Utility of diffusion‐weighted imaging in association with pathologic upgrading in biopsy‐proven 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/mm², and dynamic contrast enhanced imaging.

Assessment

The tumor size was determined as the longest diameter of the lesion. The minimum apparent diffusion coefficient (ADC_min) 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 ADC_min values than those without pathologic upgrading (both P < 0.001). The area under the ROC curve of ADC_min and tumor size was 0.812 and 0.758, respectively. On multivariate analysis, tumor ADC_min ≤0.600 × 10^‐3 mm²/s (odds ratio [OR], 11.8; P < 0.001) and tumor size on MRI >3 cm (OR, 3.24; P = 0.009) were independently associated with pathologic upgrading. Upgrading occurred in 23 of 31 patients (74.2%) with ADC_min ≤0.600 × 10^‐3 mm²/s and tumor size >3 cm, and in 7 of 114 patients (6.1%) with ADC_min >0.600 × 10^‐3 mm²/s and tumor size ≤3 cm.

Data Conclusion

Tumor ADC and tumor size on MRI may be useful parameters in association with pathologic upgrading in biopsy‐proven grade I endometrial cancer.

Level of Evidence: 4

Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:117–123.