Prediction of treatment response in patients with locally advanced cervical cancer using midtreatment PET/MRI during concurrent chemoradiotherapy
Abstrakt
PURPOSE: We aimed to find metabolic, functional or morphological characteristics of the tumor predicting failure to achieve complete metabolic remission (CMR) by the midtreatment PET/MRI (positron emission tomography/magnetic resonance imaging) in cervical cancer patients. METHODS: We evaluated 66 patients treated between August 2015 and November 2019 who underwent pretreatment staging, subsequent midtreatment evaluation, and definitive restaging 3 months after completing the whole treatment, all using PET/MRI.
The pretreatment parameters (pre-SUVmax, pre-SUVmean, pre-MTV, pre-MTV-S, pre-TLG, pre-TLG-S [SUV: standard uptake value, MTV: metabolic tumor volume, TLG: total lesion glycolysis]), and the midtreatment parameters at week 5 during chemoradiotherapy (mid-SUVmax, mid-SUVmean, mid-MTV, mid-MTV-S, mid-TLG and mid-TLG-S) were recorded. The value of ADC (apparent diffusion coefficient) was also measured.
Furthermore, we recorded absolute and relative changes in all parameters-INCREMENT and INCREMENT %. We divided the whole group of patients into "responders" (CMR) and "non-responders" (non-CMR), and compared them on the basis of the parameters from pre-PET/MRI and mid-PET/MRI.
RESULTS: A statistically significant difference in the evaluated parameters between responders and non-responders was found for the following parameters: mid-MTV, mid-TLG, mid-TLG-S, mid-MTV-S, mid-tumor size, and INCREMENT %SUVmax. According to the ROC (receiver operating characteristic) analysis, mid-MTV-S showed the best albeit moderate discrimination ability for the prediction of non-CMR.
Significant mutual correlations of all variables, in particular between mid-MTV-S and mid-TLG-S and between mid-MTV and mid-TLG, were found (all p < 0.05). CONCLUSION: Our study confirmed that when using the midtreatment PET/MRI we are able to identify metabolic parameters having the discrimination ability for the prediction of non-CMR.
In particular mid-MTV-S, mid-MTV, mid-tumor size, mid-TLG-S, mid-TLG and INCREMENT %SUVmax.