Apparent diffusion coefficient for the prediction of tumor response to neoadjuvant chemo-radiotherapy in locally advanced rectal cancer

Abstract

Background Patients with locally advanced rectal cancer generally have different response rates to preoperative neoadjuvant chemo-radiotherapy. This study investigated the value of the apparent diffusion coefficient (ADC) as a predictor to forecast the response to neoadjuvant chemo-radiotherapy in patients with locally advanced rectal cancer. Methods Ninety-one locally advanced rectal cancer patients who underwent neoadjuvant chemo-radiotherapy between 2015 and 2018 were enrolled. Diffusion-weighted magnetic resonance imaging was performed before treatment and within 4 weeks after the completion of neoadjuvant chemo-radiotherapy. Mean ADC values of regions of interest were evaluated by two radiologists. The tumor response was evaluated according to RESCIST 1.1. The cut-off value for the mean ADC and increasing percentage (ΔADC%) after neoadjuvant chemo-radiotherapy was calculated using the receiver operating characteristic curve. The response rate of pre-ADC and ΔADC% above/below the cut-off values was determined using the chi-square test, respectively. Primary tumor progression-free survival (PFS) was analyzed using the Kaplan–Meier method, based on the pre-ADC and ΔADC% cut-off values. Results The cut-off value of mean pre-ADC and ΔADC% was 0.94 × 10–3 mm2/s (80.36% sensitivity, 74.29% specificity) and 26.0% (73.21% sensitivity, 77.14% specificity), respectively. Lower mean pre-ADC values were related to a better response rate (83.3% vs 29.7%, P < 0.001) and PFS (26.12 vs 17.70 months, P = 0.004). ΔADC% above the cut-off value was also related to a better response rate (83.7% vs 35.7%, P < 0.001) and PFS (26.93 vs 15.65 months, P = 0.034). Conclusions The mean ADC pre-treatment value and ΔADC% were potential predictors for the tumor response in locally advanced rectal cancer patients treated with neoadjuvant chemo-radiotherapy.

Changes in Apparent Diffusion Coefficient (ADC) in Serial Weekly MRI during Radiotherapy in Patients with Head and Neck Cancer: Results from the PREDICT-HN Study

“…Apparent diffusion coefficient (ADC) is a measure of the diffusion of water molecules from DWI images. There is evidence that ADC is predictive and prognostic in other malignancies [ 7 , 8 , 9 , 10 ], and in HNSCC in terms of locoregional failure [ 11 , 12 ]. We have presented a systematic and comprehensive prospective assessment of the kinetics of ADC values in primary and nodal tumours during radiotherapy in patients with HNSCC.…”

Combination of intravoxel incoherent motion histogram parameters and clinical characteristics for predicting response to neoadjuvant chemoradiation in Rectal Cancer

“…Compared with traditional MRI, fMRI could provide more details in the tumor microenvironment, including cell density, tissue component, and microcirculation perfusion, which were associated with tumor biological characteristics and response to treatment [32,33]. A recent study revealed that the ADC values before treatment could predict patients with good response, and the AUCs, sensitivity, and speci city were 0.801, 80.36%, and 74.29%, respectively [10]. However, our result showed that no difference was found in pretreatment ADC values between the pCR group and the non-pCR group, which was in line with Yuan, Y. et al's study [34].…”

“…ADC values obtained at DWI have been con rmed to be related to tumor cellularity, with lower ADC values associated with increased tumor cellularity [9]. However, these studies on the use of ADC values for treatment response evaluation are inconsistent [10][11][12][13][14]. These con icting results may partly be because the ADC values calculated from DWI are based on a mono-exponential decay model, which hypothesizes the free motion of water molecules following a Gaussian distribution [15].…”

Current progress and future perspectives of neoadjuvant anti-PD-1/PD-L1 therapy for colorectal cancer

“…MRI can accurately display the anatomy of rectum and adjacent organs, further providing relatively accurate information on the tumor stage. However, since the measurement of the tumor site after neoadjuvant therapy is often interfered by necrosis and other factors, traditional MRI methods cannot accurately monitor the tumor response (79). Due to immune cell infiltration and other reasons, one of the characteristics of immune neoadjuvant therapy is that the imaging and pathological evaluation results may differ greatly.…”