The impact of training and professional collaboration on the interobserver variation of lung cancer delineations: a multi-institutional study

Clinical target volume automatic segmentation based on lymph node stations for lung cancer with bulky lump lymph nodes

Background

The lack of standardized delineation of lymph node station in lung cancer radiotherapy leads to nonstandard clinical target volume (CTV) contouring, especially in patients with bulky lump gross target volume lymph nodes (GTVnd). This study defines lymph node region boundaries in radiotherapy for lung cancer and automatically contours lymph node stations based on the International Association for the Study of Lung Cancer (IASLC) lymph node map.

Methods

Computed tomography (CT) scans of 200 patients with small cell lung cancer were collected. The lymph node zone boundaries were defined based on the IASLC lymph node map, with adjustments to meet radiotherapy requirements. Contours of lymph node stations were confirmed by two experienced oncologists. A model (DiUNet) was constructed by incorporating the contours of GTVnd to precisely contour the boundaries. Quantitative evaluation metrics and clinical evaluations were conducted.

Results

The mean 3D Dice similarity coefficient (Dice similarity coefficient) values of DiUNet in most lymph node stations was greater than 0.7, 98.87% of the lymph node station slices are accepted. The mean DiUNet score was not significantly different from that of the man contoured in the evaluation of lymph node stations and CTV.

Conclusion

This is the first study to propose a method that automatically contours lymph node regions station by station based on the IASLC lymph node map with bulky lump GTVnd. Delineation of lymph node stations based on the DiUNet model is a promising strategy to obtain accuracy and efficiency for CTV delineation in lung cancer patients, especially for bulky lump GTVnd.

Developing a Feasible and Credible Method for Analyzing Healthcare Documents as Written Data

Healthcare provides a rich, and constantly increasing, number of written documents, which are underutilized in research data for health and nursing sciences, but previous literature has only provided limited guidance on the process of document analysis. The aim of this paper is to provide a methodological framework for analyzing health care documents as written data, based on a systematic methodological review and the research team’s experience of the method. Based on the results, the methods consist of seven phases: (i) identify the purpose, (ii) determine the document selection strategy, (iii) select or design an extraction matrix, (iv) carry out pilot testing, (v) collect and analyze the data, (vi) consider the credibility, and (vii) ethics of the study. The framework that has been developed can be used to carry out document analysis studies that are both feasible and credible.

ProCaLung - Peer review in stage III, mediastinal node-positive, non-small-cell lung cancer: How to benchmark clinical practice of nodal target volume definition and delineation in Belgium☆

BACKGROUND AND PURPOSE

The Quality Assurance project for stage III non-small cell lung cancer radiotherapy ProCaLung performed a multicentric two-step exercise evaluating mediastinal nodal Target Volume Definition and Delineation (TVD) variability and the opportunity for standardization. The TVD variability before and after providing detailed guidelines and the value of qualitative contour reviewing before applying quantitative measures were investigated.

MATERIALS AND METHODS

The case of a patient with stage III NSCLC and involved mediastinal lymph nodes was used as a basis for this study. Twenty-two radiation oncologists from nineteen centers in Belgium and Luxembourg participated in at least one of two phases of the project (before and after introduction of ProCaLung contouring guidelines). The resulting thirty-three mediastinal nodal GTV and CTV contours were then evaluated using a qualitative-before-quantitative (QBQ) approach. First, a qualitative analysis was performed, evaluating adherence to most recent guidelines. From this, a list of observed deviations was created and these were used to evaluate contour conformity. The second analysis was quantitative, using overlap and surface distance measures to compare contours within qualitative groups and between phases. A 'most robust' reference volume for these analyses was created using the STAPLE-algorithm and an averaging method.

RESULTS

Five GTV and seven CTV qualitative groups were identified. Second step contours were more often in higher-conformity groups (p = 0.012 for GTV and p = 0.024 for CTV). Median Residual Mean Square Distances improved from 2.34 mm to 1.36 mm for GTV (p = 0.01) and from 4.53 mm to 1.58 mm for CTV (p < 0.0001). Median Dice coefficients increased from 0.81 to 0.84 for GTV (p = 0.07) and from 0.82 to 0.89 for CTV (p ≤ 0.001). Using HC-contours only to generate references translated in more robust quantitative evaluations.

CONCLUSION

Variability of mediastinal nodal TVD was reduced after providing the ProCaLung consensus guidelines. A qualitative review was essential for providing meaningful quantitative measures.

Competency level in radiotherapy across EU educational programmes: A cross-case study evaluating stakeholders' perceptions

INTRODUCTION

The education of Therapeutic Radiographers (TRs) is regulated in some countries but is not standardised across the EU, leading to differences in competencies between and within member states. This study aimed to explore stakeholders' perceptions regarding underdeveloped competencies of TRs practising on the linear accelerator, identified in a previous study by the same research team.

METHODS

Interviews with stakeholders from four countries (selected based on the characteristics of their degrees) were performed as part of this cross-case study. Stakeholders were asked to provide their perception regarding the least developed competencies identified in a previous study.

RESULTS

The 27 stakeholders confirmed that Pharmacology, Quality Assurance (QA), Management and Leadership, Research (from the previous study) were underdeveloped and identified Image Verification and Critical Thinking as additional underdeveloped competencies. Suggested causes included: lack of regulation of required competencies at the national level, lack of training dedicated to radiotherapy (RT) (taught within generic modules) and lack of time within the degree programme. The ideal academic level to develop these competencies and whether they are essential varied between country and stakeholder.

CONCLUSION

It is essential to regulate learning outcomes at the national level to ensure a high level of care is provided to all RT patients and, ideally, standardise it across Europe. Education institutions should review their curricula to ensure that sufficient time is dedicated to RT and that the essential competencies are developed. Due to time constraints within some programmes, some competencies must be developed after graduation.

IMPLICATIONS FOR PRACTICE

Lack of regulation of learning outcomes (at European level and national level in many countries) and lack of RT-specific training lead to underdeveloped competencies that may compromise patient care.

Optimal delineation of the clinical target volume for thymomas in the post-resection setting: A multi-center study

BACKGROUND

The definition of the clinical target volume (CTV) for post-operative radiotherapy (PORT) for thymoma is largely unexplored. The aim of this study was to analyze the difference in CTV delineation between radiation oncologists (RTO) and surgeons.

METHODS

This retrospective multi-center study enrolled 31 patients who underwent PORT for a thymoma from five hospitals. Three CTVs were delineated per patient: one CTV by the RTO, one CTV by the surgeon (blinded to the results of the RTO) and a joint CTV after collaboration. Volumes (cm³), Hausdorff distances (HD) and Dice similarity coefficients (DSC) were analyzed.

RESULTS

RTO delineated significantly bigger CTVs than surgeons (mean: 93.9 ± 63.1, versus 57.9 ± 61.3 cm³, p = 0.003). Agreement was poor between RO and surgeons, with a low mean DSC (0.34 ± 0.21) and high mean HD of 4.5 (±2.2) cm. Collaborative delineation resulted in significantly smaller volumes compared to RTO (mean 57.1 ± 58.6 cm³, p < 0.001). A mean volume of 18.9 (±38.1) cm³ was included in joint contours, but missed by RTO. Conversely, a mean volume of 55.7 (±39.9) cm³ was included in RTO's delineations, but not in the joint delineations.

CONCLUSIONS

To the best of our knowledge, this is the first study investigating CTV definition in thymoma. We demonstrated a significant variability between RTO and surgeons. Joint delineation prompted revisions in smaller CTV as well as favoring the surgeons' judgement, suggesting that surgeons provided relevant insight into other risk areas than RTO. We recommend a multidisciplinary approach to PORT for thymomas in clinical practice.

Inter-clinician delineation variation for a new highly-conformal flank target volume in children with renal tumors: A SIOP-Renal Tumor Study Group international multicenter exercise

BACKGROUND AND PURPOSE

Recently, the SIOP-RTSG developed a highly-conformal flank target volume definition for children with renal tumors. The aims of this study were to evaluate the inter-clinician delineation variation of this new target volume definition in an international multicenter setting and to explore the necessity of quality assurance.

MATERIALS AND METHODS

Six pediatric renal cancer cases were transferred to ten radiation oncologists from seven European countries ('participants'). These participants delineated the pre- and postoperative Gross Tumor Volume (GTVpre/post), and Clinical Target Volume (CTV) during two test phases (case 1-2 and 3-4), followed by guideline refinement and a quality assurance phase (case 5-6). Reference target volumes (TVref) were established by three experienced radiation oncologists. The Dice Similarity Coefficient between the reference and participants (DSCref/part) was calculated per case. Delineations of case 5-6 were graded by four independent reviewers as 'per protocol' (0-4 mm), 'minor deviation' (5-9 mm) or 'major deviation' (≥10 mm) from the delineation guideline using 18 standardized criteria. Also, a major deviation resulting in underestimation of the CTVref was regarded as an unacceptable variation.

RESULTS

A total of 57/60 delineation sets were completed. The median DSCref/part for the CTV was 0.55 without improvement after sequential cases (case 3-4 vs. case 5-6: p = 0.15). For case 5-6, a major deviation was found for 5/18, 12/17, 18/18 and 4/9 collected delineations of the GTVpre, GTVpost, CTV-T and CTV-N, respectively. An unacceptable variation from the CTVref was found for 7/9 participants for case 5 and 6/9 participants for case 6.

CONCLUSION

This international multicenter delineation exercise demonstrates that the new consensus for highly-conformal postoperative flank target volume delineation leads to geometrical variation among participants. Moreover, standardized review showed an unacceptable delineation variation in the majority of the participants. These findings strongly suggest the need for additional training and centralized pre-treatment review when this target volume delineation approach is implemented on a larger scale.

Challenges in the target volume definition of lung cancer radiotherapy

Radiotherapy, with or without systemic treatment has an important role in the management of lung cancer. In order to deliver the treatment accurately, the clinician must precisely outline the gross tumour volume (GTV), mostly on computed tomography (CT) images. However, due to the limited contrast between tumour and non-malignant changes in the lung tissue, it can be difficult to distinguish the tumour boundaries on CT images leading to large interobserver variation and differences in interpretation. Therefore the definition of the GTV has often been described as the weakest link in radiotherapy with its inaccuracy potentially leading to missing the tumour or unnecessarily irradiating normal tissue. In this article, we review the various techniques that can be used to reduce delineation uncertainties in lung cancer.

[Diffusion-weighted imaging-diagnostic supplement or alternative to contrast agents in early detection of malignancies?]

Medical research in the field of oncologic imaging diagnostics using magnetic resonance imaging increasingly includes diffusion-weighted imaging (DWI) sequences. The DWI sequences allow insights into different microstructural diffusion properties of water molecules in tissues depending on the sequence modification used and enable visual and quantitative analysis of the acquired imaging data. In DWI, the application of intravenous gadolinium-containing contrast agents is unnecessary and only the mobility of naturally occurring water molecules in tissues is quantified. These characteristics predispose DWI as a potential candidate for emerging as an independent diagnostic tool in selected cases and specific points in question. Current clinical diagnostic studies and the ongoing technical developments, including the increasing influence of artificial intelligence in radiology, support the growing importance of DWI. Especially with respect to selective approaches for early detection of malignancies, DWI could make an essential contribution as an eligible diagnostic tool; however, prior to discussing a broader clinical implementation, challenges regarding reliable data quality, standardization and quality assurance must be overcome.

An in-silico quality assurance study of contouring target volumes in thoracic tumors within a cooperative group setting

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We aimed at quantifying inter-observer Pancoast tumors delineation variability.

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Experts’ delineations were used to define ground truth.

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Other observers’ delineations were compared against ground truth.

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High degree of variability was noted for most target volumes except GTV_P.

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This unveils potentials for protocol modification for future IMRT studies.

Introduction

Target delineation variability is a significant technical impediment in multi-institutional trials which employ intensity modulated radiotherapy (IMRT), as there is a real potential for clinically meaningful variances that can impact the outcomes in clinical trials. The goal of this study is to determine the variability of target delineation among participants from different institutions as part of Southwest Oncology Group (SWOG) Radiotherapy Committee’s multi-institutional in-silico quality assurance study in patients with Pancoast tumors as a “dry run” for trial implementation.

Methods

CT simulation scans were acquired from four patients with Pancoast tumor. Two patients had simulation 4D-CT and FDG-FDG PET-CT while two patients had 3D-CT and FDG-FDG PET-CT. Seventeen SWOG-affiliated physicians independently delineated target volumes defined as gross primary and nodal tumor volumes (GTV_P & GTV_N), clinical target volume (CTV), and planning target volume (PTV).

Six board-certified thoracic radiation oncologists were designated as the ‘Experts’ for this study. Their delineations were used to create a simultaneous truth and performance level estimation (STAPLE) contours using ADMIRE software (Elekta AB, Sweden 2017). Individual participants’ contours were then compared with Experts’ STAPLE contours.

Results

When compared to the Experts’ STAPLE, GTV_P had the best agreement among all participants, while GTV_N showed the lowest agreement among all participants. There were no statistically significant differences in all studied parameters for all TVs for cases with 4D-CT versus cases with 3D-CT simulation scans.

Conclusions

High degree of inter-observer variation was noted for all target volume except for GTV_P, unveiling potentials for protocol modification for subsequent clinically meaningful improvement in target definition. Various similarity indices exist that can be used to guide multi-institutional radiotherapy delineation QA credentialing.