Importance of training in external beam treatment planning for locally advanced cervix cancer: Report from the EMBRACE II dummy run

doi:10.1016/j.radonc.2019.01.012

Radiotherapy and Oncology

Volume 133, April 2019, Pages 149-155

https://doi.org/10.1016/j.radonc.2019.01.012 Get rights and content

Highlights

•
Establish EBRT treatment planning compliance through a dummy-run (EMBRACE II).
•
Plan quality development after introducing novel EBRT planning concepts.
•
Individual feedback improves EBRT plan quality and inter-center consistency.

Abstract

Background and purpose

The EMBRACE II study combines state-of-the-art Image-Guided Adaptive Brachytherapy in cervix cancer with an advanced protocol for external beam radiotherapy (EBRT) which specifies target volume selection, contouring and treatment planning. In EMBRACE II, well-defined EBRT is an integral part of the overall treatment strategy with the primary aim of improving nodal control and reducing morbidity. The EMBRACE II EBRT planning concept is based on improved conformality through relaxed coverage criteria for all target volumes. For boosting of lymph nodes, a simultaneous integrated boost and coverage probability planning is applied. Before entering EMBRACE II, institutes had to go through accreditation.

Material and methods

As part of accreditation, a treatment planning dummy-run included educational blocks and submission of an examination case provided by the study coordinators. Seventy-one centers submitted 123 EBRT dose distributions. Replanning was required if hard constraints were violated or planning concepts were not fully accomplished. Dosimetric parameters of original and revised plans were compared.

Results

Only 11 plans violated hard constraints. Twenty-seven centers passed after first submission. 27 needed one and 13 centers needed more revisions. The most common reasons for revisions were low conformality, relatively high OAR doses or insufficient lymph node coverage reduction. Individual feedback on planning concepts improved plan quality considerably, resulting in a median body V43Gy reduction of 158 cm³ from first plan submission to approved plan.

Conclusion

A dummy-run as applied in EMBRACE II, consisting of training and examination cases enabled us to test institutes’ treatment planning capabilities, and improve plan quality.

Section snippets

Materials and methods

The EMBRACE II study was initiated in 2016, and by August 2018, 10 institutions had accrued 235 patients. It includes patients with histologically proven cancer of the uterine cervix, FIGO stage IB-IVB considered suitable for curative treatment with definitive radiochemotherapy and MRI guided brachytherapy.

EBRT target definition [7], [8] was based on MRI and CT and included: initial GTV, initial High-Risk and Low-Risk CTV-T (Tumor) and internal target volume (ITV-T). The elective nodal target

Results

By December 2018, 71 institutes had completed submission of which, at this time point, 67 EBRT plans were approved. IMRT, VMAT and tomotherapy were used in 7%, 88% and 5% of the centers, and 6, 10 and 15 MV in 71%, 24% and 5% of centers, respectively. It was possible to produce acceptable plans with all techniques, energies, and treatment planning systems. Eleven submitted plans (15%) violated hard constraints.

After first submission, 27 plans were directly approved, 27 plans after one feedback

Discussion

Training, monitoring and early intervention in case of discrepancies is valuable to achieve a high consistency in plan quality among centers in multicenter trials – not only in measurable parameters but also in concept. This helps avoidance of protocol deviations that can lead to decrease of tumor control [20] or suboptimal planning that can lead to increased complication risk [21].

This analysis shows that even with a strict EBRT protocol there were significant variations in planning approach

Conflict of interest

The EMBRACE studies are supported by Varian Medical Systems and Elekta. The financial support by the Austrian Federal Ministry for Digital, Business and Enterprise and the National Foundation for Research, Technology and Development is gratefully acknowledged.

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Cited by (13)

ESGO/ESTRO quality indicators for radiation therapy of cervical cancer
2023, Radiotherapy and Oncology
The European Society of Gynaecological Oncology (ESGO) has previously defined and established a list of quality indicators for the surgical treatment of cervical cancer. As a continuation of this effort to improve overall quality of care for cervical cancer patients across all aspects, ESGO and the European SocieTy for Radiotherapy and Oncology (ESTRO) initiated the development of quality indicators for radiation therapy of cervical cancer.
To develop a list of quality indicators for radiation therapy of cervical cancer that can be used to audit and improve clinical practice by giving to practitioners and administrators a quantitative basis to improve care and organizational processes, notably for recognition of the increased complexity of modern external radiotherapy and brachytherapy techniques.
Quality indicators were based on scientific evidence and/or expert consensus. The development process included a systematic literature search for identification of potential quality indicators and documentation of scientific evidence, consensus meetings of a group of international experts, an internal validation process, and external review by a large international panel of clinicians (n = 99).
Using a structured format, each quality indicator has a description specifying what the indicator is measuring. Measurability specifications are detailed to define how the quality indicators will be measured in practice. Targets were also defined for specifying the level which each unit or center should be aiming to achieve. Nineteen structural, process, and outcome indicators were defined. Quality indicators 1–6 are general requirements related to pretreatment workup, time to treatment, upfront radiation therapy, and overall management, including active participation in clinical research and the decision making process within a structured multidisciplinary team. Quality indicators 7–17 are related to treatment indicators. Quality indicators 18 and 19 are related to patient outcomes.
This set of quality indicators is a major instrument to standardize the quality of radiation therapy in cervical cancer. A scoring system combining surgical and radiotherapeutic quality indicators will be developed within an envisaged future ESGO accreditation process for the overall management of cervical cancer, in an effort to support institutional and governmental quality assurance programs.
Plan quality association between dummy run and individual case review in a prospective multi-institutional clinical trial of postoperative cervical cancer patients treated with intensity-modulated radiotherapy: Japan clinical Oncology Group study (JCOG1402)
2023, Radiotherapy and Oncology
The Japan Clinical Oncology Group (JCOG) 1402 conducted a multicenter clinical trial of postoperative intensity-modulated radiotherapy (IMRT) for high-risk uterine cervical cancer patients. We assess effectiveness of the quality assurance (QA) program in central review through dummy runs (DRs) performed before patient enrollment and post-treatment individual case review (ICR), and clarify the pitfalls in treatment planning.
The ICRs were conducted using the same QA program as the DR for 214 plans. The deviations were compared with those demonstrated in the DRs, and the pitfalls were clarified. Fifteen face-to-face meetings were held with physicians at participating institutions to provide feedback.
Two-hundred and eighty-eight deviations and nine violations were detected in the 214 plans. The patterns of the deviations observed in the ICRs were similar to that in the DR. Frequent deviations were observed in clinical target volume (CTV) delineations, 50% in the DRs and 37% in the ICRs, respectively. In the ICRs, approximately 1.4 deviations/violations were observed per plan, which was lower than DR. Nine violations included inaccurate CTV delineation and improper PTV (planning target volume) margin, which had risks in loco-regional failures by inadequate dose coverage.
Our developed QA program commonly used in DR and ICR clarified the pitfalls in treatment plans. Although the frequent deviations in CTV delineations were observed in the ICR, the deviations decreased compared to that in the DR. More specified face-to-face meetings with participating institutions will be necessary to maintain the quality of IMRT in the clinical protocol.
Multi-center dosimetric predictions to improve plan quality for brachytherapy for cervical cancer treatment
2023, Radiotherapy and Oncology
Image-guided adaptive brachytherapy (IGABT) is an important modality in the cervical cancer treatment, and plan quality is sensitive to time pressure in the workflow. Patient anatomy-based quality-assurance (QA) with overlap volume histograms (OVHs) has been demonstrated to detect suboptimal plans (outliers). This analysis quantifies the possible improvement of plans detected as outliers, and investigates its suitability as a clinical QA tool in a multi-center setting.
In previous work OVH-based models were investigated for the use of QA. In this work a total of 160 plans of 68 patients treated in accordance with the current state-of-the-art IGABT protocol from Erasmus MC (EMC) were analyzed, with a model based on 120 plans (60 patients) from UMC Utrecht (UMCU). Machine-learning models were trained to define QA thresholds, and to predict dose D_2cm3 to bladder, rectum, sigmoid and small bowel with the help of OVHs of the EMC cohort. Plans out of set thresholds (outliers) were investigated and retrospectively replanned based on predicted D_2cm3 values.
Analysis of replanned plans demonstrated a median improvement of 0.62 Gy for all Organs At Risk (OARs) combined and an improvement for 96 % of all replanned plans. Outlier status was resolved for 36 % of the replanned plans. The majority of the plans that could not be replanned were reported having implantation complications or insufficient coverage due to tumor geometry.
OVH-based QA models can detect suboptimal plans, including both unproblematic BT applications and suboptimal planning circumstances in general. OVH-based QA models demonstrate potential for clinical use in terms of performance and user-friendliness, and could be used for knowledge transfer between institutes. Further research is necessary to differentiate between (sub)optimal planning circumstances.
Multi-center analysis of machine-learning predicted dose parameters in brachytherapy for cervical cancer
2022, Radiotherapy and Oncology
Image-guided adaptive brachytherapy (IGABT) is a key component in the treatment of cervical cancer, but the nature of the clinical workflow makes it vulnerable to suboptimal plans, as the theoretical optimal plan depends heavily on organ configuration. Patient anatomy-based quality-assurance (QA) with overlap volume histograms (OVHs) is a promising tool to detect such suboptimal plans, and in this analysis its suitability as a multi-institutional clinical QA tool is investigated.
A total of 223 plans of 145 patients treated in accordance with the current state-of-the-art IGABT protocols from UMC Utrecht (UMCU) and Erasmus MC (EMC) were included. Machine-learning models were trained to predict dose D_2cm3 to bladder, rectum, sigmoid and small bowel with the help of OVHs. For this strategy, points are sampled on the organs-at-risk (OARs), and the distances of the sampled points to the target are computed and combined in a histogram. Machine-learning models can then be trained to predict dose-volume histograms (DVHs) for unseen data. Single-center model robustness to needle use and applicator type and multi-center model translatability were investigated. Performance of models was assessed by the difference between planned (clinical) and predicted D_2cm3 values.
Intra-validation of UMCU data demonstrated OVH model robustness to needle use and applicator type. The model trained on UMCU data was found to be robust within the same protocol on EMC data, for all investigated OARs. Mean squared error between planned and predicted D_2cm3 values of OARs ranged between 0.13 and 0.40 Gy within the same protocol, indicating model translatability. For the former protocol cohort of Erasmus MC large deviations were found between the planned and predicted D_2cm3 values, indicating plan deviation from protocol. Mean squared error for this cohort ranged from 0.84 to 4.71 Gy.
OVH-based models can provide a solid basis for multi-institutional QA when trained on a sufficiently strict protocol. Further research will quantify the model’s impact as a QA tool.
Adaptive Radiotherapy in the Management of Cervical Cancer: Review of Strategies and Clinical Implementation
2021, Clinical Oncology
Citation Excerpt :
A recent study comparing two deep learning methods validated on 255 CT scans of patients treated for locally advanced cervical cancer showed good concordance between clinician and AI contouring [84]. However, to facilitate the use of AI contouring and automated plan optimisation, standardisation of contour delineation is required [85,86] together with appropriate quality assurance procedures for these techniques [87,88]. One of the benefits of daily oART for gynaecological cancers is that the inter-fractional anatomic movement is accounted for; as such a reduction of the PTV margin should be achievable.
The complex and varied motion of the cervix–uterus target during external beam radiotherapy (EBRT) underscores the clinical benefits afforded by adaptive radiotherapy (ART) techniques. These gains have already been realised in the implementation of image-guided adaptive brachytherapy, where adapting to anatomy at each fraction has seen improvements in clinical outcomes and a reduction in treatment toxicity. With regards to EBRT, multiple adaptive strategies have been implemented, including a personalised internal target volume, offline replanning and a plan of the day approach. With technological advances, there is now the ability for real-time online ART using both magnetic resonance imaging and computed tomography-guided imaging. However, multiple challenges remain in the widespread dissemination of ART. This review investigates the ART strategies and their clinical implementation in EBRT delivery for cervical cancer.
Impact of transitioning to an online course – A report from the ESTRO gyn teaching course
2021, Clinical and Translational Radiation Oncology
Citation Excerpt :
The homework for radiation/clinical oncologists (RO/CO) involved contouring on one EBRT case and one IGABT case using the ESTRO FALCON/EduCase platform [17]. For medical physicists (MP), the homework involved downloading DICOM datasets for one EBRT case and one IGABT case for dose planning in their own clinical software and submitting their results in an Excel spreadsheet, a process that was successfully used for accreditation in the EMBRACE-II study [14]. Approximately 64% of the synchronous sessions (21/33 h) were dedicated to lectures while 33% (11/33 h) were interactive activities including hands-on practical workshops.
In 2020, the ESTRO course on image-guided radiotherapy and chemotherapy in gynaecological cancer was converted into an online version due to the COVID-19 pandemic. This paper describes the change process and evaluates the impact on participants compared with previous live courses.
The 2019 live course contained 41 h of educational content, comprising 33 h of synchronous activities (lectures, interactive activities, videos) and 8 h of homework (contouring, dose planning). For the online course, the lectures were provided as pre-course material (11 mandatory, 22 optional). Contouring/dose planning homework was unchanged. The synchronous sessions were reconfigured as six 2-hour webinars (total educational content ~38 h).
Participant numbers/characteristics, engagement and satisfaction for six live courses and the online course were compared.
Participant numbers for the online and live courses were similar (90 vs. mean 96). There were more participants from outside Europe (28% vs. mean 18%) and more non-doctors (47% vs. mean 33%). Proportion of participants responding to the pre-course questionnaire was similar (77% vs. mean 78%) but post-course questionnaire response was lower (62% vs. mean 92%).
43% participants viewed ≥75% of mandatory lectures before the webinars. 86% viewed the optional lectures. Submissions of contouring and dose planning homework was higher (contouring 77%–90% vs. 56%–69%, dose planning 74%–89% vs. 29%–57%).
96% (47/49) participants rated the online course as Excellent (43%) or Good (53%). Overall satisfaction was similar (4.4 vs. mean 4.6).
Participant satisfaction and engagement with the online course remained high despite less contact time with faculty.

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Orignal ArticleImportance of training in external beam treatment planning for locally advanced cervix cancer: Report from the EMBRACE II dummy run

Highlights

Abstract

Background and purpose

Material and methods

Results

Conclusion

Section snippets

Materials and methods

Results

Discussion

Conflict of interest

Radiother Oncol

Brachytherapy

Brachytherapy

Radiother Oncol

Radiother Oncol

Clin Transl Radiat Oncol

Int J Radiat Oncol

Radiother Oncol

Radiother Oncol

Radiother Oncol

Radiother Oncol

Radiother Oncol

Brachytherapy

Radiother Oncol

Radiother Oncol

Radiother Oncol

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol

Int J Radiat Oncol

Cancer/Radiothérapie

Orignal Article
Importance of training in external beam treatment planning for locally advanced cervix cancer: Report from the EMBRACE II dummy run