our findings suggest that quality payment programs should adjust for comorbidities, and that reducing toxicity may be an effective method at reducing costs.

145 Background: Palliative radiation treatment (pRT) is used for symptomatic bone metastases (mets). Several fractionation schedules show equal efficacy for pain relief, and ASTRO’s Choosing Wisely recommends 8Gy x1, 4Gy x5, or 3Gy x10. This study aims to investigate the cost implications of pRT for bone mets. Methods: Patients (Pts) treated with pRT for bone mets at Mayo Clinic from 2007 - 2016 were included in this study. Costs for all services were subdivided into RT and total costs at 30 & 90 days (30D & 90D). Standardized costs were obtained from the Mayo Clinic Cost Data Warehouse and Medicare reimbursements were assigned to all services with cost to charge adjustments and 2017 GDP Implicit Price Deflator for inflation. Cost means were compared via the Kruskal-Wallis test. Results: 538 pts were treated with pRT, 124 receiving 8Gy x1, 204 receiving 4Gy x5, and 210 receiving 3Gy x10. Pts with breast and prostate cancer were most likely to be treated with 3Gy x10 and pts with GI and lung cancer were most likely to be treated with 8Gy x1. RT costs at 30D were $1,497, $1,891, and $1,982 (p=0.03) and RT costs at 90D were $2,602, $2,753, and $3,032 (p=0.08) for initial RT regimens of 8Gy x1, 4Gy x5, and 3Gy x10. Total costs of care at 30D were similar from $15,969 - 17,687 (p=0.6) and total costs at 90D were similar from $22,361 - 23,219 (p=0.7) between arms. A total of 23%, 28%, and 39% of pts were alive 2 years following pRT from each arm (p=0.07). Conclusions: This is the first study of its kind to analyze actual treatment costs for the three most common pRT regimens in bone mets. Single fraction RT was most used for pts with poor prognoses and was associated with lower RT costs at 30D, but similar RT costs at 90D, possibly due to retreatment. RT choice had no impact on overall costs of care at 30D or 90D. pRT remains of high value, representing only 11-13% of total costs.[Table: see text]

e16555 Background: The ProtecT trial underscores the importance of treatment in men with prostate cancer and life expectancies > 10 years and the validity of radiation therapy (RT). RT can be given with photons or protons (PT). To address the controversy of which is better, clinical outcomes of photon-based intensity modulated RT (IMRT) and PT cohorts from 2 institutions were directly compared. Methods: Under respective IRB approvals, data from 2 cohorts were analyzed. The first was 301 men treated with ultrasound image guided IMRT from 2000-05 to 75.6 Gy in 42 fractions. The second was 1214 men treated with fiducial image guided PT from 2006-10 to 78 CGE in 39 fractions. Median age and followup were 74 y and 7.2 y for IMRT and 66 y and 5.6 y for PT. Hormone therapy (ADT) was used with IMRT and PT, respectively, in 3% and 7% of low-risk patients, 25% and 9.9% of intermediate-risk, and 91% and 57.8% of high-risk. Comparative endpoints were age-stratified 5-year (5Y) survival (OS), ≥ grade 3 gastrointestinal (GI) and urologic (GU) toxicity, and 5Y freedom from biochemical progression (FFBP). Results: There was a lower prevalence of GI (1.3% vs 0.1%, p = 0.0065) and GU (4.3% vs 0.1%, p < 0.0001) toxicity at last follow-up in the PT group. In the IMRT and PT cohorts, OS rates were 90.8% and 88.7% in men ≥75 (p = 0.4083). In men < 75, OS rates were 91.6% and 97.5% in the IMRT and PT low-risk patients (p = 0.003), 92.1% and 95.5% in the IMRT and PT intermediate-risk (p = 0.0535), and 92.0% and 90.0% (p = 0.4975) in the IMRT and PT high-risk. In the IMRT and PT cohorts, respectively, FFBP rates were 92.2% and 98.9% for low-risk patients (p < 0.0001), 87.3% and 94.5% for intermediate-risk patients(p = 0.0226), and 80.3% and 74.4% for high-risk patients (p = 0.5154). Conclusions: In this retrospective comparison of outcomes in cohorts of men treated with IMRT and PT for prostate cancer, FFBP rates were better with PT for men with low- and intermediate-risk disease and similar in men with high-risk disease despite longer and more frequent use of ADT in the IMRT cohort. This study underscores the difficulty of comparing retrospective series, with differences noted in age, RT dose, and ADT use between cohorts. However, the magnitude of improvement with PT is intriguing and warrants prospective testing.

PurposeThe purpose of this study was to develop a fast method for proton range quality assurance (QA) using a dual step wedge and two‐dimensional (2D) scintillator and to evaluate the robustness, sensitivity, and long‐term reproducibility of this method.MethodsAn in‐house customized dual step wedge and a 2D scintillator were developed to measure proton ranges. Proton beams with homogenous fluence were delivered through wedge, and the images captured by the scintillator were used to calculate the proton ranges by a simple trigonometric method. The range measurements of 97 energies, comprising all clinically available synchrotron energies at our facility (ranges varying from 4 to 32 cm) were repeated ten times in all four gantry rooms for range baseline values. They were then used for evaluating room‐to‐room range consistencies. The robustness to setup uncertainty was evaluated by measuring ranges with ±2 mm setup deviations in the x, y, and z directions. The long‐term reproducibility was evaluated by 1 month of daily range measurements by this method.ResultsRanges of all 97 energies were measured in less than 10 minutes including setup time. The reproducibility in a single day and daily over 1 month is within 0.1 and 0.15 mm, respectively. The method was very robust to setup uncertainty, with measured range consistencies within 0.15 mm for ±2 mm couch shifts. The method was also sensitive enough for validating range consistencies among gantry rooms and for detecting small range variations.ConclusionsThe new method of using a dual step wedge and scintillator for proton range QA was efficient, highly reproducible, and robust. This method of proton range QA was highly feasible and appealing from a workflow point of view.

PurposeTo accurately model the beam delivery time (BDT) for a synchrotron‐based proton spot scanning system using experimentally determined beam parameters.MethodsA model to simulate the proton spot delivery sequences was constructed, and BDT was calculated by summing times for layer switch, spot switch, and spot delivery. Test plans were designed to isolate and quantify the relevant beam parameters in the operation cycle of the proton beam therapy delivery system. These parameters included the layer switch time, magnet preparation and verification time, average beam scanning speeds in x‐ and y‐directions, proton spill rate, and maximum charge and maximum extraction time for each spill. The experimentally determined parameters, as well as the nominal values initially provided by the vendor, served as inputs to the model to predict BDTs for 602 clinical proton beam deliveries. The calculated BDTs (TBDT) were compared with the BDTs recorded in the treatment delivery log files (TLog): ∆t = TLog−TBDT.ResultsThe experimentally determined average layer switch time for all 97 energies was 1.91 s (ranging from 1.9 to 2.0 s for beam energies from 71.3 to 228.8 MeV), average magnet preparation and verification time was 1.93 ms, the average scanning speeds were 5.9 m/s in x‐direction and 19.3 m/s in y‐direction, the proton spill rate was 8.7 MU/s, and the maximum proton charge available for one acceleration is 2.0 ± 0.4 nC. Some of the measured parameters differed from the nominal values provided by the vendor. The calculated BDTs using experimentally determined parameters matched the recorded BDTs of 602 beam deliveries (∆t = −0.49 ± 1.44 s), which were significantly more accurate than BDTs calculated using nominal timing parameters (∆t = −7.48 ± 6.97 s).ConclusionsAn accurate model for BDT prediction was achieved by using the experimentally determined proton beam therapy delivery parameters, which may be useful in modeling the interplay effect and patient throughput. The model may provide guidance on how to effectively reduce BDT and may be used to identifying deteriorating machine performance.

PurposeTo implement and evaluate a novel and fast method for proton range verification by using a planar scintillator and step wedge.MethodsA homogenous proton pencil beam plan with 35 energies was designed and delivered to a 2D flat scintillator with a step wedge. The measurement was repeated 15 times (3 different days, 5 times per day). The scintillator image was smoothed, the Bragg peak and distal fall off regions were fitted by an analytical equation, and the proton range was calculated using simple trigonometry. The accuracy of this method was verified by comparing the measured ranges to those obtained using an ionization chamber and a scanning water tank, the gold standard. The reproducibility was evaluated by comparing the ranges over 15 repeated measurements. The sensitivity was evaluated by delivering to same beam to the system with a film inserted under the wedge.ResultsThe range accuracy of all 35 proton energies measured over 3 days was within 0.2 mm. The reproducibility in 15 repeated measurements for all 35 proton ranges was ±0.045 mm. The sensitivity to range variation is 0.1 mm for the worst case. This efficient procedure permits measurement of 35 proton ranges in less than 3 min. The automated data processing produces results immediately. The setup of this system took less than 5 min. The time saving by this new method is about two orders of magnitude when compared with the time for water tank range measurements.ConclusionsA novel method using a scintillator with a step wedge to measure the proton range was implemented and evaluated. This novel method is fast and sensitive, and the proton range measured by this method was accurate and highly reproducible.

48 Background: The purpose of this study is to identify differences in toxicity, quality of life (QOL), and dosimetric endpoints among patients with low-risk prostate adenocarcinoma treated with either standard fractionation or hypofractionation proton-beam therapy. Methods: We analyzed the results of the first 75 patients treated in our phase III trial comparing 38Gy relative biological effectiveness (RBE) in 5 fractions (fx) (n = 46) vs. 79.2Gy (RBE) in 44 fx. (n = 29). All patients had low-risk prostate cancer and were treated with proton radiation using fiducial markers and daily image guidance. We evaluated American Urological Association (AUA) Symptom Index, adverse events (AEs), and Expanded Prostate Index Composite (EPIC) domains at pretreatment and 3, 6, 12, 18, 24, 36 and 48 months. Doses to the prostate were selected based on similar long term effects to normal tissue based on an α/β = 3.5 for an EQD2 of 76Gy. Results: The median follow-up was 36 months for both groups; 23 (30%) patients reached a follow-up of 48 months. We observed a small difference in AUA score (3.2 vs. 8.6, p = 0.002) at 1-year favoring the 79.2Gy arm. AUA scores were not statistically different at 18 months and after. Similarly, EPIC Urinary symptoms favored the 79.2Gy arm at 1 year (92.3 vs. 84.5, p = 0.009) and 18 months (92.3 vs. 85.3, p = 0.03); bother scores were not significantly different at any other time points. G2 or higher GU toxicity was similar between arms (p = 0.8). No differences in EPIC Bowel symptoms, EPIC Sexual symptoms, or bowel G2 or higher toxicities were seen. One death was observed in the 38Gy arm due to an unrelated case of multiple myeloma. The bladder V80 (79.2Gy arm, p = 0.04) and V39 (38Gy arm, p = 0.05) were predictive for G2 or higher GU AE. There was no association observed between rectal dose and G2 or higher rectal toxicity. Conclusions: Patients treated in the hypofractionated and standard arms tolerated treatment well. A small and temporary difference in the GU domain was seen favoring the standard arm. As predicted long term effects on the GU domain and bowel were similar for both arms, suggesting that the α/β is similar to 3.5 for long term effects. Clinical trial information: 01230866.

Purpose: To present the most updated American College of Radiology consensus guidelines formed from an expert panel on treatment of locally advanced, high-risk prostate cancer Methods: The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment. Results: The panel summarized the most recent and relevant literature on the topic and voted on 4 clinical variants illustrating the appropriate management of locally advanced, high-risk cancer. Numerical rating and commentary reflecting the panel consensus was given for each treatment approach in each variant. Conclusions: Aggressive local approaches including surgery followed by adjuvant XRT, beam combined with androgen deprivation therapy, and beam combined with brachytherapy have resulted in unpresented success in locally advanced, high-risk prostate cancer. By combining most recent medical literature and expert opinion, this guideline can aid clinicians in the appropriate integration of available therapeutic modalities.