Utility of diffusion-weighted imaging in association with pathologic upgrading in biopsy-proven grade I endometrial cancer: Upgrading Grade I Endometrial Cancer

BACKGROUND: Prediction of pathologic upgrading is clinically meaningful to identify the optimal candidate of fertility-preserving hormonal treatment in the young patients with biopsy-proven grade I endometrial cancer. PURPOSE: To investigate the utility of diffusion-weighted imaging (DWI) in association with pathologic upgrading in endometrial cancer. STUDY TYPE: Retrospective. SUBJECTS: Preoperative MRI datasets of 221 patients with grade I endometrial cancer on endometrial biopsy (n = 146), dilatation and curettage (n = 66), or either (n = 9). FIELD STRENGTH/SEQUENCE: 3.0T, including T2 -weighted imaging, DWI with a b-value of 1000 s/mm(2) , and dynamic contrast enhanced imaging. ASSESSMENT: The tumor size was determined as the longest diameter of the lesion. The minimum apparent diffusion coefficient (ADCmin ) was calculated using histogram analysis of the entire tumor. STATISTICAL TESTS: Mann-Whitney U-test, Pearson's chi-square test, Fisher's exact test, intraclass correlation coefficient (ICC) analysis, receiver operating characteristic (ROC) curve analysis, univariate and multivariate logistic regression analysis. RESULTS: Pathologic upgrading was identified in 42 patients (19.0%). Patients with pathologic upgrading had larger tumors and showed lower ADCmin values than those without pathologic upgrading (both P 3 cm (OR, 3.24; P = 0.009) were independently associated with pathologic upgrading. Upgrading occurred in 23 of 31 patients (74.2%) with ADCmin 3 cm, and in 7 of 114 patients (6.1%) with ADCmin >0.600 x 10(-3) mm(2) /s and tumor size