Correlation of Minimum Apparent Diffusion Coefficient and Maximum Standardized Uptake Value of the Primary Tumor with...

To explore the correlation of the primary tumor's maximum standardized uptake value (SUV_max) and minimum apparent diffusion coefficient (ADC_min) with clinicopathologic features, and to determine their predictive power in endometrial cancer (EC).

A total of 45 patients who had undergone staging surgery after a preoperative evaluation with ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) were included in a prospective case-series study with planned data collection. Multiple linear regression analysis was used to determine the correlations between the study variables.

The mean ADC_min and SUV_max values were determined as 0.72±0.22 and 16.54±8.73, respectively. A univariate analysis identified age, myometrial invasion (MI) and lymphovascular space involvement (LVSI) as the potential factors associated with ADC_min while it identified age, stage, tumor size, MI, LVSI and number of metastatic lymph nodes as the potential variables correlated to SUV_max. In multivariate analysis, on the other hand, MI was the only significant variable that correlated with ADC_min (p=0.007) and SUV_max (p=0.024). Deep MI was best predicted by an ADC_min cutoff value of ≤0.77 [93.7% sensitivity, 48.2% specificity, and 93.0% negative predictive value (NPV)] and SUV_max cutoff value of >20.5 (62.5% sensitivity, 86.2% specificity, and 81.0% NPV); however, the two diagnostic tests were not significantly different (p=0.266).

Among clinicopathologic features, only MI was independently correlated with SUV_max and ADC_min. However, the routine use of ¹⁸F-FDG PET/CT or DW-MRI cannot be recommended at the moment due to less than ideal predictive performances of both parameters.