A study that analyzed tumor apparent diffusion coefficients (ADC) in patients with uterine cervical cancer (CC) found that tumor ADC predicted disease-specific survival (DSS).
Lura
In addition, there was an independent prognostic impact after adjusting for International Federation of Gynecology and Obstetrics (FIGO) 2018 staging, according to Njål Lura, MD, radiological consultant, PhD student, at Haukeland University Hospital and the University of Bergen, Norway. He presented the results of the study on Wednesday.
"Diffusion-weighted imaging (DWI) sequences of MRI guide local staging in primary uterine cervical cancer," Dr. Lura noted. "Diffusion of water in the tissue is quantified by ADC from DWI, and low ADC of the tumor has been linked to reduced survival for many cancers, including cervical cancer."
FIGO stage routinely guides prognostication and patient stratification to tailored therapeutic strategies, Dr. Lura asserted.
"However," he said, "some variability in survival within the FIGO 2018 substages does exist. Better pretherapeutic prognostic markers are needed to improve tailoring of targeted effective treatments in cervical cancer."
In this study, the researchers aimed to explore different approaches for tumor ADC measurements and compare their ability to predict survival and staging in cervical cancer analyses.
Measuring Tumor ADC Values
The researchers included 179 patients who were diagnosed with CC from 2009 to 2020. These patients all had visible primary tumor >2 cm and pretherapeutic MRI.
Diffusion weighted MR images of a patient with a large primary tumor in the uterine cervix (with a high b-value image at left, and apparent diffusion coefficient (ADC) map at right). The tumor is marked by blue arrows in both images (bright on the high b-value series and low intensity on the ADC map). Image courtesy of Njål Lura, MD.
Two radiologists read all MRIs independently, and recorded MRI-based local FIGO staging variables. They measured mean tumor ADC values in five manually selected regions of interest (ROIs) in tumor areas depicting the most restricted diffusion and calculated mean tumor ADC for the five measurements.
The mean ADC of the two raters was used. The researchers recorded ADC from ROIs in the myometrium (myometrium ADC) to calculate ratios for myometrium ADC/tumor-ADCmean.
ADC measurements were explored in relation to other imaging findings, FIGO stage, patient age, histologic grade (low/moderate vs. high) and DSS using Cox regression and the Akaike information criterion (AIC). Time-dependent receiver operating characteristic (tdROC) curves for predicting 5-year DSS were plotted.
Results and Implications for Patient Care
Tumor ADCmean predicted DSS (hazard ratio: 0.96; p<0.001) and was lower in patients who had tumor diameter >4 cm (p=0.003), vaginal growth (p=0.02), parametrial invasion (p=0.02), high histologic grade (p<0.001) and higher FIGO stage (p=0.04), according to Dr. Lura.
The researchers also found that myometrium ADC/ tumor-ADCmean significantly predicted DSS in the both the univariable (hazard ratio (HR): 4.64, p<0.001) and multivariable (HR: 2.84, p=0.001) model, including tumor diameter (HR=1.23, p<0.001), vaginal growth (HR=2.56, p=0.004) and high-grade histology (HR=2.35, p=0.01).
According to Dr. Lura, the multivariable model including FIGO stage yielded better prediction of 5-year DSS than the same model without FIGO stage or FIGO stage alone.
"Our study shows that low tumor ADC value is associated with poor DSS," Dr. Lura said. "We found it highly interesting that tumor ADC was a strong predictor of DSS, independent of FIGO stage and other well-known high-risk factors. This may open an avenue for better prediction of the high-risk subgroups that may profit from more tailored treatment regimens."
Access the presentation, "Tumor ADC Value Predicts Outcome and Yields Refined Prognostication in Patients with Uterine Cervical Cancer," (W7-SSOB03-4) on demand at Meeting.RSNA.org.
