Early treatment response of patients undergoing concurrent chemoradiotherapy for cervical cancer: An evaluation of integrated multi-parameter PET-IVIM MR.

PURPOSE

To evaluate the value of integrated multi-parameter positron emission tomography-intravoxel incoherent motion magnetic resonance (PET-IVIM MR) imaging in the assessment of treatment response in patients with cervical cancer treated with concurrent chemoradiotherapy (CCRT).

MATERIALS AND METHODS

A total of 41 patients underwent PET-MR scans before, during (at the end of the third week) and after CCRT were included in this study. The PET-MR imaging parameters were measured on the tumor and the percentage change between the two time points were calculated before and during the treatment. These parameters were used to evaluate treatment response. A combination prediction model was constructed using multivariate logistic regression. European Organization for Research and Treatment of Cancer (EORTC)criteria, measured by the post-therapy(PostTx) PET/MR were used to classify treatment responses: patients were classified into the complete metabolic responder (CMR) group or the non-complete metabolic responders (N-CMR) group. The correlations between PET and IVIM parameters and percentage changes during CCRT were investigated using the Spearman rank correlation.

RESULTS

In all, 13 of 41 (31.7%) patients were defined as N-CMR group. According to constructing multivariate logistic regression, the combination of pre-therapy(Pre-Tx) total metabolic tumor volume(MTV), the percentage changes of the maximum standardized uptake value (ΔSUV) and the mean diffusion-related coefficient (ΔD) during CCRT had the strongest predictive potentiality(AUC 0.912, P < 0.05).In addition,during CCRT the percentage changes in minimum diffusion-related coefficient(ΔD) was correlated with ΔSUV(Spearman correlation coefficient, r＝0.338, P < 0.05).

CONCLUSIONS

The combination of Pre-Tx MTV,ΔSUV and ΔD had the strongest predictive value in evaluating treatment response for patients with cervical cancer treated with CCRT. Other imaging parameters can be replaced by these 3 parameters because of their similarities and lower predictive values. In addition, ΔD and ΔSUV have a similar value for evaluating treatment response after CCRT in cervical cancer.