External validation of an MR-based radiomic model predictive of locoregional control in oropharyngeal cancer

P. Bos, Rob Martens, P. de Graaf, B. Jasperse, Joost J.M. van Griethysen, Ronald Boellaard, R.C. Leemans, R.G.H. Beets-Tan, M. van der Wiel, M.W.M. van den Brekel, J.A. Castelijns, Joost J. M. van Griethuysen, C. René Leemans

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Objectives: To externally validate a pre-treatment MR-based radiomics model predictive of locoregional control in oropharyngeal squamous cell carcinoma (OPSCC) and to assess the impact of differences between datasets on the predictive performance.

Methods: Radiomic features, as defined in our previously published radiomics model, were extracted from the primary tumor volumes of 157 OPSCC patients in a different institute. The developed radiomics model was validated using this cohort. Additionally, parameters influencing performance, such as patient subgroups, MRI acquisition, and post-processing steps on prediction performance will be investigated. For this analysis, matched subgroups (based on human papillomavirus (HPV) status of the tumor, T-stage, and tumor subsite) and a subgroup with only patients with 4-mm slice thickness were studied. Also the influence of harmonization techniques (ComBat harmonization, quantile normalization) and the impact of feature stability across observers and centers were studied. Model performances were assessed by area under the curve (AUC), sensitivity, and specificity.

Results: Performance of the published model (AUC/sensitivity/specificity: 0.74/0.75/0.60) drops when applied on the validation cohort (AUC/sensitivity/specificity: 0.64/0.68/0.60). The performance of the full validation cohort improves slightly when the model is validated using a patient group with comparable HPV status of the tumor (AUC/sensitivity/specificity: 0.68/0.74/0.60), using patients acquired with a slice thickness of 4 mm (AUC/sensitivity/specificity: 0.67/0.73/0.57), or when quantile harmonization was performed (AUC/sensitivity/specificity: 0.66/0.69/0.60).

Conclusion: The previously published model shows its generalizability and can be applied on data acquired from different vendors and protocols. Harmonization techniques and subgroup definition influence performance of predictive radiomics models.

Key points: • Radiomics, a noninvasive quantitative image analysis technique, can support the radiologist by enhancing diagnostic accuracy and/or treatment decision-making. • A previously published model shows its generalizability and could be applied on data acquired from different vendors and protocols.

Keywords: Machine learning; Magnetic resonance imaging; Oropharyngeal neoplasms; Prognosis; Treatment outcome.
Original languageEnglish
Pages (from-to)2850–2860
Number of pages11
JournalEuropean Journal of Radiology
Volume33
Issue number4
Early online date3 Dec 2022
DOIs
Publication statusPublished - Apr 2023

Keywords

  • Machine learning
  • Machine learning; Magnetic resonance imaging; Oropharyngeal neoplasms; Prognosis; Treatment outcome
  • Magnetic resonance imaging
  • Oropharyngeal neoplasms
  • Prognosis
  • Treatment outcome

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