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☆. (February 2022)

• Record Type: Journal Article
• Authors: Charlier, Florian; Descamps, Thomas; Lievens, Yolande; Geets, Xavier; Remouchamps, Vincent; Lambrecht, Maarten; Moretti, Luigi
• Is Part Of: Radiotherapy and oncology. Volume 167(2022)
• Page Start: 57
• Page End: 64
• Publication Date: 2022-02
• Subjects: Lung neoplasms -- Radiotherapy -- Quality assurance -- Health care -- Peer review -- Lymph nodes -- Lymphatic irradiation -- Mediastinum -- Observer variation -- Practice guideline -- Qualitative research; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2021.11.034
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: Nodal definition and delineation for lung cancer is variable in clinical practice. Knowledge of anatomy and strict guidelines are crucial for high contouring quality. A qualitative review is essential to understanding interobserver variability. Quantitative evaluations are more robust if performed after a qualitative review. Standardization and peer review of clinical practice at country level is feasible. Abstract: 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.