The quality and clinical translation of radiomics studies based on MRI for predicting Ki-67 levels in patients with breast cancer

Objective: To evaluate the methodological quality of radiomics literature predicting Ki- 67 levels based on MRI in patients with breast cancer (BC) and to propose suggestions for clinical translation. Methods: In this review, we searched PubMed, Embase, and Web of Science for studies published on radiomics in patients with BC. We evaluated the methodological quality of the studies using the Radiomics Quality Score (RQS). The Cochrane Collaboration's software (RevMan 5.4), Meta- DiSc (v. 1.4) and IBM SPSS (v. 26.0) were used for all statistical analyses. Results: Eighteen studies met our inclusion criteria, and the average RQS was 10.17 (standard deviation [SD]: 3.54). None of these studies incorporated any of the following items: a phantom study on all scanners, cut-off analyses, prospective study, cost-effectiveness anal-ysis, or open science and data. In the meta-analysis, it showed apparent diffusion coefficient (ADC) played a better role to predict Ki- 67 level than dynamic contrast -enhanced (DCE) MRI in the radiomics, with the pooled area under the curve (AUC) of 0.969. Conclusion: Ki- 67 index is a common tumor biomarker with high clinical value. Radiomics is an ever-growing quantitative data-mining method helping predict tumor biomarkers from medical images. However, the quality of the reviewed studies evaluated by the RQS was not so satisfactory and there are ample opportunities for improvement. Open science and data, external valida-tion, phantom study, publicly open radiomics database and standardization in the radiomics practice are what researchers should pay more attention to in the future. Advances in knowledge: The RQS tool considered the radiomics used to predict the Ki- 67 level was of poor quality. ADC performed better than DCE in radiomic prediction. We propose some measures to facilitate the clinical translation of radiomics.