Effect of biopsy on the MRI radiomics classification of benign lesions and luminal A cancers

Radiomic features extracted from breast magnetic resonance (MR) images have demonstrated potential in diagnosis and prognosis of breast cancer. However, presentation of lesions on MRI may be affected by a biopsy event. We investigated, relative to biopsy condition, the difference in radiomic features and performance (the area under the receiver operating curve (AUC)) for the task of distinguishing between benign lesions and luminal A cancers. Dynamic contrast-enhanced MR images were collected retrospectively under IRB/HIPAA compliance. The 361-case dataset included 92 benign and 30 luminal A lesions imaged pre-biopsy and 40 benign and 199 luminal A lesions imaged post-biopsy. Thirty-four radiomic non-size features were extracted and their values compared for each group of lesions by biopsy condition using the Kolmogorov-Smirnov test to determine if the two groups were drawn from the same patient distribution. For each feature by biopsy condition, the median of the AUC and the confidence interval for the difference in AUC were determined (2000 bootstrap iterations). In all analyses, after correction for multiple comparisons, a difference was considered significant when the p-value was less than 0.0015 (0.05/34) or, equivalently, the 99.85% confidence interval for the difference excluded zero. If comparisons failed to meet p < 0.0015, features were considered potentially robust. While, as expected, the morphology feature of irregularity was significantly different (p = 0.0003) for benign lesions due to how biopsy events increased irregularity of benign lesions, most features were potentially robust between biopsy conditions. While features did well in distinguishing between luminal A and benign lesions, all failed to demonstrate significance differences in AUC between biopsy conditions.