Treatment response evaluation using the mean apparent diffusion coefficient in cervical cancer patients treated with definitive chemoradiotherapy.

Abstract

To investigate the pre- and posttreatment mean apparent diffusion coefficient (ADCmean ) of cervical cancer tumors treated with definitive chemoradiotherapy (CRT) and evaluate their correlation with recurrence and survival rates. Forty-four patients with cervical squamous cell carcinoma were retrospectively evaluated. All patients underwent multiparametric 1.5T magnetic resonance imaging (MRI) including T2 -weighted, fat-saturated T2 -weighted, dynamic contrast-enhanced (DCE), and diffusion-weighted imaging (DWI) sequences before and after treatment. Posttreatment MR images were acquired within a median of 3.2 months (range, 2.8-4.1 months) after completing CRT. We assessed the impact of primary tumor pre- and posttreatment ADC values on prognostic factors and treatment outcomes. The pre- and posttreatment ADCmean values were 0.882 ± 0.096 × 10(-3) mm(2) /sec and 1.159 ± 0.168 × 10(-3) mm(2) /sec, respectively, and the difference was statistically significant (P < 0.001). The median percent ADC change was 33.7% (range, 5.0-70.0%). Patients with disease recurrence had lower ADC values, both pretreatment (0.822 ± 0.096 × 10(-3) mm(2) /sec vs. 0.936 ± 0.058 × 10(-3) mm(2) /sec; P < 0.001) and posttreatment (1.060 ± 0.116 × 10(-3) mm(2) /sec vs. 1.248 ± 0.160 × 10(-3) mm(2) /sec; P < 0.001). The ADC change was lower in patients with recurrence (25.7% ± 13.0% vs. 42.8% ± 15.7; P < 0.001) than in patients without recurrence. In multivariate analysis, pelvic lymph node metastasis and pretreatment ADCmean were prognostic factors for overall survival (OS) and disease-free survival (DFS). ADC change between pre- and posttreatment DW-MRI was a prognostic factor for OS. DWI parameters, measured before and after treatment, may be useful prognostic biomarkers for tumor burden, recurrence, and survival in cervical cancer patients treated with CRT. The primary tumor pretreatment ADCmean is an independent prognostic factor for DFS and OS. J. MAGN. RESON. IMAGING 2016;44:1010-1019.