Head-and-Neck Target Delineation Among Radiation Oncology Residents After a Teaching Intervention: A Prospective, Blinded Pilot Study

Quality of Radiotherapy Workforce Training within the USA

The training, competency requirements and scope of practice of professionals within a radiation oncology department vary across countries. The purpose of this review is to shed light on the current status of radiotherapy training in the USA by discussing current benchmarks for medical residency, physics residency, radiation therapy and dosimetry training programmes. Although there are notable strengths, the US radiotherapy workforce training system also faces several challenges when it comes to standardising education to develop a competent workforce that meets societal needs. Continued efforts are needed at a systemic level to improve training in areas such as brachytherapy and proton therapy, promote research involvement and develop trainees who are equipped to form a competent radiation therapy workforce.

Development of Prostate Bed Delineation Consensus Guidelines for Magnetic Resonance Image-Guided Radiotherapy and Assessment of Its Effect on Interobserver Variability

PURPOSE

The use of magnetic resonance imaging (MRI) in radiotherapy planning is becoming more widespread, particularly with the emergence of MRI-guided radiotherapy systems. Existing guidelines for defining the prostate bed clinical target volume (CTV) show considerable heterogeneity. This study aimed to establish baseline interobserver variability (IOV) for prostate bed CTV contouring on MRI, develop international consensus guidelines, and evaluate its effect on IOV.

METHODS AND MATERIALS

Participants delineated the CTV on 3 MRI scans, obtained from the Elekta Unity MR-Linac, as per their normal practice. Radiation oncologist contours were visually examined for discrepancies, and interobserver comparisons were evaluated against simultaneous truth and performance level estimation (STAPLE) contours using overlap metrics (Dice similarity coefficient and Cohen's kappa), distance metrics (mean distance to agreement and Hausdorff distance), and volume measurements. A literature review of postradical prostatectomy local recurrence patterns was performed and presented alongside IOV results to the participants. Consensus guidelines were collectively constructed, and IOV assessment was repeated using these guidelines.

RESULTS

Sixteen radiation oncologists' contours were included in the final analysis. Visual evaluation demonstrated significant differences in the superior, inferior, and anterior borders. Baseline IOV assessment indicated moderate agreement for the overlap metrics while volume and distance metrics demonstrated greater variability. Consensus for optimal prostate bed CTV boundaries was established during a virtual meeting. After guideline development, a decrease in IOV was observed. The maximum volume ratio decreased from 4.7 to 3.1 and volume coefficient of variation reduced from 40% to 34%. The mean Dice similarity coefficient rose from 0.72 to 0.75 and the mean distance to agreement decreased from 3.63 to 2.95 mm.

CONCLUSIONS

Interobserver variability in prostate bed contouring exists among international genitourinary experts, although this is lower than previously reported. Consensus guidelines for MRI-based prostate bed contouring have been developed, and this has resulted in an improvement in contouring concordance. However, IOV persists and strategies such as an education program, development of a contouring atlas, and further refinement of the guidelines may lead to additional improvements.

Outcomes among oropharyngeal and oral cavity cancer patients treated with postoperative volumetric modulated arctherapy

Background

Presently, there are few published reports on postoperative radiation therapy for oropharyngeal and oral cavity cancers treated with IMRT/VMAT technique. This study aimed to assess the oncological outcomes of this population treated with postoperative VMAT in our institution, with a focus on loco-regional patterns of failure.

Material and methods

Between 2011 and 2019, 167 patients were included (40% of oropharyngeal cancers, and 60% of oral cavity cancers). The median age was 60 years. There was 64.2% of stage IV cancers. All patients had both T and N surgery. 34% had a R1 margin, 42% had perineural invasion. 72% had a positive neck dissection and 42% extranodal extension (ENE). All patients were treated with VMAT with simultaneous integrated boost with three dose levels: 66Gy in case of R1 margin and/or ENE, 59.4-60Gy on the tumor bed, and 54Gy on the prophylactic areas. Concomittant cisplatin was administrated concomitantly when feasible in case of R1 and/or ENE.

Results

The 1- and 2-year loco-regional control rates were 88.6% and 85.6% respectively. Higher tumor stage (T3/T4), the presence of PNI, and time from surgery >45 days were significant predictive factors of worse loco-regional control in multivariate analysis (p=0.02, p=0.04, and p=0.02). There were 17 local recurrences: 11 (64%) were considered as infield, 4 (24%) as marginal, and 2 (12%) as outfield. There were 9 regional recurrences only, 8 (89%) were considered as infield, and 1 (11%) as outfield. The 1- and 2-year disease-free survival (DFS) rates were 78.9% and 71.8% respectively. The 1- and 2-year overall survival (OS) rates were 88.6% and 80% respectively. Higher tumor stage (T3/T4) and the presence of ENE were the two prognostic factors significantly associated with worse DFS and OS in multivariate analysis.

Conclusion

Our outcomes for postoperative VMAT for oral cavity and oropharyngeal cancers are encouraging, with high rates of loco-regional control. However, the management of ENE still seems challenging.

Nasopharyngeal cancer: the impact of guidelines and teaching on radiation target volume delineation

Target volume delineation in the radiation treatment of nasopharyngeal cancer is challenging due to several reasons such as the complex anatomy of the site, the need for the elective coverage of definite anatomical regions, the curative intent of treatment and the rarity of the disease, especially in non-endemic areas. We aimed to analyze the impact of educational interactive teaching courses on target volume delineation accuracy between Italian radiation oncology centers. Only one contour dataset per center was admitted. The educational course consisted in three parts: (1) The completely anonymized image dataset of a T4N1 nasopharyngeal cancer patient was shared between centers before the course with the request of target volume and organs at risk delineation; (2) the course was held online with dedicated multidisciplinary sessions on nasopharyngeal anatomy, nasopharyngeal cancer pattern of diffusion and on the description and explanation of international contouring guidelines. At the end of the course, the participating centers were asked to resubmit the contours with appropriate corrections; (3) the pre- and post-course contours were analyzed and quantitatively and qualitatively compared with the benchmark contours delineated by the panel of experts. The analysis of the 19 pre- and post-contours submitted by the participating centers revealed a significant improvement in the Dice similarity index in all the clinical target volumes (CTV1, CTV2 and CTV3) passing from 0.67, 0.51 and 0.48 to 0.69, 0.65 and 0.52, respectively. The organs at risk delineation was also improved. The qualitative analysis consisted in the evaluation of the inclusion of the proper anatomical regions in the target volumes; it was conducted following internationally validated guidelines of contouring for nasopharyngeal radiation treatment. All the sites were properly included in target volume delineation by  >50% of the centers after correction. A significant improvement was registered for the skull base, the sphenoid sinus and the nodal levels. These results demonstrated the important role that educational courses with interactive sessions could have in such a challenging task as target volume delineation in modern radiation oncology.

Improving radiation physics, tumor visualisation, and treatment quantification in radiotherapy with spectral or dual-energy CT

Over the past decade, spectral or dual‐energy CT has gained relevancy, especially in oncological radiology. Nonetheless, its use in the radiotherapy (RT) clinic remains limited. This review article aims to give an overview of the current state of spectral CT and to explore opportunities for applications in RT.

In this article, three groups of benefits of spectral CT over conventional CT in RT are recognized. Firstly, spectral CT provides more information of physical properties of the body, which can improve dose calculation. Furthermore, it improves the visibility of tumors, for a wide variety of malignancies as well as organs‐at‐risk OARs, which could reduce treatment uncertainty. And finally, spectral CT provides quantitative physiological information, which can be used to personalize and quantify treatment.

Remote Contouring and Virtual Review during the COVID-19 Pandemic (RECOVR-COVID19): Results of a Quality Improvement Initiative for Virtual Resident Training in Radiation Oncology

The need to minimize in-person interactions during the COVID-19 pandemic has led to fewer clinical learning opportunities for trainees. With ongoing utilization of virtual platforms for resident education, efforts to maximize their value are essential. Herein we describe a resident-led quality improvement initiative to optimize remote contouring and virtual contour review. From April to June 2020, radiation oncology (RO) residents at our institution were assigned modified duties. We implemented a program to source and assign cases to residents for remote contouring and to promote and optimize virtual contour review. Resident-perceived educational value was prospectively collected and analyzed. All nine RO residents at our institution (PGY1–5) participated, and 97 cases were contoured during the evaluation period. Introduction of the Remote Contouring and Virtual Review (RECOVR) program coincided with a significant increase in mean cases contoured per week, from 5.5 to 17.3 (p = 0.015), and an increased proportion of cases receiving virtual review, from 14.8% to 58.6% (p < 0.001). Residents reported that the value of immediate feedback during virtual review was similar to that of in-person review (4.6 ± 0.1 vs. 4.5 ± 0.2, p = 0.803) and significantly higher than feedback received post hoc (e.g., email; 3.6 ± 0.2, p < 0.001). The implementation of a remote process for contour review led to significant increases in contouring, and virtual contour review was rated as highly as in-person interactions. Our findings provide a data-driven rationale and framework for integrating remote contouring and virtual review into competency-based medical education.

A rapid review of influential factors and appraised solutions on organ delineation uncertainties reduction in radiotherapy

Background and purpose.Accurate volume delineation plays an essential role in radiotherapy. Contouring is a potential source of uncertainties in radiotherapy treatment planning that could affect treatment outcomes. Therefore, reducing the degree of contouring uncertainties is crucial. The role of utilized imaging modality in the organ delineation uncertainties has been investigated. This systematic review explores the influential factors on inter-and intra-observer uncertainties of target volume and organs at risk (OARs) delineation focusing on the used imaging modality for these uncertainties reduction and the reported subsequent histopathology and follow-up assessment.Methods and materials.An inclusive search strategy has been conducted to query the available online databases (Scopus, Google Scholar, PubMed, and Medline). 'Organ at risk', 'target', 'delineation', 'uncertainties', 'radiotherapy' and their relevant terms were utilized using every database searching syntax. Final article extraction was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Included studies were limited to the ones published in English between 1995 and 2020 and that just deal with computed tomography (CT) and magnetic resonance imaging (MRI) modalities.Results.A total of 923 studies were screened and 78 were included of which 31 related to the prostate 20 to the breast, 18 to the head and neck, and 9 to the brain tumor site. 98% of the extracted studies performed volumetric analysis. Only 24% of the publications reported the dose deviations resulted from variation in volume delineation Also, heterogeneity in studied populations and reported geometric and volumetric parameters were identified such that quantitative synthesis was not appropriate.Conclusion.This review highlightes the inter- and intra-observer variations that could lead to contouring uncertainties and impede tumor control in radiotherapy. For improving volume delineation and reducing inter-observer variability, the implementation of well structured training programs, homogeneity in following consensus and guidelines, reliable ground truth selection, and proper imaging modality utilization could be clinically beneficial.

Accuracy of automatic structure propagation for daily magnetic resonance image-guided head and neck radiotherapy

BACKGROUND AND PURPOSE

Deformable image registration (DIR) and contour propagation are used in daily online adaptation for hybrid MRI linac (MRL) treatments. The accuracy of the propagated contours may vary depending on the chosen workflow (WF), affecting the amount of required manual corrections. This study investigated the impact of three different WFs of contour propagations produced by a clinical treatment planning system for a high-field MRL on head and neck cancer patients.

METHODS

Seventeen patients referred for curative radiotherapy for oropharyngeal cancer underwent standard CT-based dose planning and MR scans in the treatment position for planning (pMR), and at the 10th (MR10), 20th (MR20) and 30th (MR30) fraction (±2). The primary tumour, a metastatic lymph node and 8 organs at risk were manually delineated on each set of T2 weighted images. Delineations were repeated one month later on the pMR by the same observer to determine the intra-observer variation (IOV). Three WFs were used to deform images in the treatment planning system for the high-field MRL: In WF1, only the planning image and contours were used as a reference for DIR and propagation to MR_10,20,30. The most recently acquired image set prior to the daily images was deformed and uncorrected (WF2) versus manually corrected (WF3) structures propagated to the session image. Dice similarity coefficient (DSC), mean surface distance (MSD) and Hausdorff distance (HD) were calculated for each structure in each model.

RESULTS

Population median DSC, MSD and HD for WF1 and WF3 were similar and slightly better than for WF2. WF3 provided higher accuracy than WF1 for structures that are likely to shrink. All DIR workflows were less accurate than the IOV.

CONCLUSIONS

WF1 and WF3 provide higher accuracy in structure propagation than WF2. Manual revision and correction of propagated structures are required for all evaluated workflows.

Influence of inter-observer delineation variability on radiomic features of the parotid gland

PURPOSE

This study aimed to quantify the variability in the values of radiomic features extracted from a right parotid gland (RPG) delineated by a series of independent observers.

METHODS

This was a secondary analysis of anonymous data from a delineation workshop. Inter-observer variability of the RPG from 40 participants was quantified using DICE similarity coefficient (DSC) and Hausdorff distance (HD). An additional contour was generated using Varian SmartSegmentation. Radiomic features extracted include four shape features, six histogram features, and 32 texture features. The absolute mean paired percentage difference (PPD) in feature values from the expert and participants were ranked . Feature robustness was classified using pre- determined thresholds.

RESULTS

63% of participants achieved a DSC > 0.7, the auto- segmentation DSC was 0.76. The average HD for the participants was 16.16 mm ± 0.66 mm, and 15.16 mm for the auto-segmentation. 48% (n = 20) and 33% (n = 14) of features were deemed to be robust with a mean absolute PPD < 5%, for the auto-segmentation and manual delineations respectively; the majority of which were from the grey-run length matrix family. 7% (n = 3) of features from the auto- segmentation and 10% (n = 4) from the manual contours were deemed to be unstable with a mean absolute PPD > 50%. The value of the most robust feature was not related to DSC and HD.

CONCLUSION

Inter-observer delineation variability affects the value of the radiomic features extracted from the RPG. This study identifies the radiomic features least sensitive to these uncertainties. Further investigation of the clinical relevance of these features in prediction of xerostomia is warranted.

Learning radiotherapy: the state of the art

BACKGROUND

The last two decades have seen revolutionary developments in both radiotherapy technology and postgraduate medical training. Trainees are expected to attain competencies using a mix of experiential learning, formal postgraduate teaching, self-directed learning and peer education. Radiation (Clinical) Oncology is a recognised 'craft specialty' where the apprenticeship model of training is applicable. This scoping review examines the evidence in relation to how medical trainees learn radiotherapy.

METHODS

A systematic search of MEDINE and EMBASE was undertaken to identify studies of trainee and/or trainer experience of radiotherapy learning published 1999-2018. Results pertaining to Medical Oncology, workforce trends, undergraduate radiotherapy exposure, academic training, global health, non-medical staff, health service infrastructure and recruitment to training programmes were not included.

RESULTS

A total of 146 publications were included in the synthesis. Five themes were apparent through careful iterative analysis representing broadly inter-related issues. Most articles studied radiotherapy training from the perspective of the trainee doctor. Most literature reports results of observational, local or national surveys with a tightly defined scope. Considerable variation exists within hospitals, within countries, over time and between different curricular areas.

CONCLUSIONS

Medical education has not kept pace with changes in the field of radiotherapy and large differences are demonstrated in experience between trainees in different hospitals, countries and training stages. Interpersonal relationships, departmental organisation, and national curricula impact on training quality. Qualitative and quantitative research examining modern radiotherapy learning has been uncommon and uncoordinated, until recently. To date no single study has been designed to comprehensively assess a department's training scheme.

Systematic review of educational interventions to improve contouring in radiotherapy

BACKGROUND AND PURPOSE

Contouring is a critical step in the radiotherapy process, but there is limited research on how to teach it and no consensus about the best method. We summarize the current evidence regarding improvement of contouring skills.

METHODS AND MATERIALS

Comprehensive literature search of the Pubmed-MEDLINE database, EMBASE database and Cochrane Library to identify relevant studies (independently examined by two investigators) that included baseline contouring followed by a re-contouring assessment after an educational intervention.

RESULTS

598 papers were identified. 16 studies met the inclusion criteria representing 370 participants (average number of participants per study of 23; range (4-141). Regarding the teaching methodology, 5/16 used onsite courses, 8/16 online courses, and 2/16 used blended learning. Study quality was heterogenous. There were only 3 randomized studies and only 3 analyzed the dosimetric impact of improving contouring homogeneity. Dice similarity coefficient was the most common evaluation metric (7/16), and in all these studies at least some contours improved significantly post-intervention. The time frame for evaluating the learning effect of the teaching intervention was almost exclusively short-time, with only one study evaluating the long-term utility of the educational program beyond 6 months.

CONCLUSION

The literature on educational interventions designed to improve contouring performance is limited and heterogenous. Onsite, online and blended learning courses have all been shown to be helpful, however, sample sizes are small and impact assessment is almost exclusively short-term and typically does not take into account the effect on treatment planning. The most effective teaching methodology/format is unknown and impact on daily clinical practice is uncertain.

Prospective International Pilot Study Evaluating the Efficacy of a Self-Guided Contouring Teaching Module With Integrated Feedback for Transitioning From 2D to 3D Treatment Planning

PURPOSE

Transitioning from two-dimensional to three-dimensional treatment planning requires developing contouring skills. Contouring atlases are excellent resources, but they do not provide users active feedback. Developing countries may not have many radiation oncologists experienced in three-dimensional planning to provide training. We sought to develop a standardized self-guided educational module with integrated feedback to teach contouring skills.

METHODS AND MATERIALS

All 18 oncology residents at Black Lion Hospital/Addis Ababa University in Ethiopia were trained to contour the level II lymph node station. Residents took a baseline pretest quiz, survey, and contouring evaluation. Residents then watched an instructional contouring lecture and performed three additional cases with integrated feedback by comparing their contours to gold-standard contours. Residents then took a post-training quiz, survey, and contouring evaluation. Paired t tests and analysis of variance were used for analysis.

RESULTS

Before training, the average number of total cases ever contoured was 2.4 and the average number of head and neck cases contoured was 0.5. Comfort with contouring improved from being "not at all comfortable" to "quite comfortable" after the 3-hour training (P < .001). The standard deviation between the resident contours and gold standard improved from 72.6 cm3 (pretest) to 7.4 cm3 (post-test). The average percentage overlap with the gold-standard contours and Dice similarity coefficient improved with each case performed, from 27.7% and 0.26 (pretest) to 80.1% and 0.77 (post-test), respectively (P < .001). After training, 16 of 18 (88.9%) residents produced a Dice similarity coefficient greater than 0.7, the threshold generally accepted for excellent agreement.

CONCLUSION

This self-guided teaching module was an effective tool for developing level II lymph node contouring skills by providing active feedback and resulted in improved user confidence and accuracy compared with a gold standard. This module can be expanded to other disease sites and countries to further facilitate transitioning to three-dimensional treatment planning in developing countries.

Use of intensity-modulated radiation therapy for nasopharyngeal cancer in Japan: analysis using a national database

Background

Intensity-modulated radiation therapy (IMRT) yields better outcomes and fewer toxicities for radiation therapy (RT) of head and neck cancers (HNCs), including nasopharyngeal cancer (NPC). IMRT is the standard RT treatment and has been widely adopted in Western countries to treat HNCs. However, its uptake in clinical practice among NPC patients has never been studied.

Methods

We investigated the use of IMRT for NPC using data from a nationwide cancer registry to describe the use of IMRT among NPC patients in Japan. We analyzed the data of patients with HNC, including NPC, who underwent IMRT between 2012 and 2014, as recorded in the hospital-based cancer registries linked with insurance claims. We calculated the proportion of patients with NPC who underwent IMRT at each hospital. To evaluate the use of IMRT for NPC, the IMRT use for NPC was compared with the proportion of patients with prostate cancer who underwent IMRT.

Results

Among 508 patients with NPC who underwent RT at one of 87 hospitals, 348 (69%) underwent IMRT. This proportion gradually increased between 2012 and 2014 (62%, 64% and 77%). Meanwhile, 4790 patients with prostate cancer (90%) underwent IMRT. Although some hospitals where IMRT was performed treated many patients with NPC, the proportion of patients with NPC who were treated with IMRT was low.

Conclusions

IMRT has not been widely adopted in Japan for treating NPC. Barriers for adopting its use should be identified to close the gap between the standard and actual medical practice in Japan.

Harmonization of practices between radiotherapy centres in the Nord and Pas-de-Calais regions (France): A three-year evaluation

PURPOSE

The delineation of volumes of interest can be a source of significant interobserver variability. The purpose of this study was to improve the homogeneity of delineation between oncologist-radiotherapists in the territorial departments of Nord and Pas-de-Calais (France) through discussions of clinical cases and the adoption of common published reference documents.

MATERIALS AND METHODS

All eleven radiotherapy centres in the Nord and Pas-de-Calais departments of France participated. The localizations assessed to date included prostate, head and neck, breast and brain cancers. For each localization, the junior or senior physician(s) in charge of pathology delineated the volumes of interest according to their usual practices. Validated indices, including the Dice similarity coefficient, were used to quantify the delineation differences. The anonymized results were presented at two to three annual meetings. A second delineation of the clinical cases was then carried out to quantify homogenization. An evaluation of dosimetry practices was also conducted for prostate cancer. Wilcoxon assay matched data were used.

RESULTS

Our work showed either satisfactory delineation concordance after the initial assessment or improved delineation concordance. For prostate cancer, the Dice similarity coefficient values were greater than 0.6 initially in two of the three clinical cases. For head and neck cancers, a statistically significant improvement was observed for only one of the clinical target volumes. More than half of the Dice similarity coefficient values were greater than 0.6 in the first comparison. The study of clinical cases of breast cancer allowed a homogenization of the delineation of five of the six lymph node clinical target volumes. The dosimetry study of prostate cancer allowed for a homogenization of practices.

CONCLUSION

This work makes it possible to harmonize the delineation practices around validated standards. An extension to the entire Hauts-de-France region is planned.

The impact of a radiologist-led workshop on MRI target volume delineation for radiotherapy

INTRODUCTION

Magnetic resonance imaging (MRI) is increasingly used for target volume delineation in radiotherapy due to its superior soft tissue visualisation compared to computed tomography (CT). The aim of this study was to assess the impact of a radiologist-led workshop on inter-observer variability in volume delineation on MRI.

METHODS

Data from three separate studies evaluating the impact of MRI in lung, breast and cervix were collated. At pre-workshop evaluation, observers involved in each clinical site were instructed to delineate specified volumes. Radiologists specialising in each cancer site conducted an interactive workshop on interpretation of images and anatomy for each clinical site. At post-workshop evaluation, observers repeated delineation a minimum of 2 weeks after the workshops. Inter-observer variability was evaluated using dice similarity coefficient (DSC) and volume similarity (VOLSIM) index comparing reference and observer volumes.

RESULTS

Post-workshop primary gross tumour volumes (GTV) were smaller than pre-workshop volumes for lung with a mean percentage reduction of 10.4%. Breast clinical target volumes (CTV) were similar but seroma volumes were smaller post-workshop on both supine (65% reduction) and prone MRI (73% reduction). Based on DSC scores, improvement in inter-observer variability was seen for the seroma cavity volume on prone MRI with a reduction in DSC score range from 0.4-0.8 to 0.7-0.9. Breast CTV demonstrated good inter-observer variability scores (mean DSC 0.9) for both pre- and post-workshop. Post-workshop observer delineated cervix GTV was smaller than pre-workshop by 26.9%.

CONCLUSION

A radiologist-led workshop did not significantly reduce inter-observer variability in volume delineation for the three clinical sites. However, some improvement was noted in delineation of breast CTV, seroma volumes and cervix GTV.

The value of periprostatic fascia thickness and fascia preservation as prognostic factors of erectile function after nerve-sparing robot-assisted radical prostatectomy

PURPOSE

To determine the correlation of preoperative fascia thickness (FT) and intraoperative fascia preservation (FP) with erectile function (EF) after nerve-sparing robot-assisted radical prostatectomy (RARP).

METHODS

Our analysis included 106 patients, with localized prostate cancer and no erectile dysfunction (ED) before RARP, assessed with preoperative 3 Tesla (3 T) multiparametric magnetic resonance imaging (MRI). FP score was defined as the extent of FP from the base to the apex of the prostate, quantitatively assessed by the surgeon. Median fascia thickness (MFT) per patient was defined as the sum of the median FT of 12 MRI regions. Preserved MFT (pMFT) was the sum of the saved MFT. The percentage of pFMT (ppMFT) was also calculated. Fascia surface (FS) was measured on MRI and it was combined with FP score resulting in preserved FS (pFS) and percentage of pFS (ppFS).

RESULTS

FP score, pMFT, ppMFT, pFS and ppFS were significantly lower (p < 0.0001) in patients with ED. In the multivariate regression analysis, lower FP score [odds ratio (OR) 0.721, p = 0.03] and lower ppMFT (OR 0.001, p = 0.027) were independent predictors of ED. ROC analysis showed the highest area under the curve for ppMFT (0.787) and FP score (0.767) followed by pMFT (0.755) and ppFS (0.743).

CONCLUSIONS

MRI-determined periprostatic FT combined with intraoperative FP score are correlated to postprostatectomy EF. Based on the hypothesis that a thicker fascia forms a protective layer for the nerves, we recommend assessing FT preoperatively to counsel men for the odds of preserving EF after RARP.

Simulation as More Than a Treatment-Planning Tool: A Systematic Review of the Literature on Radiation Oncology Simulation-Based Medical Education

PURPOSE

Simulation-based medical education (SBME) is gaining prominence as a tool to meet Accreditation Council for Graduate Medical Education-mandated competency-based assessment educational goals. SBME is used in radiation oncology, although the type and extent are not clear. This study reports a systematic literature review designed to clarify the type and extent of radiation oncology SBME.

METHODS AND MATERIALS

The systematic review focused on radiation oncology SBME literature. The methods followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The inclusion criteria were identified according to the PICOS (population, intervention, comparison, outcome, and setting) framework. The population included undergraduate, graduate, and continuing medical education learners. Studies were limited to English-language studies published on or after January 1, 1990, in peer-reviewed journals. PubMed, MedEdPORTAL, and in-press articles were searched. The PubMed search was conducted using predefined search terms. References and similar articles were examined. Medical Subject Headings terms in selected articles were reviewed to ensure relevant terms were included.

RESULTS

Fifty-four SBME publications met the inclusion criteria. Only 9 of 54 studies (17%) self-identified as SBME. SBME types included screen-based simulators (56%), simulated environments (13%), virtual reality and haptic systems (13%), simulated patients (11%), part-task trainers (6%), and computer-based systems with mannequins (2%). A variety of radiation oncology skill sets were addressed, including contouring (54%), treatment planning (20%), clinical decision making (17%), anatomy and/or radiology (13%), radiation biology and/or physics (13%), communication skills and/or patient education (13%), brachytherapy (13%), and immobilization (11%). A target learning population was defined in 47 studies, including residents (53%), attending physicians (36%), medical students (21%), medical physicists (11%), radiation therapists (9%), nurses (6%), administrative staff (4%), and dosimetrists (4%). Learner feedback was reported in 32 studies.

CONCLUSIONS

Overall, this systematic literature review provides context and guidance for future radiation oncology SBME development. Appropriately framing SBME reports in the radiation oncology literature will facilitate development, implementation, and evaluation of SBME interventions. SBME resources should be centralized to facilitate dissemination and share resources.

Observer variation in the delineation of organs at risk for head and neck radiation therapy treatment planning: a systematic review protocol

REVIEW QUESTION

The objective of this review is to examine inter- and intra-observer agreement and reliability in the delineation of head and neck organs at risk (OAR) as part of the radiation therapy treatment planning process.More specifically, the objectives are to identify.

Short interactive workshops reduce variability in contouring treatment volumes for spine stereotactic body radiation therapy: Experience with the ESTRO FALCON programme and EduCase™ training tool

We report the results of 4, 2-h contouring workshops on target volume definition for spinal stereotactic radiotherapy. They combined traditional teaching methods with a web-based contouring/contour-analysis platform and led to a significant reduction in delineation variability. Short, interactive workshops can reduce interobserver variability in spine SBRT target volume delineation.

Uncertainties in volume delineation in radiation oncology: A systematic review and recommendations for future studies

BACKGROUND AND PURPOSE

Volume delineation is a well-recognised potential source of error in radiotherapy. Whilst it is important to quantify the degree of interobserver variability (IOV) in volume delineation, the resulting impact on dosimetry and clinical outcomes is a more relevant endpoint. We performed a literature review of studies evaluating IOV in target volume and organ-at-risk (OAR) delineation in order to analyse these with respect to the metrics used, reporting of dosimetric consequences, and use of statistical tests.

METHODS AND MATERIALS

Medline and Pubmed databases were queried for relevant articles using keywords. We included studies published in English between 2000 and 2014 with more than two observers.

RESULTS

119 studies were identified covering all major tumour sites. CTV (n=47) and GTV (n=38) were most commonly contoured. Median number of participants and data sets were 7 (3-50) and 9 (1-132) respectively. There was considerable heterogeneity in the use of metrics and methods of analysis. Statistical analysis of results was reported in 68% (n=81) and dosimetric consequences in 21% (n=25) of studies.

CONCLUSION

There is a lack of consistency in conducting and reporting analyses from IOV studies. We suggest a framework to use for future studies evaluating IOV.

Increasing consistency and accuracy in radiation therapy via educational interventions is not just limited to radiation oncologists

This editorial is advocating that increasing consistency and accuracy in radiation therapy via educational interventions is important for radiation therapist. Education and training with ongoing refreshers is the key to maintaining consistency throughout the radiotherapy process, which in turn will ensure all patients receive accurate treatment.

Quantitative assessment of target delineation variability for thymic cancers: Agreement evaluation of a prospective segmentation challenge

OBJECTIVES

We sought to quantitatively determine the inter-observer variability of expert radiotherapy target-volume delineation for thymic cancers, as part of a larger effort to develop an expert-consensus contouring atlas.

METHODS

A pilot dataset was created consisting of a standardized case presentation with pre- and post-operative DICOM CT image sets from a single patient with Masaoka-Koga Stage III thymoma. Expert thoracic radiation oncologists delineated tumor targets on the pre- and post-operative scans as they would for a definitive and adjuvant case, respectively. Respondents completed a survey including recommended dose prescription and target volume margins for definitive and post-operative scenarios. Inter-observer variability was analyzed quantitatively with Warfield's simultaneous truth, performance level estimation (STAPLE) algorithm and Dice similarity coefficient (DSC).

RESULTS

Seven users completed contouring for definitive and adjuvant cases; of these, 5 completed online surveys. Segmentation performance was assessed, with high mean±SD STAPLE-estimated segmentation sensitivity for definitive case GTV and CTV at 0.77 and 0.80, respectively, and post-operative CTV sensitivity of 0.55; all volumes had specificity of ≥0.99. Inter-observer agreement was markedly higher for the definitive target volumes, with mean±SD DSC of 0.88±0.03 and 0.89±0.04 for GTV and CTV respectively, compared to post-op CTV DSC of 0.69±0.06 (Kruskal-Wallis p<0.01.

CONCLUSION

Expert agreement for definitive case volumes was exceptionally high, though significantly lower agreement was noted post-operatively. Technique and dose prescription between experts was substantively consistent, and these preliminary results will be utilized to create an expert-consensus contouring atlas to aid the non-expert radiation oncologist in the planning of these challenging, rare tumors.

A Prostate Fossa Contouring Instructional Module: Implementation and Evaluation

PURPOSE/OBJECTIVE

Radiation oncology trainees frequently learn to contour through clinical experience and lectures. A hands-on contouring module was developed to teach delineation of the postoperative prostate clinical target volume (CTV) and improve contouring accuracy.

METHODS

Medical students independently contoured a prostate fossa CTV before and after receiving educational materials and live instruction detailing the RTOG approach to contouring this CTV. Metrics for volume overlap and surface distance (Dice similarity coefficient, Hausdorff distance (HD), and mean distance) determined discordance between student and consensus contours. An evaluation assessed perception of session efficacy (1 = "not at all" to 5 = "extremely"; reported as median[interquartile range]). Non-parametric statistical tests were used.

RESULTS

Twenty-four students at two institutions completed the module, and 21 completed the evaluation (88% response). The content was rated as "quite" important (4[3.5-5]). The module improved comfort contouring a prostate fossa (pre 1[1-2] vs. post 4[3-4], p<.01), ability to find references (pre 2[1-3] vs. post 4[3.5-4], p<0.01), knowledge of CT prostate/pelvis anatomy (pre 2[1.5-3] vs. post 3[3-4], p<.01), and ability to use contouring software tools (pre 2[2-3.5] vs. post 3[3-4], p=.01). After intervention, mean DSC increased (0.29 to 0.68, p<0.01) and HD and mean distance both decreased, respectively (42.8 to 30.0, p<.01; 11.5 to 1.9, p<.01).

CONCLUSIONS

A hands-on module to teach CTV delineation to medical students was developed and implemented. Student and expert contours exhibited near "excellent agreement" (as defined in the literature) after intervention. Additional modules to teach target delineation to all educational levels can be developed using this model.

Harmonization of the Volume of Interest Delineation among All Eleven Radiotherapy Centers in the North of France

Background

Inter-observer delineation variation has been detailed for many years in almost every tumor location. Inadequate delineation can impair the chance of cure and/or increase toxicity. The aim of our original work was to prospectively improve the homogeneity of delineation among all of the senior radiation oncologists in the Nord-Pas de Calais region, irrespective of the conditions of practice.

Methods

All 11 centers were involved. The first studied cancer was prostate cancer. Three clinical cases were studied: a low-risk prostate cancer case (case 1), a high-risk prostate cancer case (pelvic nodes, case 2) and a case of post-operative biochemical elevated PSA (case 3). All of the involved physicians delineated characteristically the clinical target volume (CTV) and organs at risk. The volumes were compared using validated indexes: the volume ratio (VR), common and additional volumes (CV and AV), volume overlap (VO) and Dice similarity coefficient (DSC). A second delineation of the same three cases was performed after discussion of the slice results and the choice of shared guidelines to evaluate homogenization. A comparative analysis of the indexes before and after discussion was conducted using the Wilcoxon test for paired samples. A p-value less than 0.05 was considered to indicate statistical significance.

Results

The indexes were not improved in case 1, for which the inter-observer agreement was considered good after the first comparison (DSC = 0.83±0.06). In case 2, the second comparison showed homogenization of the CTV delineation with a significant improvement in CV (81.4±11.7 vs. 88.6±10.26, respectively, p = 0.048), VO (0.41±0.09 vs. 0.47±0.07, respectively; p = 0.009) and DSC (0.58±0.09 vs. 0.63±0.07, respectively; p = 0.0098). In case 3, VR and AV were significantly improved: VR: 1.71(±0.6) vs. 1.34(±0.46), respectively, p = 0.0034; AV: 46.58(±14.50) vs. 38.08(±15.10), respectively, p = 0.0024. DSC was not improved, but it was already superior to 0.6 in the first comparison.

Conclusion

Our prospective work showed that a collaborative discussion about clinical cases and the choice of shared guidelines within an established framework improved the homogeneity of CTV delineation among the senior radiation oncologists in our region.

Integrating anatomy training into radiation oncology residency: considerations for developing a multidisciplinary, interactive learning module for adult learners

Radiation oncologists require an in-depth understanding of anatomical relationships for modern clinical practice, although most do not receive formal anatomy training during residency. To fulfill the need for instruction in relevant anatomy, a series of four multidisciplinary, interactive learning modules were developed for a cohort of radiation oncology and medical physics residents. Instructional design was based on established learning theories, with the intent of integrating knowledge of specific anatomical regions with radiology and radiation oncology practice. Each session included presentations by a radiologist and a radiation oncologist, as well as hands-on exploration of anatomical specimens with guidance from anatomists. Pre- and post-tests distributed during each session showed significant short-term knowledge retention. According to qualitative surveys and exit interviews, participants felt more comfort' with delineating structures, gross anatomy, and radiograph interpretation at the end of each session. Overall participant experience was positive, and the modules were considered effective for learning radiologic anatomy. Suggestions for future interventions include more time, increased clinical application, additional contouring practice and feedback, and improved coordination between each of the three disciplines. Results and conclusions from this study will be used to inform the design of a future multi-day national workshop for Canadian radiation oncology residents.

Evaluating the impact of a Canadian national anatomy and radiology contouring boot camp for radiation oncology residents

BACKGROUND

Radiation therapy treatment planning has advanced over the past 2 decades, with increased emphasis on 3-dimensional imaging for target and organ-at-risk (OAR) delineation. Recent studies suggest a need for improved resident instruction in this area. We developed and evaluated an intensive national educational course ("boot camp") designed to provide dedicated instruction in site-specific anatomy, radiology, and contouring using a multidisciplinary (MDT) approach.

METHODS

The anatomy and radiology contouring (ARC) boot camp was modeled after prior single-institution pilot studies and a needs-assessment survey. The boot camp incorporated joint lectures from radiation oncologists, anatomists, radiologists, and surgeons, with hands-on contouring instruction and small group interactive seminars using cadaveric prosections and correlative axial radiographs. Outcomes were evaluated using pretesting and posttesting, including anatomy/radiology multiple-choice questions (MCQ), timed contouring sessions (evaluated relative to a gold standard using Dice similarity metrics), and qualitative questions on satisfaction and perceived effectiveness. Analyses of pretest versus posttest scores were performed using nonparametric paired testing.

RESULTS

Twenty-nine radiation oncology residents from 10 Canadian universities participated. As part of their current training, 29%, 75%, and 21% receive anatomy, radiology, and contouring instruction, respectively. On posttest scores, the MCQ knowledge scores improved significantly (pretest mean 60% vs posttest mean 80%, P<.001). Across all contoured structures, there was a 0.20 median improvement in students' average Dice score (P<.001). For individual structures, significant Dice improvements occurred in 10 structures. Residents self-reported an improved ability to contour OARs and interpret radiographs in all anatomic sites, 92% of students found the MDT format effective for their learning, and 93% found the boot camp more effective than educational sessions at their own institutions. All of the residents (100%) would recommend this course to others.

CONCLUSIONS

The ARC boot camp is an effective intervention for improving radiation oncology residents' knowledge and understanding of anatomy and radiology in addition to enhancing their confidence and accuracy in contouring.

Technical guidelines for head and neck cancer IMRT on behalf of the Italian association of radiation oncology - head and neck working group

Performing intensity-modulated radiotherapy (IMRT) on head and neck cancer patients (HNCPs) requires robust training and experience. Thus, in 2011, the Head and Neck Cancer Working Group (HNCWG) of the Italian Association of Radiation Oncology (AIRO) organized a study group with the aim to run a literature review to outline clinical practice recommendations, to suggest technical solutions and to advise target volumes and doses selection for head and neck cancer IMRT. The main purpose was therefore to standardize the technical approach of radiation oncologists in this context. The following paper describes the results of this working group. Volumes, techniques/strategies and dosage were summarized for each head-and-neck site and subsite according to international guidelines or after reaching a consensus in case of weak literature evidence.

Development of a software for quantitative evaluation radiotherapy target and organ-at-risk segmentation comparison

Modern radiotherapy requires accurate region of interest (ROI) inputs for plan optimization and delivery. Target delineation, however, remains operator-dependent and potentially serves as a major source of treatment delivery error. In order to optimize this critical, yet observer-driven process, a flexible web-based platform for individual and cooperative target delineation analysis and instruction was developed in order to meet the following unmet needs: (1) an open-source/open-access platform for automated/semiautomated quantitative interobserver and intraobserver ROI analysis and comparison, (2) a real-time interface for radiation oncology trainee online self-education in ROI definition, and (3) a source for pilot data to develop and validate quality metrics for institutional and cooperative group quality assurance efforts. The resultant software, Target Contour Testing/Instructional Computer Software (TaCTICS), developed using Ruby on Rails, has since been implemented and proven flexible, feasible, and useful in several distinct analytical and research applications.

Prospective randomized double-blind study of atlas-based organ-at-risk autosegmentation-assisted radiation planning in head and neck cancer

BACKGROUND AND PURPOSE

Target volumes and organs-at-risk (OARs) for radiotherapy (RT) planning are manually defined, which is a tedious and inaccurate process. We sought to assess the feasibility, time reduction, and acceptability of an atlas-based autosegmentation (AS) compared to manual segmentation (MS) of OARs.

MATERIALS AND METHODS

A commercial platform generated 16 OARs. Resident physicians were randomly assigned to modify AS OAR (AS+R) or to draw MS OAR followed by attending physician correction. Dice similarity coefficient (DSC) was used to measure overlap between groups compared with attending approved OARs (DSC=1 means perfect overlap). 40 cases were segmented.

RESULTS

Mean ± SD segmentation time in the AS+R group was 19.7 ± 8.0 min, compared to 28.5 ± 8.0 min in the MS cohort, amounting to a 30.9% time reduction (Wilcoxon p<0.01). For each OAR, AS DSC was statistically different from both AS+R and MS ROIs (all Steel-Dwass p<0.01) except the spinal cord and the mandible, suggesting oversight of AS/MS processes is required; AS+R and MS DSCs were non-different. AS compared to attending approved OAR DSCs varied considerably, with a chiasm mean ± SD DSC of 0.37 ± 0.32 and brainstem of 0.97 ± 0.03.

CONCLUSIONS

Autosegmentation provides a time savings in head and neck regions of interest generation. However, attending physician approval remains vital.

Evaluating the impact of an integrated multidisciplinary head & neck competency-based anatomy & radiology teaching approach in radiation oncology: a prospective cohort study

BACKGROUND

Modern radiation oncology demands a thorough understanding of gross and cross-sectional anatomy for diagnostic and therapeutic applications. Complex anatomic sites present challenges for learners and are not well-addressed in traditional postgraduate curricula. A multidisciplinary team (MDT) based head-and-neck gross and radiologic anatomy program for radiation oncology trainees was developed, piloted, and empirically assessed for efficacy and learning outcomes.

METHODS

Four site-specific MDT head-and-neck seminars were implemented, each involving a MDT delivering didactic and case-based instruction, supplemented by cadaveric presentations. There was no dedicated contouring instruction. Pre- and post-testing were performed to assess knowledge, and ability to apply knowledge to the clinical setting as defined by accuracy of contouring. Paired analyses of knowledge pretests and posttests were performed by Wilcoxon matched-pair signed-rank test.

RESULTS

Fifteen post-graduate trainees participated. A statistically significant (p < 0.001) mean absolute improvement of 4.6 points (17.03%) was observed between knowledge pretest and posttest scores. Contouring accuracy was analyzed quantitatively by comparing spatial overlap of participants' pretest and posttest contours with a gold standard through the dice similarity coefficient. A statistically significant improvement in contouring accuracy was observed for 3 out of 20 anatomical structures. Qualitative and quantitative feedback revealed that participants were more confident at contouring and were enthusiastic towards the seminars.

CONCLUSIONS

MDT seminars were associated with improved knowledge scores and resident satisfaction; however, increased gross and cross-sectional anatomic knowledge did not translate into improvements in contouring accuracy. Further research should evaluate the impact of hands-on contouring sessions in addition to dedicated instructional sessions to develop competencies.

Clinical validation of atlas-based auto-segmentation of pelvic volumes and normal tissue in rectal tumors using auto-segmentation computed system

PURPOSE

To evaluate in two different settings - clinical practice and education/training - the reliability, time efficiency and the ideal sequence of an atlas-based auto-segmentation system in pelvic delineation of locally advanced rectal cancer.

METHODS

Fourteen consecutive patients were selected between October and December 2011. The images of four were used as an atlas and 10 used for validation. Two independent operators participated: a Delineator to contour and a Reviewer to perform an independent check (IC). The CTV, pelvic subsites and organs at risk were contoured in four different sequences. These included A: manual; B: auto-segmentation; C: auto-segmentation + manual revision; and D: manual + auto-segmentation + manual revision. Contouring was performed by the Delineator using the same planning CT. All of them underwent an IC by a Reviewer. The time required for all the contours were recorded and overlapping evaluation was assessed using a Dice coefficient.

RESULTS

In the clinical practice setting there have been 13 minutes time saved between sequences A versus sequences B (from 38 to 25 minutes, p = 0.002), a mean Dice coefficient in favor of sequences A for CTV and all subsites (p = 0.0195). In the educational/training setting there have been 35.2 minutes time saved between sequences C and D 8 (from 73.1 min to 37.9 min, p = 0.002).

CONCLUSION

The preliminary data suggest that the use of an atlas-based auto-contouring system may help improve efficiencies in contouring in the clinical practice setting and could have a tutorial role in the educational/training setting.

Prospective assessment of an atlas-based intervention combined with real-time software feedback in contouring lymph node levels and organs-at-risk in the head and neck: Quantitative assessment of conformance to expert delineation

PURPOSE

A number of studies have previously assessed the role of teaching interventions to improve organ-at-risk (OAR) delineation. We present a preliminary study demonstrating the benefit of a combined atlas and real time software-based feedback intervention to aid in contouring of OARs in the head and neck.

METHODS AND MATERIALS

The study consisted of a baseline evaluation, a real-time feedback intervention, atlas presentation, and a follow-up evaluation. At baseline evaluation, 8 resident observers contoured 26 OARs on a computed tomography scan without intervention or aid. They then received feedback comparing their contours both statistically and graphically to a set of atlas-based expert contours. Additionally, they received access to an atlas to contour these structures. The resident observers were then asked to contour the same 26 OARs on a separate computed tomography scan with atlas access. In addition, 6 experts (5 radiation oncologists specializing in the head and neck, and 1 neuroradiologist) contoured the 26 OARs on both scans. A simultaneous truth and performance level estimation (STAPLE) composite of the expert contours was used as a gold-standard set for analysis of OAR contouring.

RESULTS

Of the 8 resident observers who initially participated in the study, 7 completed both phases of the study. Dice similarity coefficients were calculated for each user-drawn structure relative to the expert STAPLE composite for each structure. Mean dice similarity coefficients across all structures increased between phase 1 and phase 2 for each resident observer, demonstrating a statistically significant improvement in overall OAR-contouring ability (P < .01). Additionally, intervention improved contouring in 16/26 delineated organs-at-risk across resident observers at a statistically significant level (P ≤ .05) including all otic structures and suprahyoid lymph node levels of the head and neck.

CONCLUSIONS

Our data suggest that a combined atlas and real-time feedback-based educational intervention detectably improves contouring of OARs in the head and neck.

Assessment and improvement of radiation oncology trainee contouring ability utilizing consensus-based penalty metrics

INTRODUCTION

The objective of this study was to develop and assess the feasibility of utilizing consensus-based penalty metrics for the purpose of critical structure and organ at risk (OAR) contouring quality assurance and improvement.

METHODS

A Delphi study was conducted to obtain consensus on contouring penalty metrics to assess trainee-generated OAR contours. Voxel-based penalty metric equations were used to score regions of discordance between trainee and expert contour sets. The utility of these penalty metric scores for objective feedback on contouring quality was assessed by using cases prepared for weekly radiation oncology radiation oncology trainee treatment planning rounds.

RESULTS

In two Delphi rounds, six radiation oncology specialists reached agreement on clinical importance/impact and organ radiosensitivity as the two primary criteria for the creation of the Critical Structure Inter-comparison of Segmentation (CriSIS) penalty functions. Linear/quadratic penalty scoring functions (for over- and under-contouring) with one of four levels of severity (none, low, moderate and high) were assigned for each of 20 OARs in order to generate a CriSIS score when new OAR contours are compared with reference/expert standards. Six cases (central nervous system, head and neck, gastrointestinal, genitourinary, gynaecological and thoracic) then were used to validate 18 OAR metrics through comparison of trainee and expert contour sets using the consensus derived CriSIS functions. For 14 OARs, there was an improvement in CriSIS score post-educational intervention.

CONCLUSIONS

The use of consensus-based contouring penalty metrics to provide quantitative information for contouring improvement is feasible.

Improving the identification of male pelvic structures in post-prostatectomy patients on cone-beam CT: a region of interest atlas study

Purpose: To investigate the benefits of a regions of interest atlas for radiation therapists (RTTs) to aid in the identification of male pelvic structures in radiotherapy for prostate cancer, post-prostatectomy.

Methods and materials: Recruiting 35 radiation therapists from the Royal North Shore Hospital, a pretest- post-test study design was employed, with the atlas as the intervention. Using two patient CT data-sets, structure identification was scored as correct or incorrect and RT confidence levels were recorded using a visual analogue scale. The number of years of experience of each RT was also documented. Statistical significance was calculated using the Wilcoxon signed ranks test, paired samples t-test and chi-square tests.

Results: A statistically significant improvement was found between the pre-test and post-test in terms of both structure identification (p < 0.001) and confidence (p < 0.001) levels, with use of the atlas. The atlas was of use to staff of varying experience levels. Structures that were not normally used for target volume localisation were the hardest to identify.

Conclusion: Regions of interest atlases should be implemented to help identification of areas of anatomical complexity.

Technical advances and pitfalls in head and neck radiotherapy

Intensity Modulated Radiotherapy (IMRT) is the standard of care in the treatment of head and neck squamous cell carcinomas (HNSCC) based on level 1 evidence. Technical advances in radiotherapy have revolutionized the treatment of HNSCC, with the most tangible gain being a reduction in long term morbidity. However, these benefits come with a serious and sobering price. Today, there is a greater chance of missing the target/tumor due to uncertainties in target volume definition by the clinician that is demanded by the highly conformal planning process involved with IMRT. Unless this is urgently addressed, our patients would be better served with the historically practiced non conformal radiotherapy, than IMRT which promises lesser morbidity. Image guided radiotherapy (IGRT) ensures the level of set up accuracy warranted to deliver a highly conformal treatment plan and should be utilized with IMRT, where feasible. Proton therapy has a theoretical physical advantage over photon therapy due to a lack of "exit dose". However, clinical data supporting the routine use of this technology for HNSCC are currently sparse. The purpose of this article is to review the literature, discuss the salient issues and make recommendations that address the gaps in knowledge.

Intensity-modulated radiotherapy in head and neck cancer: results of the prospective study GORTEC 2004-03

BACKGROUND AND PURPOSE

In 2003, the French Authority for Health (HAS) recommended the use of intensity modulated radiotherapy (IMRT) in prospective trial before its routine use. The Oncology and Radiotherapy Group for Head and Neck Cancer (GORTEC) proposed to evaluate prospectively acute and late toxicities, locoregional control and overall survival for patients treated for head and neck cancer (HNC) with IMRT and bilateral neck irradiation.

MATERIALS AND METHODS

Between 2002 and 2008, 208 patients with HNC were treated with IMRT in 8 centres. There were 38 nasopharynx, 117 oropharynx, 25 pharyngo-larynx, 24 oral cavity and 4 unknown primary (28.5% stage I-II and 71% Stage III-IV). Ninety-three patients (46%) had postoperative IMRT and 78 patients (37.5%) received concurrent chemotherapy. The doses were 70 Gy to the gross tumour, 66 Gy to the high-risk postoperative sites and 50 Gy to the subclinical disease. Toxicities were graded according to the RTOG-EORTC scales.

RESULTS

The median follow-up was 25.3 months (range: 0.4-72 months). There were 29 local-regional failures: 24 were in-field, three were marginal and one was out-field. The two-year loco-regional control and overall survival were 86% and 86.7%, respectively. At 18 months, grade ≥ 2 xerostomia was 16.1%. A mean dose to the spared parotid below 28 Gy led to significantly less grade ≥ 2 xerostomia (8.5% vs 24%) with a relative risk of 1.2 [95% CI: 1.02-1.41, p = 0.03]. Grade ≥ 2 xerostomia increased by approximately 3% per Gy of mean parotid dose up to 28, Gy then 7% per Gy above 33 Gy.

CONCLUSIONS

IMRT for HN cancer seems to reduce late toxicities without jeopardising local control and overall survival.

Human-computer interaction in radiotherapy target volume delineation: a prospective, multi-institutional comparison of user input devices

The purpose of this study was the prospective comparison of objective and subjective effects of target volume region of interest (ROI) delineation using mouse-keyboard and pen-tablet user input devices (UIDs). The study was designed as a prospective test/retest sequence, with Wilcoxon signed rank test for matched-pair comparison. Twenty-one physician-observers contoured target volume ROIs on four standardized cases (representative of brain, prostate, lung, and head and neck malignancies) twice: once using QWERTY keyboard/scroll-wheel mouse UID and once with pen-tablet UID (DTX2100, Wacom Technology Corporation, Vancouver, WA, USA). Active task time, ROI manipulation task data, and subjective survey data were collected. One hundred twenty-nine target volume ROI sets were collected, with 62 paired pen-tablet/mouse-keyboard sessions. Active contouring time was reduced using the pen-tablet UID, with mean ± SD active contouring time of 26 ± 23 min, compared with 32 ± 25 with the mouse (p ≤ 0.01). Subjective estimation of time spent was also reduced from 31 ± 26 with mouse to 27 ± 22 min with the pen (p = 0.02). Task analysis showed ROI correction task reduction (p = 0.045) and decreased panning and scrolling tasks (p < 0.01) with the pen-tablet; drawing, window/level changes, and zoom commands were unchanged (p = n.s.) Volumetric analysis demonstrated no detectable differences in ROI volume nor intra- or inter-observer volumetric coverage. Fifty-two of 62 (84%) users preferred the tablet for each contouring task; 5 of 62 (8%) denoted no preference, and 5 of 62 (8%) chose the mouse interface. The pen-tablet UID reduced active contouring time and reduced correction of ROIs, without substantially altering ROI volume/coverage.

Delineation in thoracic oncology: a prospective study of the effect of training on contour variability and dosimetric consequences

Introduction

As part of French residents' radiotherapy training, delineation workstations were available at a national teaching course. We report a prospective comparative study of a non small cell lung cancer (NSCLC) case delineated by 120 residents before and after a radioanatomy/radiotherapy lecture.

Materials and methods

The case of a patient with right upper lobe non small cell lung cancer (NSCLC) was provided for delineation to 32 groups of residents before and after a radiation therapy lecture about thoracic delineation. GTV, CTV and PTV was asked to each group. In a second step, the GTV, CTV and PTV were compared with those of 9 groups of senior physicians. Finally the consequences for treatment planning between each group before and after the course were explored.

Results

The expert's average GTV, CTV and PTV were 89.1 cm³, 242.3 cm³ and 293.9 cm³ respectively. For residents, those volumes were 103.4 cm³, 242.3 cm³ and 457.9 cm³ before teaching, compared to 99.5 cm³, 224.2 cm³ and 412.5 cm³ after teaching. The overlap (OV) and kappa (KI) indices before and after education were respectively 0.58 and 0.73. Compared to senior physicians, OV and KI indices were lower in the residents group (p = 0.039 and p = 0.043). An increased dose to the lung is noted for the residents' dosimetry compared to the experts' (V20: 23.2% versus 36.5%) due to the larger PTV delineated. No significant difference was observed for other organs at risk.

Conclusion

There were no significant differences for the delineation of the GTV and CTV before and after the course, although the differences tended to decrease after the course. The good initial quality of the contours could explain the lack of difference. V20 for lung was higher in the residents group compared to the experts group (23.2% vs 36.5%). No other treatment planning consequences were observed for other critical organs.

Evaluation of tomotherapy MVCT image enhancement program for tumor volume delineation

The aims of this study were to investigate the variability between physicians in delineation of head and neck tumors on original tomotherapy megavoltage CT (MVCT) studies and corresponding software enhanced MVCT images, and to establish an optimal approach for evaluation of image improvement. Five physicians contoured the gross tumor volume (GTV) for three head and neck cancer patients on 34 original and enhanced MVCT studies. Variation between original and enhanced MVCT studies was quantified by DICE coefficient and the coefficient of variance. Based on volume of agreement between physicians, higher correlation in terms of average DICE coefficients was observed in GTV delineation for enhanced MVCT for patients 1, 2, and 3 by 15%, 3%, and 7%, respectively, while delineation variance among physicians was reduced using enhanced MVCT for 12 of 17 weekly image studies. Enhanced MVCT provides advantages in reduction of variance among physicians in delineation of the GTV. Agreement on contouring by the same physician on both original and enhanced MVCT was equally high.

PACS numbers: 87.57.N‐, 87.57.np, 87.57.nt

Atlas-based semiautomatic target volume definition (CTV) for head-and-neck tumors

PURPOSE

To develop a new semiautomatic method to improve target delineation in head-and-neck cancer.

METHODS AND MATERIALS

We implemented an atlas-based software program using fourteen anatomic landmarks as well as the most superior and inferior computerd tomography slices for automatic target delineation, using an advanced laryngeal carcinoma as an example. Registration was made by an affine transformation. Evaluation was performed with manually drawn contours for comparison. Three physicians sampled and further applied a target volume atlas to ten other computer tomography data sets. In addition, a rapid three-dimensional (3D) correction program was developed.

RESULTS

The mean time to the first semiautomatic target delineation proposal was 2.7 minutes. Manual contouring required 20.2 minutes per target, whereas semiautomatic target volume definition with the rapid 3D correction was completed in only 9.7 minutes. The net calculation time for image registration of the target volume atlas was negligible (approximately 0.6 seconds). Our method depicted a sufficient adaptation of the target volume atlas on the new data sets, with a mean similarity index of 77.2%. The similarity index increased up to 85% after 3D correction performed by the physicians.

CONCLUSIONS

We have developed a new, feasible method for semiautomatic contouring that saves a significant amount (51.8%) of target delineation time for head-and-neck cancer patients. This approach uses a target volume atlas and a landmark model. The software was evaluated by means of laryngeal cancer but has important implications for various tumor types whereby target volumes remain constant in form and do not move with respiration.