AIMS:The objective of this study was to develop a two-year overall survival model for inoperable stage I-III non-small cell lung cancer (NSCLC) patients using routine radiation oncology data over a federated (distributed) learning network and evaluate the potential of decision support for curative versus palliative radiotherapy. METHODS:A federated infrastructure of data extraction, de-identification, standardisation, image analysis, and modelling was installed for seven clinics to obtain clinical and imaging features and survival information for patients treated in 2011-2019. A logistic regression model was trained for the 2011-2016 curative patient cohort and validated for the 2017-2019 cohort. Features were selected with univariate and model-based analysis and optimised using bootstrapping. System performance was assessed by the receiver operating characteristic (ROC) and corresponding area under curve (AUC), C-index, calibration metrics and Kaplan-Meier survival curves, with risk groups defined by model probability quartiles. Decision support was evaluated using a case-control analysis using propensity matching between treatment groups. RESULTS:1655 patient datasets were included. The overall model AUC was 0.68. Fifty-eight percent of patients treated with palliative radiotherapy had a low-to-moderate risk prediction according to the model, with survival times not significantly different (p = 0.87 and 0.061) from patients treated with curative radiotherapy classified as high-risk by the model. When survival was simulated by risk group and model-indicated treatment, there was an estimated 11% increase in survival rate at two years (p < 0.01). CONCLUSION:Federated learning over multiple institution data can be used to develop and validate decision support systems for lung cancer while quantifying the potential impact of their use in practice. This paves the way for personalised medicine, where decisions can be based more closely on individual patient details from routine care.

Purpose/Objective(s) To implement an efficient Prostate SABR program into a regional service without real-time seed-tracking capability utilizing automated template-based planning. Materials/Methods Our regional service uses multileaf collimator linear accelerators which are not equipped to perform real-time seed-tracking prompting the exploration of alternatives to mitigate the risk of tumor motion during treatment. A protocol was developed using EVIQ Guidelines as well as PACE-B and PACE-C clinical trial constraints. A treatment planning template was developed using a treatment planning software with a single 10MV FFF beam to minimize treatment delivery time, minimizing the risk of intra-fraction motion. Using scripting 200 plans were calculated and dosimetric criteria exported without therapist intervention. Plans were analyzed using ideal, minor, or major violation criterion. A Cone Beam Computer Tomography (CBCT) protocol was developed to optimize image quality; without increasing image acquisition time. An Intra-fraction CBCT protocol was developed for post treatment review to assess possible variation during treatment and patient stability. A Surface Guided Radiation Therapy (SGRT) protocol was developed to assist with monitoring during treatment. Results A treatment Planning Template developed using 200 plans achieved clinically acceptable plans over 80% of the time with no intervention. The clinical template met treatment criteria or required only minor changes in 95% of patients. Running the template via script allowed 57% more plans to be assessed for template performance, giving increased confidence that dosimetric results can be consistent without therapist intervention. Treatment delivery quality was assessed using routine Physics Quality Assurance (QA) methods. 30 plans were delivered on an arc check with all plans passing QA with a minimum pass rate of 95% using Gamma Analysis with 2% and 2mm. Treatment delivery time was assessed for 30 plans with an average delivery time of 90 seconds. Use of template-based planning allowed consistent plan quality, improved efficiency, and consistent treatment delivery times. The use of scripting further enhanced efficiency. Data from pre-treatment CBCT’s, Intra-Fraction CBCT and SGRT will allow assessment of patient stability. Conclusion An efficient Prostate SABR program can be successfully implemented in a regional service without real-time seed-tracking. Template-based planning allows shorter planning time frames and more consistent treatment plans and treatment delivery times. Script-based planning allowed more plans to be assessed for template performance, increasing confidence that dosimetric results can be consistent without therapist intervention. The use of Intra-Faction CBCT in conjunction with SGRT will allow verification of patient stability during treatment.

Abstract Introduction Current contouring guidelines for curative radiation therapy for muscle‐invasive bladder cancer (MIBC) recommend margins of 1.5–2.0 cm, applied to the clinical target volume (CTV). This study assessed whether the use of volumetric modulated arc therapy (VMAT), cone beam computed tomography (CBCT) and strict bladder preparation allowed for a reduced planning target volume (PTV) expansion, resulting in lower doses to surrounding organs at risk (OARs). Methods Daily CBCT images for 12 patients (382 scans total) were retrospectively reviewed against four potential PTV margins created on and exported with the reference CT scan. To form the PTVs, three isotropic expansions of 0.5, 1.0 and 1.5 cm were applied to the CTV, as well as an anisotropic expansion of 1.5 cm superiorly and 1.0 cm in all other dimensions. Following treatment completion, the CBCTs were visually assessed to determine the margins encapsulating the bladder. For retrospective planning purposes, the 1.0‐cm and anisotropic margins were compared with the previously recommended margins to determine differences in OAR doses. Results The 0.5‐, 1.0‐ and 1.5‐cm isotropic margins (IM) and the anisotropic margin (ANIM) covered the CTV in 46.1, 96.8, 100 and 100% of CBCTs retrospectively. Doses to OARs were significantly lower for the reduced margin plans for the small bowel, rectum and sigmoid. Conclusion Bladder planning target volumes may be safely reduced. We endorse a PTV margin of 1.0cm anteriorly, posteriorly and inferiorly with 1.0–1.5 cm superiorly for radical whole bladder cases using strict bladder preparation, VMAT and pretreatment CBCTs.

INTRODUCTION:There is significant potential to analyse and model routinely collected data for radiotherapy patients to provide evidence to support clinical decisions, particularly where clinical trials evidence is limited or non-existent. However, in practice there are administrative, ethical, technical, logistical and legislative barriers to having coordinated data analysis platforms across radiation oncology centres. METHODS:A distributed learning network of computer systems is presented, with software tools to extract and report on oncology data and to enable statistical model development. A distributed or federated learning approach keeps data in the local centre, but models are developed from the entire cohort. RESULTS:The feasibility of this approach is demonstrated across six Australian oncology centres, using routinely collected lung cancer data from oncology information systems. The infrastructure was used to validate and develop machine learning for model-based clinical decision support and for one centre to assess patient eligibility criteria for two major lung cancer radiotherapy clinical trials (RTOG-9410, RTOG-0617). External validation of a 2-year overall survival model for non-small cell lung cancer (NSCLC) gave an AUC of 0.65 and C-index of 0.62 across the network. For one centre, 65% of Stage III NSCLC patients did not meet eligibility criteria for either of the two practice-changing clinical trials, and these patients had poorer survival than eligible patients (10.6 m vs. 15.8 m, P = 0.024). CONCLUSION:Population-based studies on routine data are possible using a distributed learning approach. This has the potential for decision support models for patients for whom supporting clinical trial evidence is not applicable.

Aim: To assess a class solution template for volumetric-modulated arc therapy (VMAT) for prostate cancer using plan analysis software. Background: VMAT is a development of intensity-modulated radiotherapy (IMRT) with potential advantages for the delivery of radiotherapy (RT) in prostate cancer. Class solutions are increasingly used for facilitating RT planning. Plan analysis software provides an objective tool for evaluating class solutions. Materials and methods: The class solution for VMAT was based on the current static field IMRT template. The plans of 77 prostate cancer patients were evaluated using a set of in-house plan quality metrics (scores) (PlanIQ (TM), Sun Nuclear Corporation). The metrics compared the class solution for VMAT planning with the IMRT template and the delivered clinical plan (CP). Eight metrics were associated with target coverage and ten with organs-at-risk (OAR). Individual metrics were summed and the combined scores were subjected to non parametric analysis. The low-dose wash for both static IMRT and VMAT plans were evaluated using 40 Gy and 25 Gy isodose volumes. Results: VMAT plans were of equal or better quality than the IMRT template and CP for target coverage (combined score) and OAR combined score. The 40 Gy isodose volume was marginally higher with VMAT than IMRT (4.9%) but lower than CP (-6.6%)(P = 0.0074). The 25 Gy volume was significantly lower with VMAT than both IMRT (-32.7%) and CP (-34.4%)(P<0.00001). Conclusions: Automated VMAT planning for prostate cancer is feasible and the plans are equal to or better than the current IMRT class solution and the delivered clinical plan. Crown Copyright (C) 2018 Published by Elsevier Sp. z o.o. on behalf of Greater Poland Cancer Centre. All rights reserved.

AIM:To develop and apply a clinical incident taxonomy for radiation therapy. BACKGROUND:Capturing clinical incident information that focuses on near-miss events is critical for achieving higher levels of safety and reliability. METHODS AND MATERIALS:A clinical incident taxonomy for radiation therapy was established; coding categories were prescription, consent, simulation, voluming, dosimetry, treatment, bolus, shielding, imaging, quality assurance and coordination of care. The taxonomy was applied to all clinical incidents occurring at three integrated cancer centres for the years 2011-2015. Incidents were managed locally, audited and feedback disseminated to all centres. RESULTS:Across the five years the total incident rate (per 100 courses) was 8.54; the radiotherapy-specific coded rate was 6.71. The rate of true adverse events (unintended treatment and potential patient harm) was 1.06. Adverse events, where no harm was identified, occurred at a rate of 2.76 per 100 courses. Despite workload increases, overall and actual rates both exhibited downward trends over the 5-year period. The taxonomy captured previously unidentified quality assurance failures; centre-specific issues that contributed to variations in incident trends were also identified. CONCLUSIONS:The application of a taxonomy developed for radiation therapy enhances incident investigation and facilitates strategic interventions. The practice appears to be effective in our institution and contributes to the safety culture. The ratio of near miss to actual incidents could serve as a possible measure of incident reporting culture and could be incorporated into large scale incident reporting systems.

Aim: To use plan analysis software to evaluate a class solution for prostate intensity modulated radiotherapy (IMRT) planning. Background: Class solutions for radiotherapy planning are increasingly being considered for streamlining planning. Plan analysis software provides an objective approach to evaluating radiotherapy plans. Materials and methods: Three iterations of a class solution for prostate IMRT planning (T1, T2 and Tfinal) were compared to the clinical plan of 74 prostate patients using radiotherapy plan analysis software (Plan IQ (TM), Sun Nuclear Corporation). A set of institution-specific plan quality metrics (scores) were established, based on best practice guidelines. Results: For CTV coverage, Tfinal was not significantly different to the clinical plan. With the exception of 95% PTV coverage, Tfinal metrics were significantly better than the clinical plan for PTV coverage. In the scoring analysis, mean dose, 95% and 107% isodose coverage scores were similar for all the templates and clinical plan. 100% coverage of the CTV clinical plan was similar to Tfinal but scored higher than T1 and T2. There were no significant differences between Tfinal and the clinical plan for the metrics and scores associated with organs at risk. The total plan score was similar for Tfinal and the clinical plan, although the scores for volume receiving total dose outside the PTV were higher for Tfinal than for the clinical plan(P < 0.0001). Conclusions: The radiotherapy plan analysis software was useful for evaluating a class solution for prostate IMRT planning and provided evidence that the class solution produced clinically acceptable plans for these patients. Crown Copyright (C) 2017 Published by Elsevier Sp. z o.o. on behalf of Greater Poland Cancer Centre. All rights reserved.

INTRODUCTION:Evidence of variations in bladder filling effecting prostate stability and therefore treatment and side-effects is well established with intensity modulated radiation therapy (IMRT). This study aimed to increase bladder volume reproducibility for prostate radiation therapy by implementing a bladder scanning (BS) protocol that could assist patients' bladder filling at computed tomography (CT) simulation and treatment. METHODS:Based on a retrospective review of 524 prostate cancer patients, a bladder volume of 250-350 mL was adopted as 'ideal' for achieving planning dose constraints. A prospective cohort study was conducted to assess the clinical utility of measuring patients' bladder volumes at CT simulation using an ultrasound bladder scanner (Verathon 9400 BladderScan(®)). A revised bladder preparation protocol was utilised by a bladder scan group (BS) and a non-BS group followed the standard departmental bladder preparation protocol. Time and volume data for the BS group (n = 17) were compared with the non-BS group (n = 17). RESULTS:The BS cohort had a CT bladder volume range of 221-588 mL; mean 379 mL, SD 125 mL. The non-BS group had a larger range: 184-757 mL; mean 373 mL, SD 160 mL (P = 0.9171). There was a positive correlation between CT volume and BS volume in the BS group (r = 0.797; P = 0.0002) although BS volumes were smaller: range 160-420 mL; mean 251 mL; SD 91 mL; P < 0.0001). The maximum bladder volume receiving 50 Gy (V50) from the BS group was 46.4%, mean 24.5%. The maximum bladder V50 from the non-BS group was 50.9%, mean 27.3% (P = 0.5178). Treatment data from weekly cone beam CT scans were also compared over 6 weeks. They were assessed as being a pass if bladder and bowel requirements were acceptable. The BS group proceeded to treatment on the basis of a pass 92.7% of the time, whereas the pass rate for non-BS group was 75%; difference 17.7% (P < 0.0001). CONCLUSION:The BS is a useful tool for achieving consistent, appropriately sized bladder volumes in prostate cancer patients.

INTRODUCTION:For patients receiving radiotherapy for locally advance non-small cell lung cancer (NSCLC), the probability of experiencing severe radiation pneumonitis (RP) appears to rise with an increase in radiation received by the lungs. Intensity modulated radiotherapy (IMRT) provides the ability to reduce planned doses to healthy organs at risk (OAR) and can potentially reduce treatment-related side effects. This study reports toxicity outcomes and provides a dosimetric comparison with three-dimensional conformal radiotherapy (3DCRT).METHODS:Thirty curative NSCLC patients received radiotherapy using four-dimensional computed tomography and five-field IMRT. All were assessed for early and late toxicity using common terminology criteria for adverse events. All plans were subsequently re-planned using 3DCRT to the same standard as the clinical plans. Dosimetric parameters for lungs, oesophagus, heart and conformity were recorded for comparison between the two techniques.RESULTS:IMRT plans achieved improved high-dose conformity and reduced OAR doses including lung volumes irradiated to 5-20 Gy. One case each of oesophagitis and erythema (3%) were the only Grade 3 toxicities. Rates of Grade 2 oesophagitis were 40%. No cases of Grade 3 RP were recorded and Grade 2 RP rates were as low as 3%.CONCLUSION:IMRT provides a dosimetric benefit when compared to 3DCRT. While the clinical benefit appears to increase with increasing target size and increasing complexity, IMRT appears preferential to 3DCRT in the treatment of NSCLC.

Imaging for breast cancer comprises multiple options in terms of modalities and protocols that have to be applied in the clinical context by radiologists, referring GPs and medical imaging technicians across a broad patient population.We will discuss the roles of modalities such as mammography (standard 2D and 3D/ DBT), breast ultrasound as well as the suite of interventional options including ultrasound-guided fine needle aspiration/biopsy, core biopsy, vacuum-assisted core biopsy, stereotactic vacuum core (mammotomy), pre-operative hookwire placement and specimen imaging.We will discuss briefly the patient/practitioner expectations of breast MR and the reality.The clinical application of imaging protocols across the screening and diagnostic patient populations, including modality combination and imaging intervals, will be mentioned.Imaging case studies will be presented.Psychosocial aspects of patient care during treatment of breast cancer

Radiation Oncology Practice Standards have been developed over the last 10 years and were published for use in Australia in 2011. Although the majority of the radiation oncology community supports the implementation of the standards, there has been no mechanism for uniform assessment or governance. North Coast Cancer Institute's public radiation oncology service is provided across three main service centres on the north coast of NSW. With a strong focus on quality management, we embraced the opportunity to demonstrate conformity with the Radiation Oncology Practice Standards. The Local Health District's Clinical Governance units were engaged to perform assessments of our conformity with the standards and this was signed off as complete on 16 December 2013. The process of demonstrating conformity with the Radiation Oncology Practice Standards has enhanced the culture of quality in our centres. We have demonstrated that self‐assessment utilising trained auditors is a viable method for centres to demonstrate conformity. National implementation of the Radiation Oncology Practice Standards will benefit individual centres and the broader radiation oncology community to improve the service delivered to our patients.

Step-and-shoot (S&S) intensity-modulated radiotherapy (IMRT) using the XiO treatment planning system (TPS) has been routinely used for patients receiving postprostatectomy radiotherapy (PPRT). After installing the Monaco, a pilot study was undertaken with five patients to compare XiO with Monaco (V2.03) TPS for PPRT with respect to plan quality for S&S as well as volumetric-modulated arc therapy (VMAT). Monaco S&S showed higher mean clinical target volume (CTV) coverage (99.85%) than both XiO S&S (97.98%, P = 0.04) and Monaco VMAT (99.44, P = 0.02). Rectal V60Gy volumes were lower for Monaco S&S compared to XiO (46.36% versus 58.06%, P = 0.001) and Monaco VMAT (46.36% versus 54.66%, P = 0.02). Rectal V60Gy volume was lowest for Monaco S&S and superior to XiO (mean 19.89% versus 31.25%, P = 0.02). Rectal V60Gy volumes were lower for Monaco VMAT compared to XiO (21.09% versus 31.25%, P = 0.02). Other organ-at-risk (OAR) parameters were comparable between TPSs. Compared to XiO S&S, Monaco S&S plans had fewer segments (78.6 versus 116.8 segments, P = 0.02), lower total monitor units (MU) (677.6 MU versus 770.7 MU, P = 0.01), and shorter beam-on times (5.7 min versus 7.6 min, P = 0.03). This pilot study suggests that Monaco S&S improves CTV coverage, OAR doses, and planning and treatment times for PPRT.

Introduction: The performance and limitations of an atlas- based autosegmentation software package (ABAS; Elekta Inc.) was evaluated using male pelvic anatomy as the area of interest. Methods: Contours from 10 prostate patients were selected to create atlases in ABAS. The contoured regions of interest were created manually to align with published guidelines and included the prostate, bladder, rectum, femoral heads and external patient contour. Twenty-four clinically treated prostate patients were auto-contoured using a randomised selection of two, four, six, eight or ten atlases. The concordance between the manually drawn and computer-generated contours were evaluated statistically using Pearson's product-moment correlation coefficient (r) and clinically in a validated qualitative evaluation. In the latter evaluation, six radiation therapists classified the degree of agreement for each structure using seven clinically appropriate categories. Results: The ABAS software generated clinically acceptable contours for the bladder, rectum, femoral heads and external patient contour. For these structures, ABAS-generated volumes were highly correlated with 'as treated' volumes, manually drawn; for four atlases, for example, bladder r = 0.988 (P < 0.001), rectum r = 0.739 (P < 0.001) and left femoral head r = 0.560 (P < 0.001). Poorest results were seen for the prostate (r = 0.401, P < 0.05) (four atlases); however this was attributed to the comparison prostate volume being contoured on magnetic resonance imaging (MRI) rather than computed tomography (CT) data. For all structures, increasing the number of atlases did not consistently improve accuracy. Conclusions: ABAS-generated contours are clinically useful for a range of structures in the male pelvis. Clinically appropriate volumes were created, but editing of some contours was inevitably required. The ideal number of atlases to improve generated automatic contours is yet to be determined.

INTRODUCTION:There is substantial interest in implementation of image-guided intensity-modulated radiotherapy (IG-IMRT) in the post-prostatectomy setting. We describe our implementation of IG-IMRT, and examine how often published organ-at-risk (OAR) constraints were met. Furthermore, we evaluate the incidence of acute genitourinary and gastrointestinal toxicities when patients were treated according to our protocol.METHODS:Patients were eligible if they received post-prostatectomy radiotherapy (PPRT). Planning data were collected prospectively, and toxicity assessments were collected before, during and after treatment.RESULTS:Seventy-five eligible patients received either 64 Gy (19%) or 66 Gy (81%) in a single phase to the prostate bed. Suggested rectal dose-constraints of V40Gy < 60% and V60Gy < 40% were met in 64 (85%) and 75 (100%) patients, respectively. IMRT-specific rectal dose-constraints of V40Gy < 35% and V65Gy < 17% were achieved in 5 (7%) and 57 (76%) of patients. Bladder dose-constraint (V50Gy < 50%) was met in 58 (77%) patients. Two patients (3%) experienced new grade 3 genitourinary toxicity and one patient (1%) experienced new grade 3 gastroinestinal toxicity. All grade 3 toxicities had improved by 3-month review. Overall deterioration in urinary and gastrointestinal symptoms occurred in 33 (44%) and 35 (47%) of patients respectively.CONCLUSIONS:We report on our implementation of PPRT which takes into account nationally adopted guidelines, with a margin reduction supported by use of daily image guidance. Non-IMRT OAR constraints were met in most cases. IMRT-specific constraints were less often achieved despite margin reductions, suggesting the need for review of guidelines. Severe toxicity was rare, and most patients did not experience deterioration in urinary or bowel function attributable to radiotherapy.

Poster: RANZCR ASM 2011 / R-0028 / Use Of Monte Carlo-Based Dose Calculations and Biological Cost Functions Leads to Improved Plan Quality in Post-Prostatectomy Image-Guided Intensity Modulated Radiation Therapy (IG-IMRT) by: B. Chua , A. Rankine, K. Davidson, S. Greenham, A. Kovendy, T. Shakespeare; Coffs Harbour/AU