Assessment of Optimizers and their Performance in Autosegmenting Lung Tumors.

Purpose: Optimizers are widely utilized across various domains to enhance desired outcomes by either maximizing or minimizing objective functions. In the context of deep learning, they help to minimize the loss function and improve model's performance. This study aims to evaluate the accuracy of different optimizers employed for autosegmentation of non-small cell lung cancer (NSCLC) target volumes on thoracic computed tomography images utilized in oncology. Materials and Methods: The study utilized 112 patients, comprising 92 patients from "The Cancer Imaging Archive" (TCIA) and 20 of our local clinical patients, to evaluate the efficacy of various optimizers. The gross tumor volume was selected as the foreground mask for training and testing the models. Of the 92 TCIA patients, 57 were used for training and validation, and the remaining 35 for testing using nnU-Net. The performance of the final model was further evaluated on the 20 local clinical patient datasets. Six different optimizers, namely AdaDelta, AdaGrad, Adam, NAdam, RMSprop, and stochastic gradient descent (SGD), were investigated. To assess the agreement between the predicted volume and the ground truth, several metrics including Dice similarity coefficient (DSC), Jaccard index, sensitivity, precision, Hausdorff distance (HD), 95th percentile Hausdorff distance (HD95), and average symmetric surface distance (ASSD) were utilized. Results: The DSC values for AdaDelta, AdaGrad, Adam, NAdam, RMSprop, and SGD were 0.75, 0.84, 0.85, 0.84, 0.83, and 0.81, respectively, for the TCIA test data. However, when the model trained on TCIA datasets was applied to the clinical datasets, the DSC, HD, HD95, and ASSD metrics showed a statistically significant decrease in performance compared to the TCIA test datasets, indicating the presence of image and/or mask heterogeneity between the data sources. Conclusion: The choice of optimizer in deep learning is a critical factor that can significantly impact the performance of autosegmentation models. However, it is worth noting that the behavior of optimizers may vary when applied to new clinical datasets, which can lead to changes in models' performance. Therefore, selecting the appropriate optimizer for a specific task is essential to ensure optimal performance and generalizability of the model to different datasets.

Autosegmentation of lung computed tomography datasets using deep learning U-Net architecture.

Aim: Current radiotherapy treatment techniques require a large amount of imaging data for treatment planning which demand significant clinician's time to segment target volume and organs at risk (OARs). In this study, we propose to use U-net-based architecture to segment OARs commonly encountered in lung cancer radiotherapy. Materials and Methods: Four U-Net OAR models were generated and trained on 20 lung cancer patients' computed tomography (CT) datasets, with each trained for 100 epochs. The model was tested for each OAR, including the right lung, left lung, heart, and spinal cord. Dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to assess the agreement between the predicted contour and ground truth. Results: The highest of the average DSC among the test patients for the left lung and the right lung was 0.96 ± 0.03 and 0.94 ± 0.06, respectively, and 0.88 ± 0.04 for heart, and 0.76 ± 0.07 for the spinal cord. The HD for these corresponding DSCs was 3.51 ± 0.85, 4.06 ± 1.12, 4.09 ± 0.85, and 2.76 ± 0.52 mm for left lung, right lung, heart, and spinal cord, respectively. Conclusion: The autosegmented regions predicted by right and left lung models matched well with the manual contours. However, in a few cases, the heart model struggled to outline the boundary precisely. The spinal cord model had the lowest DSC, which may be due to its small size. This is an ongoing study aimed to assist radiation oncologists in segmenting the OARs with minimal effort.

Investigation of Computed Tomography Numbers on Multiple Imaging Systems using Single and Multislice Methods.

Aim: The aim of this study is to determine the variation in Hounsfield values with single and multi-slice methods using in-house software on fan-beam computed tomography (FCT), linear accelerator (linac) cone-beam computed tomography (CBCT), and Icon-CBCT datasets acquired using Gammex and advanced electron density (AED) phantoms. Materials and Methods: The AED phantom was scanned on a Toshiba computed tomography (CT) scanner, five linac-based CBCT X-ray volumetric imaging systems, and Leksell Gamma Knife Icon. The variation between single and multi-slice methods was assessed by comparing scans acquired using Gammex and AED phantoms. The variation in Hounsfield units (HUs) between seven different clinical protocols was assessed using the AED phantom. A CIRS Model 605 Radiosurgery Head Phantom (TED) phantom was scanned on all three imaging systems to assess the target dosimetric changes due to HU variation. An in-house software was developed in MATLAB to assess the HU statistics and the trend along the longitudinal axis. Results: The FCT dataset showed a minimal variation (central slice ± 3 HU) in HU values along the long axis. A similar trend was also observed between the studied clinical protocols acquired on FCT. Variation among multiple linac CBCTs was insignificant. In the case of the water insert, a maximum HU variation of -7.23 ± 68.67 was observed for Linac 1 towards the inferior end of the phantom. All five linacs appeared to have a similar trend in terms of HU variation from the proximal to the distal end of the phantom, with a few outliers for Linac 5. Among three imaging modalities, the maximum variation was observed in gamma knife CBCTs, whereas FCT showed no appreciable deviation from the central value. In terms of dosimetric comparison, the mean dose in CT and Linac CBCT scans differed by <0.5 Gy, whereas at least a 1 Gy difference was observed between CT and gamma knife CBCT. Conclusion: This study shows a minimal variation with FCT between single, volume-based, and multislice methods, and hence the current approach of determining the CT-electron density curve based on a single-slice method would be sufficient for producing a HU calibrations curve for treatment planning. However, CBCTs acquired on linac, and in particular, gamma knife systems, show noticeable variations along the long axis, which is likely to affect the dose calculations performed on CBCTs. It is highly recommended to assess the Hounsfield values on multiple slices before using the HU curve for dose calculations.

Comparison of whole breast dosimetry techniques - From 3DCRT to VMAT and the impact on heart and surrounding tissues.

INTRODUCTION: Various techniques for whole breast radiation therapy (WBRT) have been reported to increase dose to contralateral tissues. Heart dose is of critical importance as there is no apparent dose threshold below which there is no risk. The aim of this study was to compare planning techniques for WBRT that achieves the best target dosimetry and lowest organ at risk (OAR) dose. METHODS: Thirty early-stage whole breast patient datasets, 15 each left- and right-sided cases, were retrospectively selected. Five techniques were generated for each data set: three-dimensional conformal radiation therapy (3DCRT), hybrid intensity modulated radiation therapy (HYI), hybrid volumetric modulated arc therapy (VMAT) - (HYV), reduced arc VMAT - bowtie (BT), and BT flattening filter free (FFF) - (BTFFF). Plan goals and OARs were evaluated and compared between techniques. RESULTS: BT had the highest median conformity index (CI) values (0.82, IQR: 0.80-0.85 left and 0.83, IQR 0.80-0.86 right). BT recorded lower mean heart doses (median value 1.19Gy, IQR: 0.90-1.55), and BTFFF recorded lower heart V2.5 Gy , V5 Gy ; median 3.96% (IQR: 2.90-6.80) and 0.90% (IQR: 0.50-1.50) respectively for left-sided patients. There was a statistically significant difference in all ipsilateral lung measures, (p < 0.001) with BTFFF producing significantly lower doses across all measures: mean, V5 Gy , V10 Gy and V20 Gy . CONCLUSION: Overall BT and BTFFF techniques produced lower OAR doses and equivalent PTV coverage for WBRT. BT and BTFFF techniques increased contralateral lung and breast doses; however, these were within prescribed tolerances and comparable to results published in the literature.

Automatic Detection and Tracking of Marker Seeds Implanted in Prostate Cancer Patients using a Deep Learning Algorithm.

PURPOSE: Fiducial marker seeds are often used as a surrogate to identify and track the positioning of prostate volume in the treatment of prostate cancer. Tracking the movement of prostate seeds aids in minimizing the prescription dose spillage outside the target volume to reduce normal tissue complications. In this study, You Only Look Once (YOLO) v2™ (MathWorks™) convolutional neural network was employed to train ground truth datasets and develop a program in MATLAB that can visualize and detect the seeds on projection images obtained from kilovoltage (kV) X-ray volume imaging (XVI) panel (Elekta™). METHODS: As a proof of concept, a wax phantom containing three gold marker seeds was imaged, and kV XVI seed images were labeled and used as ground truth to train the model. The projection images were corrected for any panel shift using flex map data. Upon successful testing, labeled marker seeds and projection images of three patients were used to train a model to detect fiducial marker seeds. A software program was developed to display the projection images in real-time and predict the seeds using YOLO v2 and determine the centers of the marker seeds on each image. RESULTS: The fiducial marker seeds were successfully detected in 98% of images from all gantry angles; the variation in the position of the seed center was within ± 1 mm. The percentage difference between the ground truth and the detected seeds was within 3%. CONCLUSION: Our study shows that deep learning can be used to detect fiducial marker seeds in kV images in real time. This is an ongoing study, and work is underway to extend it to other sites for tracking moving structures with minimal effort.

Partial breast irradiation versus whole breast radiotherapy for early breast cancer.

BACKGROUND: Breast-conserving therapy for women with breast cancer consists of local excision of the tumour (achieving clear margins) followed by radiotherapy (RT). Most true recurrences occur in the same quadrant as the original tumour. Whole breast radiotherapy (WBRT) may not protect against the development of a new primary cancer developing in other quadrants of the breast. In this Cochrane Review, we investigated the delivery of radiation to a limited volume of the breast around the tumour bed (partial breast irradiation (PBI)) sometimes with a shortened treatment duration (accelerated partial breast irradiation (APBI)). OBJECTIVES: To determine whether PBI/APBI is equivalent to or better than conventional or hypofractionated WBRT after breast-conserving therapy for early-stage breast cancer. SEARCH METHODS: On 27 August 2020, we searched the Cochrane Breast Cancer Group Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and three trial databases. We searched for grey literature: OpenGrey (September 2020), reference lists of articles, conference proceedings and published abstracts, and applied no language restrictions. SELECTION CRITERIA: Randomised controlled trials (RCTs) without confounding, that evaluated conservative surgery plus PBI/APBI versus conservative surgery plus WBRT. Published and unpublished trials were eligible. DATA COLLECTION AND ANALYSIS: Two review authors (BH and ML) performed data extraction, used Cochrane's risk of bias tool and resolved any disagreements through discussion, and assessed the certainty of the evidence for main outcomes using GRADE. Main outcomes were local recurrence-free survival, cosmesis, overall survival, toxicity (subcutaneous fibrosis), cause-specific survival, distant metastasis-free survival and subsequent mastectomy. We entered data into Review Manager 5 for analysis. MAIN RESULTS: We included nine RCTs that enrolled 15,187 women who had invasive breast cancer or ductal carcinoma in-situ (6.3%) with T1-2N0-1M0 Grade I or II unifocal tumours (less than 2 cm or 3 cm or less) treated with breast-conserving therapy with negative margins. This is the second update of the review and includes two new studies and 4432 more participants. Local recurrence-free survival is probably slightly reduced (by 3/1000, 95% CI 6 fewer to 0 fewer) with the use of PBI/APBI compared to WBRT (hazard ratio (HR) 1.21, 95% confidence interval (CI) 1.03 to 1.42; 8 studies, 13,168 participants; moderate-certainty evidence). Cosmesis (physician/nurse-reported) is probably worse (by 63/1000, 95% CI 35 more to 92 more) with the use of PBI/APBI (odds ratio (OR) 1.57, 95% CI 1.31 to 1.87; 6 studies, 3652 participants; moderate-certainty evidence). Overall survival is similar (0/1000 fewer, 95% CI 6 fewer to 6 more) with PBI/APBI and WBRT (HR 0.99, 95% CI 0.88 to 1.12; 8 studies, 13,175 participants; high-certainty evidence). Late radiation toxicity (subcutaneous fibrosis) is probably increased (by 14/1000 more, 95% CI 102 more to 188 more) with PBI/APBI (OR 5.07, 95% CI 3.81 to 6.74; 2 studies, 3011 participants; moderate-certainty evidence). The use of PBI/APBI probably makes little difference (1/1000 less, 95% CI 6 fewer to 3 more) to cause-specific survival (HR 1.06, 95% CI 0.83 to 1.36; 7 studies, 9865 participants; moderate-certainty evidence). We found the use of PBI/APBI compared with WBRT probably makes little or no difference (1/1000 fewer (95% CI 4 fewer to 6 more)) to distant metastasis-free survival (HR 0.95, 95% CI 0.80 to 1.13; 7 studies, 11,033 participants; moderate-certainty evidence). We found the use of PBI/APBI in comparison with WBRT makes little or no difference (2/1000 fewer, 95% CI 20 fewer to 20 more) to mastectomy rates (OR 0.98, 95% CI 0.78 to 1.23; 3 studies, 3740 participants, high-certainty evidence). AUTHORS' CONCLUSIONS: It appeared that local recurrence-free survival is probably worse with PBI/APBI; however, the difference was small and nearly all women remain free of local recurrence. Overall survival is similar with PBI/APBI and WBRT, and we found little to no difference in other oncological outcomes. Some late effects (subcutaneous fibrosis) may be worse with PBI/APBI and its use is probably associated with worse cosmetic outcomes. The limitations of the data currently available mean that we cannot make definitive conclusions about the efficacy and safety or ways to deliver PBI/APBI. We await completion of ongoing trials.

A prospective evaluation of treatment recommendations compared to outcomes for a lung cancer multidisciplinary team and legal implications.

INTRODUCTION: This cross-sectional study compared treatment recommendations made by a respiratory multi-disciplinary team with the treatment received by those patients in practice. The aim was to evaluate the rate at which patients were treated in keeping with MDT recommendations. It was hypothesised that most patients would be treated in accordance with these recommendations. These data were then used to provide a practical basis to consider the potential legal liability of multi-disciplinary teams. METHODS: All patients discussed in the Princess Alexandra Hospital Lung MDT over a three-month period were included. The recommendations made by the MDT were compared with the treatment received. Where available, the reason for any change in management plan was recorded. RESULTS: 74/109 evaluable patients were treated in accordance with the MDT recommendation. A further 7 patients had commenced treatment prior to MDT discussion. The most common reasons for change in management were patient choice (n = 6) or deterioration in clinical condition prior to treatment (n = 6). CONCLUSION: As hypothesised, there was a high rate of treatment in accordance with recommendations made by the MDT. Changes in management are mostly related to patient preference or change in condition after MDT discussion. In practice, there are only limited opportunities for an MDT to be liable for patient outcomes. It is suggested however that careful documentation and representation of cases where appropriate could further mitigate this risk.

A Randomized Phase 3 Trial of Palliative Radiation Therapy Versus Concurrent Chemotherapy and Palliative Radiation Therapy in Patients With Good Performance Status, Locally Advanced, or Metastatic Non-Small Cell Lung Cancer With Symptoms due to Intrathoracic Disease Who are Not Suitable for Radical Chemo-radiation Therapy: Results of the Trans-Tasman Radiation Oncology Group 11.03 Trial.

PURPOSE: We compared intrathoracic symptom response rate, quality of life (QOL) and toxicity in patients with non-small cell lung cancer (NSCLC) not suitable for radical chemo-radiation therapy, experiencing symptoms from intrathoracic disease, who were randomized to receive palliative radiation therapy (PRT36/12) or concurrent chemotherapy and PRT (C-PRT40/20). METHODS AND MATERIALS: We included patients with stage III or IV NSCLC, with a Eastern Cooperative Oncology Group Performance status 0 to 1, who were experiencing at least one of the following: dyspnea, cough, hemoptysis, or chest pain. The primary outcome was a change in intrathoracic response rate from baseline to 6 weeks post completion of therapy using (1) a composite measure, the Intrathoracic Symptom Burden Index(ISBI), and (2) individual symptom scores measured by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) and Quality of Life Questionnaire - Lung Cancer 13 item (QLQ-LC 13) instruments. RESULTS: Seventy-six patients were recruited with 68 eligible for analysis. In addition, 42.6% and 57.4% had stage III and IV disease, respectively. The Intrathoracic Symptom Burden Index was significantly lower at 6 weeks posttreatment than at baseline (adjusted mean difference -8.77, standard error 2.67; 95% confidence interval, -13.97% to -3.58%; P < .01) for the entire cohort with no difference between trial arms (P = .34). Both treatments provided effective palliation of individual symptoms with no significant difference between trial arms. QOL during treatment was significantly better for patients receiving C-PRT(40/20). There was no difference between arms in overall QOL between baseline and 6 weeks posttreatment. There was no difference in toxicity between treatment arms during treatment nor between baseline and 6 weeks posttreatment. There was no difference in progression-free survival. A nonstatistically significant 3-month improvement in median survival favored C-PRT(40/20). CONCLUSION: PRT(36/12) and C-PRT(40/20) provide effective symptom palliation in patients with stage III NSCLC not suitable for radical chemo-radiation therapy and in patients with stage IV disease. Chemotherapy added to PRT(40/20) does not provide superior symptomatic relief in this patient cohort.

Incidence of hippocampal metastases in non-small-cell lung cancer.

OBJECTIVES: Patients with locally advanced non-small-cell lung cancer (LA-NSCLC) develop brain metastases in 25-50% of cases during the course of their disease. Data on the incidence of metastases occurring in the hippocampus/perihippocampal zones are limited. This is important when considering hippocampal-sparing brain radiation (HS-BR), a method that could potentially reduce the neurocognitive impact of such treatment. The aim of this study was to assess the incidence of hippocampal/perihippocampal metastases in a cohort of patients with advanced NSCLC treated at our institution. METHODS: This retrospective cohort study included NSCLC patients discussed at our institutional lung cancer multidisciplinary meeting between 2000 and 2016. MRI and contrast-enhanced CT (ceCT) brain images were reviewed to assess the incidence of hippocampal/perihippocampal metastases including metastases within the hippocampal subgranular zone and a 5 mm margin (hippocampal avoidance region) defined as per the RTOG 0933 study. RESULTS: Of 2146 patients reviewed, 357 (16.6%) had brain metastases. A total of 335 patients had available MRI/ceCT brain images for review. Thirty (9%) patients had brain metastases in the hippocampal avoidance region, 8 (2.4%) with hippocampal metastases and 22 (6.6%) with perihippocampal metastases. Univariate analyses did not show an association between developing metastases in the hippocampal avoidance region and age (P = 0.75), gender (P = 0.91) and tumour type (P = 0.298). CONCLUSION: The incidence of metastases in the hippocampal avoidance region in our large cohort of patients was 9%. With low rates of metastases in this region, HS-BR can be considered a feasible option in the management of patients with advanced NSCLC.

Identifying breast cancer patients who gain the most dosimetric benefit from deep inspiration breath hold radiotherapy.

INTRODUCTION: Deep inspiration breath hold (DIBH) has been proven to reduce cardiac dose for women receiving left breast and chest wall radiation therapy. However, it utilises extra departmental resources and patient exertion. The aim of this exploratory study was to investigate if any factors existed that could identify breast cancer patients who may benefit most from DIBH, to facilitate appropriate utilisation of departmental resources. METHODS: Left-sided breast cancer patients aged 18-70 years, and right-sided breast cancer patients with internal mammary nodes included, were recruited. DIBH and free breathing (FB) plans were created for all patients. Patient demographic and clinical history were recorded. Variables including lung threshold value, lung volume, patient separation, maximum heart in field, volume of planning target volume (PTV), heart dose, ipsilateral lung dose were compared between plans. RESULTS: Plans for 31 patients were analysed. No correlations were found between lung threshold value or patient separation and cardiac dose. Moderate to strong correlations were found with BMI, PTV volume and lung volume change however no definitive thresholds were determined. A significant difference was found in the maximum heart in field between DIBH and FB (P < 0.001) with those patients with greater than 0.7 cm heart in the field on the FB scan demonstrating greater reductions in mean heart dose. CONCLUSION: Maximum heart in the field of greater than 0.7 cm in FB could be a potential factor to identify patients who may benefit most from DIBH. This factor warrants investigation in a larger patient cohort to test its validity.

Radiation therapy for augmenting the efficacy of immunotherapy in advanced non-small cell lung cancer: a case-controlled study.

This study investigated the effects of previous radiation therapy on outcomes from nivolumab in advanced NSCLC, and found that previous radiation therapy resulted in significantly higher survival in patients treated with nivolumab for advanced NSCLC http://bit.ly/3btOFSL.

Prior or concurrent radiotherapy and nivolumab immunotherapy in non-small cell lung cancer.

BACKGROUND: Studies suggest that combining radiotherapy (RT) with programmed cell death protein 1 (PD-1) blockade may elicit a synergistic antitumor response. We aimed to assess whether prior or concurrent RT was associated with improved disease control in patients with metastatic non-small cell lung cancer (NSCLC) treated with nivolumab. METHODS: We conducted a retrospective study of patients receiving nivolumab as second or subsequent line therapy for metastatic NSCLC. Patients were categorized into those who received any RT for NSCLC prior to or during nivolumab therapy, and those with no history of RT for NSCLC. RESULTS: A total of 85 patients received nivolumab between July 2015 and December 2016 and were followed up for a median of 15 months. Sixty-five patients (76.4%) received RT prior to or during nivolumab and 20 patients (23.6%) received nivolumab alone. Baseline characteristics of age, performance status, histology, smoking status and previous therapy were similar between the two groups. Prior or concurrent RT was associated with a superior PFS, median 2.8 months with RT versus 1.3 months without RT (Hazard Ratio (HR) = 0.494; 95% Confidence Interval (CI), 0.279-0.873; P = 0.02). The median OS of the group receiving RT was 6.4 months versus 4.2 months for the no RT group (P = 0.20). RT was not associated with an increase in toxicity. CONCLUSION: RT prior to or concurrent with nivolumab for metastatic NSCLC was associated with a modest improvement in PFS over nivolumab alone with no evidence of increase in adverse effects. RT may potentiate the effect of anti-PD-1 immunotherapy in NSCLC.

Contouring experiences amongst Australian, New Zealand and Singaporean radiation oncology trainees. Is it enough? What next?

INTRODUCTION: This paper reports the key findings of the first survey of Australian, New Zealand (ANZ) and Singaporean radiation oncology trainees on contouring and planning. METHODS: The survey was conducted from May to July 2018 using a 35-question instrument. It was emailed to all ANZ and Singaporean trainees on the Royal Australian and New Zealand College of Radiologists (RANZCR) database with at least 6 months experience. The questions related to demographics, time spent on contouring, most difficult sites to contour, most useful atlas, feedback on contouring, interaction with radiation therapists, plan reviews, stereotactic radiation therapy (SBRT), brachytherapy and suggested areas of improvement. Respondents were assured that their responses were anonymous. RESULTS: The response rate was 50% (54/108). Most respondents were from New South Wales (31%) with nearly all working full time (96%) and a large majority in public practice (89%). All respondents had at least one other accredited trainee at their site. The large majority (75%) spent at least two hours per week contouring, but nearly 80% had to spend some time out of hours contouring with 10% performing all their contouring out of hours. Two-thirds of respondents indicated there was insufficient time for contouring with over half having no allocated time for this activity. All respondents were allowed to independently contour by their consultants and were allowed to do radical and palliative cases. The most difficult cases to contour were head and neck and the upper gastrointestinal sites with the RTOG atlas the most useful guide. All trainee respondents received feedback on their contouring which was most often face to face. Interaction with radiation therapists was valuable and more interaction was desired. Two-thirds (67%) of respondents had the opportunity to review treatment plans with consultants with one to two cases per week being the most common numbers reviewed, but this was usually not done (87%) on an allocated time in the roster. The large majority (90%) had the opportunity to be involved in brachytherapy, but this dropped to 60% for SBRT. Three quarters (73%) of respondents felt that there was not enough time spent on contouring, planning and evaluation of plans. CONCLUSIONS: This initial detailed survey of ANZ and Singaporean trainees on contouring and planning indicates that dedicated protected time without interruption is required for this integral activity with current hours spent on this activity inadequate. Optimisation and improvement in a number of areas is required. Feedback from this study should be adopted by sites and networks. Feedback could also be considered as the Faculty of Radiation Oncology transitions into programmatic assessment.

Deep inspiration breath hold in breast cancer: Development and analysis of a patient experience questionnaire.

INTRODUCTION: Evidence that Deep Inspiration Breath Hold (DIBH) can reduce cardiac dose during left-sided breast radiation therapy (RT) has led to widespread uptake of this technology. There is a paucity of published information documenting the impact of this technique on the patient's treatment experience. The aim of this study was to develop a tool to assess the patient's experience with the introduction of DIBH using the Elekta® Active Breathing Coordinator (ABC) in a single institution. METHODS: A patient experience questionnaire was developed and was completed at three different stages of the patient's treatment; at planning, during the second week of treatment (day 6-10) and during the final week of treatment. RESULTS: Questionnaire data were collected from 30 patients, who underwent DIBH breast treatment during the period March 2016 to May 2017. Patients were very happy with their use of the ABC equipment and most felt they were well supported and informed during their treatment. Levels of general fatigue and personal anxiety were identified to significantly increase from planning to the conclusion of treatment (P = 0.002 and P < 0.001 respectively). CONCLUSIONS: This study produced a useful tool to measure patient experience during DIBH treatment. It demonstrated that the use of the technique was acceptable to patients and did not increase their distress. It provided a compelling case for the provision of tailored, well-communicated information, consistent routine and emotional support for patients throughout their entire treatment. The tool could be employed to assess the patient experience as new technologies are introduced into RT.

Improving plan quality for prostate volumetric-modulated arc therapy.

We critically evaluated the quality and consistency of volumetric-modulated arc therapy (VMAT) prostate planning at a single institution to quantify objective measures for plan quality and establish clear guidelines for plan evaluation and quality assurance. A retrospective analysis was conducted on 34 plans generated on the Pinnacle3 version 9.4 and 9.8 treatment planning system to deliver 78 Gy in 39 fractions to the prostate only using VMAT. Data were collected on contoured structure volumes, overlaps and expansions, planning target volume (PTV) and organs at risk volumes and relationship, dose volume histogram, plan conformity, plan homogeneity, low-dose wash, and beam parameters. Standard descriptive statistics were used to describe the data. Despite a standardized planning protocol, we found variability was present in all steps of the planning process. Deviations from protocol contours by radiation oncologists and radiation therapists occurred in 12% and 50% of cases, respectively, and the number of optimization parameters ranged from 12 to 27 (median 17). This contributed to conflicts within the optimization process reflected by the mean composite objective value of 0.07 (range 0.01 to 0.44). Methods used to control low-intermediate dose wash were inconsistent. At the PTV rectum interface, the dose-gradient distance from the 74.1 Gy to 40 Gy isodose ranged from 0.6 cm to 2.0 cm (median 1.0 cm). Increasing collimator angle was associated with a decrease in monitor units and a single full 6 MV arc was sufficient for the majority of plans. A significant relationship was found between clinical target volume-rectum distance and rectal tolerances achieved. A linear relationship was determined between the PTV volume and volume of 40 Gy isodose. Objective values and composite objective values were useful in determining plan quality. Anatomic geometry and overlap of structures has a measurable impact on the plan quality achieved for prostate patients being treated with VMAT. By evaluating multiple planning variables, we have been able to determine important factors influencing plan quality and develop predictive models for quality metrics that have been incorporated into our new protocol and will be tested and refined in future studies.

Radiation oncology directors of training survey 2016: Perspectives and challenges.

INTRODUCTION: This paper reports the key findings of the first survey of Australian and New Zealand Radiation Oncology Directors of Training (DoTs) dealing with their perspectives, experiences and challenges. METHODS: The survey was conducted in September 2016 using a 34-question instrument. It was emailed to all radiation oncology DoTs listed on the Royal Australian and New Zealand College of Radiologists (RANZCR) database. The questions related to demographics, protected time, weekly activities, support, the value of curriculum assessments, challenges and suggested improvements. Respondents were assured that their responses were anonymous. RESULTS: The response rate was 59.6% (31/52). The median age of respondents was in the 41 to 45 age bracket, but nearly one quarter were over 45 years of age. The median time respondents had been in the role was three to five years (range <0.5 to >10) with the median number of trainees supervised being four (range 1-8). Thirty-five percent had a co DoT. DoTs spent a median of three hours per week on the role (range <1 to >8) with most respondents (67.7%) requiring time during and out of work performing the role, but ten percent claimed it was done out of hours only. Nearly all DoTs were aware they should have protected time, but only just half received it. The educational aspects of training dominated weekly activities, but rostering, specific trainee issues and administration were also featured. Time issues were the greatest challenge for respondents with clinical assignments the most challenging assessment. However, more emphasis on contouring and planning was thought to be required. All DoTs found the dedicated DoT workshops useful, but felt future discussions on trainees in difficulty could be emphasized. The vast majority felt supported by their training site and the College. All respondents believed in the role with most having an interest in educational activities. The majority of respondents (85%) intended to continue in the role for the next 1 to 2 years, but this dropped to 45% when asked about continuing for 5 years. CONCLUSIONS: This survey of predominantly experienced DoTs, indicated that the role was deemed to be of value in delivering optimal training. The most significant challenges faced by DoTs were finding sufficient time to deal with the responsibilities of the role and dealing with underperforming trainees. Feedback on the currently employed work based assessments will be considered as FRO transitions into programmatic assessment. Furthermore, a desire for training in how to deal with trainees in difficulty, underperforming or unsuitable trainees is noted. Future work is planned following refinements of the survey instrument; and, will also explore stress and burnout in the DoT cohort.

Patterns of care for ductal carcinoma in situ of the breast: Queensland's experience over a decade.

OBJECTIVES: To review management of ductal carcinoma in situ (DCIS) of the breast in Queensland, with reference to breast conserving surgery (BCS) and adjuvant radiation therapy (RT). In addition, we examined the incidence of invasive breast cancer recurrence and factors predictive of invasive recurrence. MATERIALS AND METHODS: A retrospective review of the Queensland Oncology Repository identified women with resected DCIS (TisN0) ± adjuvant RT between 2003 and 2012. Time to invasive breast cancer recurrence was analysed using the Kaplan Meier method. Median follow-up was 4.9 years. RESULTS: 3038 women had surgery. 940 (31%) had mastectomy and 2098 (69%) underwent BCS. Of 2098 women having BCS, 1100 (52%) received BCS alone and 998(48%) received adjuvant RT. The use of RT significantly increased over the decade from 25% to 62% (p=<0.001). Clinicopathological factors associated with RT use on multivariate analysis included age ≤70, higher socioeconomic status, larger tumour size, higher nuclear grade and surgical margins ≤5 mm. Invasive breast cancer recurrence at 5 years was 1.7% [95% CI 1.0-3.0] in RT group versus 2.8% [95% CI 2.1-3.8] in BCS alone group. Factors associated with increased risk of invasive recurrence on multivariate analysis were age <40 and surgical margins ≤2 mm. CONCLUSION: The use of adjuvant RT in Queensland significantly increased between 2003 and 2012. Selection of patients for RT was based on clinicopathological factors associated with higher recurrence risk. Although longer follow-up is required, the selective use of radiation therapy after BCS is associated with a low rate of invasive breast cancer recurrence at 5 years.

Vector-model-supported optimization in volumetric-modulated arc stereotactic radiotherapy planning for brain metastasis.

Long planning time in volumetric-modulated arc stereotactic radiotherapy (VMA-SRT) cases can limit its clinical efficiency and use. A vector model could retrieve previously successful radiotherapy cases that share various common anatomic features with the current case. The prsent study aimed to develop a vector model that could reduce planning time by applying the optimization parameters from those retrieved reference cases. Thirty-six VMA-SRT cases of brain metastasis (gender, male [n = 23], female [n = 13]; age range, 32 to 81 years old) were collected and used as a reference database. Another 10 VMA-SRT cases were planned with both conventional optimization and vector-model-supported optimization, following the oncologists' clinical dose prescriptions. Planning time and plan quality measures were compared using the 2-sided paired Wilcoxon signed rank test with a significance level of 0.05, with positive false discovery rate (pFDR) of less than 0.05. With vector-model-supported optimization, there was a significant reduction in the median planning time, a 40% reduction from 3.7 to 2.2 hours (p = 0.002, pFDR = 0.032), and for the number of iterations, a 30% reduction from 8.5 to 6.0 (p = 0.006, pFDR = 0.047). The quality of plans from both approaches was comparable. From these preliminary results, vector-model-supported optimization can expedite the optimization of VMA-SRT for brain metastasis while maintaining plan quality.

Vector-model-supported approach in prostate plan optimization.

Lengthy time consumed in traditional manual plan optimization can limit the use of step-and-shoot intensity-modulated radiotherapy/volumetric-modulated radiotherapy (S&S IMRT/VMAT). A vector model base, retrieving similar radiotherapy cases, was developed with respect to the structural and physiologic features extracted from the Digital Imaging and Communications in Medicine (DICOM) files. Planning parameters were retrieved from the selected similar reference case and applied to the test case to bypass the gradual adjustment of planning parameters. Therefore, the planning time spent on the traditional trial-and-error manual optimization approach in the beginning of optimization could be reduced. Each S&S IMRT/VMAT prostate reference database comprised 100 previously treated cases. Prostate cases were replanned with both traditional optimization and vector-model-supported optimization based on the oncologists' clinical dose prescriptions. A total of 360 plans, which consisted of 30 cases of S&S IMRT, 30 cases of 1-arc VMAT, and 30 cases of 2-arc VMAT plans including first optimization and final optimization with/without vector-model-supported optimization, were compared using the 2-sided t-test and paired Wilcoxon signed rank test, with a significance level of 0.05 and a false discovery rate of less than 0.05. For S&S IMRT, 1-arc VMAT, and 2-arc VMAT prostate plans, there was a significant reduction in the planning time and iteration with vector-model-supported optimization by almost 50%. When the first optimization plans were compared, 2-arc VMAT prostate plans had better plan quality than 1-arc VMAT plans. The volume receiving 35 Gy in the femoral head for 2-arc VMAT plans was reduced with the vector-model-supported optimization compared with the traditional manual optimization approach. Otherwise, the quality of plans from both approaches was comparable. Vector-model-supported optimization was shown to offer much shortened planning time and iteration number without compromising the plan quality.