External validation of a combined PET and MRI radiomics model for prediction of recurrence in cervical cancer patients treated with chemoradiotherapy
The aim of this study was to validate previously developed radiomics models relying on just two radiomics features from 18F-fluorodeoxyglucose positron emission tomography (PET) and magnetic resonance imaging (MRI) images for prediction of disease free survival (DFS) and locoregional control (LRC) in locally advanced cervical cancer (LACC).
Patients with LACC receiving chemoradiotherapy were enrolled in two French and one Canadian center. Pre-treatment imaging was performed for each patient. Multicentric harmonization of the two radiomics features was performed with the ComBat method. The models for DFS (using the feature from apparent diffusion coefficient (ADC) MRI) and LRC (adding one PET feature to the DFS model) were tuned using one of the French cohorts (n = 112) and applied to the other French (n = 50) and the Canadian (n = 28) external validation cohorts.
The DFS model reached an accuracy of 90% (95% CI [79–98%]) (sensitivity 92–93%, specificity 87–89%) in both the French and the Canadian cohorts. The LRC model reached an accuracy of 98% (95% CI [90–99%]) (sensitivity 86%, specificity 100%) in the French cohort and 96% (95% CI [80–99%]) (sensitivity 83%, specificity 100%) in the Canadian cohort. Accuracy was significantly lower without ComBat harmonization (82–85% and 71–86% for DFS and LRC, respectively). The best prediction using standard clinical variables was 56–60% only.
The previously developed PET/MRI radiomics predictive models were successfully validated in two independent external cohorts. A proposed flowchart for improved management of patients based on these models should now be confirmed in future larger prospective studies.
KeywordsRadiomics Prediction Chemoradiotherapy Cervical cancer External validation
Compliance with ethical standards
Conflict of interest
Authors François Lucia, Dimitris Visvikis, Martin Vallières, Marie-Charlotte Desseroit, Omar Miranda, Philippe Robin, Pietro Andrea Bonaffini, Joanne Alfieri, Ingrid Masson, Augustin Mervoyer, Caroline Reinhold, Olivier Pradier, Mathieu Hatt, Ulrike Schick declare that they have no conflict of interest.
No financial support was received for this work.
There are no potential conflicts of interest to disclose.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
Statement of translational relevance describing how the results might be applied to the future practice of cancer medicine
Our findings have a direct impact on patient management in clinical practice. A flowchart demonstrates how to exploit the two radiomics features necessary to guide and personalize treatment: the textural feature (EntropyGLCM) extracted from ADC maps derived from DWI-MRI acquisitions can identify patients with low risk of recurrence, for which it could be advised to avoid adjuvant treatment. Among the patients with a higher risk of recurrence, the second textural feature (GLNUGLRLM) extracted from the FDG PET can differentiate between patients with a risk of distant recurrence, for which a systemic adjuvant treatment or more intensive surveillance could be recommended, and those with locoregional relapse, for which a locoregional adjuvant treatment might be more beneficial. Both MRI and PET images are routinely acquired for LACC patients, and the radiomics features have standardized definition with the IBSI guidelines, therefore anyone could easily evaluate our models in their data.
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