Interobserver variability (between radiation oncologist and radiation therapist) in tumor bed contouring after breast-conserving surgery

An Environmental Scan of Advanced Practice Radiation Therapy in the United States: A PESTEL Analysis

PURPOSE

In 2021, the Advanced Practice Radiation Therapy Working Group (APRTWG) was established in the United States as a grassroots alliance of multidisciplinary radiation oncology professionals-radiation therapists, physicians, dosimetrists, and administrators-located across the country, interested in studying and establishing the Advanced Practice Radiation Therapist (APRT) level of practice in the United States. The APRT model has shown success in the United Kingdom, Canada, Australia, Singapore, and other countries, documenting the value of the APRT to the quality and advancement of clinical care. In the United States, the APRTWG seeks to coordinate activities, align resources, and drive the national agenda to collectively develop and define novel models of care using APRT in line with the evolving needs of patients and the radiation therapy profession. This environmental scan aims to examine the context of radiation oncology medical practice in the United States to inform pathways ahead for a proposed APRT model through a Political, Economic, Social, Technological, Environmental, and Legal (PESTEL) analysis.

METHODS AND MATERIALS

A literature search was conducted to understand the chronological timeline of the development of APRT during the past 25 years. Items that included the activities, scope of practice, and implementation of APRT nationally and internationally were identified. Papers describing advanced practitioner roles that are commonly found in the multidisciplinary team in radiation oncology both in the United States and internationally, such as physician assistants and nurse practitioners, were excluded.

RESULTS

Despite the environmental scan outcome, it is acknowledged that data collation and analysis was not as robust as that anticipated by undertaking a systematic review. Papers were identified by the lead author that aligned with each of the PESTEL factors. Defined broadly, a new care model can adjust how health services are delivered by incorporating best practices in patient care for a specific population, person, or patient cohort. As patients enter different stages of their disease, the purpose of a new model is to provide individuals with the right care, at the right time, by the right team, in the right place. It is clear that the opportunity for positive change and impact on the current state of practice in radiation oncology exists.

CONCLUSION

The environmental scan findings demonstrate the complexities associated with implementing APRT in the United States, with multifactorial political, environmental, societal, technological, economic, and legal aspects to consider. The APRTWG will continue to lead and participate in such activities to demonstrate and identify APRT role opportunities in the United States and drive the nationwide implementation of the APRT level of practice in this country.

Assessing Interobserver Variability in the Delineation of Structures in Radiation Oncology: A Systematic Review

PURPOSE

The delineation of target volumes and organs at risk is the main source of uncertainty in radiation therapy. Numerous interobserver variability (IOV) studies have been conducted, often with unclear methodology and nonstandardized reporting. We aimed to identify the parameters chosen in conducting delineation IOV studies and assess their performances and limits.

METHODS AND MATERIALS

We conducted a systematic literature review to highlight major points of heterogeneity and missing data in IOV studies published between 2018 and 2021. For the main used metrics, we did in silico analyses to assess their limits in specific clinical situations.

RESULTS

All disease sites were represented in the 66 studies examined. Organs at risk were studied independently of tumor site in 29% of reviewed IOV studies. In 65% of studies, statistical analyses were performed. No gold standard (GS; ie, reference) was defined in 36% of studies. A single expert was considered as the GS in 21% of studies, without testing intraobserver variability. All studies reported both absolute and relative indices, including the Dice similarity coefficient (DSC) in 68% and the Hausdorff distance (HD) in 42%. Limitations were shown in silico for small structures when using the DSC and dependence on irregular shapes when using the HD. Variations in DSC values were large between studies, and their thresholds were inconsistent. Most studies (51%) included 1 to 10 cases. The median number of observers or experts was 7 (range, 2-35). The intraclass correlation coefficient was reported in only 9% of cases. Investigating the feasibility of studying IOV in delineation, a minimum of 8 observers with 3 cases, or 11 observers with 2 cases, was required to demonstrate moderate reproducibility.

CONCLUSIONS

Implementation of future IOV studies would benefit from a more standardized methodology: clear definitions of the gold standard and metrics and a justification of the tradeoffs made in the choice of the number of observers and number of delineated cases should be provided.

Online adaptive MR-guided radiotherapy: Conformity of contour adaptation for prostate cancer, rectal cancer and lymph node oligometastases among radiation therapists and radiation oncologists

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Contour adaptation conformity analyzed for LN-metastases, rectal- + prostate cancer.

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Contour adaptation conformity among RTTs and radiation oncologists is comparable.

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Role expansion of RTTs with daily contour adaptation impacts workflow efficiency.

Background and purpose

Online adaptive MR-guided treatment planning workflows facilitate daily contour adaptation to the actual anatomy. Allocating contour adaptation to radiation therapists (RTTs) instead of radiation oncologists (ROs) might allow for increasing workflow efficiency. This study investigates conformity of adapted target contours provided by dedicated RTTs and ROs.

Materials and methods

In a simulated online procedure, 6 RTTs and 6 ROs recontoured targets and organs at risk (OAR) in prostate cancer (n = 2), rectal cancer (n = 2) and lymph node-oligometastases (n = 2) cases. RTTs gained contouring competence beforehand by following a specific in-house training program. For all target contours and the reference delineations volumetric differences were determined and Dice similarity coefficient (DSC), conformity index (CI) and generalized CI were calculated. Delineation time and –confidence were registered for targets and OAR. Impact of contour adaptation on treatment plan quality was investigated.

Results

Delineation conformity was generally high with DSC, CI and generalized CI values in the range of 0.81–0.94, 0.87–0.95 and 0.63–0.85 for prostate cancer, rectal cancer and LN-oligometastasis, respectively. Target volumes were comparable for both, RTTs and ROs. Time needed and confidence in contour adaptation was comparable as well. Treatment plans derived with adapted contours did not violate dose volume constrains as used in clinical routine.

Conclusion

After tumor site specific training, daily contour adaptations as needed in adaptive online radiotherapy workflows can be accurately performed by RTTs. Conformity of the derived contours is high and comparable to contours as provided by ROs.

Advanced practice roles of therapeutic radiographers/radiation therapists: A systematic literature review

INTRODUCTION

Advances in Radiotherapy (RT) technology and increase of complexity in cancer care have enabled the implementation of new treatment techniques. Subsequently, a greater level of autonomy, responsibility, and accountability in the practice of Therapeutic Radiographers/Radiation Therapists (TR/RTTs) has led to Advanced Practice (AP) roles. The published evidence of this role is scattered with confusing terminology and divergence regarding the perception of whether a specific role represents AP internationally. This study aims to establish an international baseline of evidence on AP roles in RT to identify roles and activities performed by TR/RTTs at advanced level practice and to summarise the impact.

METHODS

A systematic PRISMA review of the literature was undertaken. Thematic analysis was used to synthesise the roles and associated activities. Six RT external experts validated the list. The impact was scrutinised in terms of clinical, organisational, and professional outcomes.

RESULTS

Studies (n = 87) were included and categorised into four groups. AP roles were listed by clinical area, site-specific, and scope of practice, and advanced activities were organised into seven dimensions and 27 sub-dimensions. Three most-reported outcomes were: enhanced service capacity, higher patient satisfaction, and safety maintenance.

CONCLUSION

Evidence-based AP amongst TR/RTTs show how AP roles were conceptualised, implemented, and evaluated. Congruence studies have shown that TR/RTTs are at par with the gold-standard across the various AP roles.

IMPLICATIONS FOR PRACTICE

This is the first systematic literature review synthetisising AP roles and activities of TR/RTTs. This study also identified the main areas of AP that can be used to develop professional frameworks and education guiding policy by professional bodies, educators and other stakeholders.

Evaluation of delineating the target volume by radiation therapists in breast cancer patients

Aim

Breast radiotherapy accounts for a significant workload in radiotherapy departments. In 2015 it became clinical practice at the Netherlands Cancer Institute for radiation therapists (RTTs) to delineate the clinical target volume of the breast tissue (CTVbreast) and in 2017 axilla level I-II (CTVln12) according to a delineation atlas. All RTTs were trained and got individual feedback. The aim of this retrospective study was to investigate the variation between the CTVbreast with or without CTVln12 delineated by a trained group of radiation therapists and the clinical adjusted delineations by the radiation oncologist/physician assistant (RO/PA), in a large group of patients treated between January 2017 and June 2020.

Materials and Methods

1012 computer tomography based delineations of CTVbreast and 146 of CTVln12 were collected from January 2017-June 2020. The RTT and RO/PA delineations were compared using the Dice coefficient and the 95th percentile Hausdorff Distance (95%HD). Statistical significance of the differences was tested using a Mann-Whitney test.

Results

Differences in CTVbreast delineations were small. A median Dice score of 1.00 for all years, where 83% of the patients had a Dice score > 0.99. For CTVln12 the magnitude of edits made by RO/PAs decreased over time, with the Dice increasing from a median of 0.87 in 2017 to 0.90 in 2020 (p = 0.031). The 95%HD decreased from a median of 0.93 cm in 2017 to 0.61 cm in 2020 (p = 0.051).

Conclusions

This retrospective study shows that trained dedicated RTTs are capable in delivering the same quality delineations as RO/PAs. The low variability supports the increasing role of RTTs in the contouring process, likely making it more time efficient.

Radiation therapy technologists' involvement and opinion in research: A national survey in Italy

Introduction

This survey describes Italian RTTs' involvement and opinions in research activities related to radiation oncology. Primary aim was to assess the degree of involvement of the national RTTs community in research and to describe how RTTs can integrate their skills collaborating with other professionals.

Materials and methods

A ten-items multiple-choice questionnaire, with 2-8 possible responses, was developed by a steering committee and generated on a survey platform. Links were sent via email to Italian RTTs.The questions were divided in 3 domains: demographic data; scientific research and activity; opinions about RTTs role in scientific research. The survey started on October 1, 2018 and ended on January 31, 2019.

Results

One hundred thirty-five out of 509 (26.5%) RTTs responded to the questionnaire at its expiring date; 97.73% think to be valid contributors in radiation oncology research, expressing clear interest in "data collection" tasks (52.71%); 38.64% feel unsupported by other professionals in the research team and 59.85% of the respondents are not members in any scientific society.

Conclusions

The role of Italian RTTs in research is heterogeneous. Mainly RTTs in the age range from 30 to 40 years responded to the survey showing their interest in scientific research. This might be related to different informatics and educational skills as well as to personal attitudes. RTTs particular skills, like data management and technical hypothesis generation abilities, are of benefit to realize research projects. Therefore, engaging RTTs in research activities is strongly suggested.