Diffusion-weighted magnetic resonance imaging for prediction of tumor response to neoadjuvant chemoradiotherapy using irinotecan plus S-1 for rectal cancer

Abstract

Abstract. The purpose of this study was to investigate the clinical value of diffusion-weighted (DW) magnetic resonance imaging (MRI) as a predictor of tumor response in patients receiving neoadjuvant chemoradiotherapy (NA-CRT) for rectal cancer (RC) through measurement of the apparent diffusion coefficient (ADC) value in each tumor. Neoadjuvant radiotherapy with a total dose of 45 Gy in 25 fractions was performed in all 16 patients with RC, combined with irinotecan and S-1. MRI was performed before and after NA-CRT. Multiple factors were assessed to predict the pathological response to NA-CRT. The pathological response rate was determined in 9 patients (56.3%). Statistical analyses indicated that the ADC value prior to NA-CRT was significantly lower in patients with a better response to NA-CRT (P= 0.023). A cut-off value of 0.750x10 -3 mm 2 /sec obtained by a receiver operating characteristic curve analysis indicated a sensitivity of 77.8% and specificity of 85.7% for pathological responders to NA-CRT. In addition, the patients with lower ADC values exhibited a greater pathological response to NA-CRT (P= 0.041). In conclusion, the ADC value of MRI of RC patients treated with NA-CRT followed by surgery may provide valuable information to predict the response to NA-CRT.

Assessing response to neo-adjuvant therapy in locally advanced rectal cancer using Intra-voxel Incoherent Motion modelling by DWI data and Standardized Index of Shape from DCE-MRI

“…There are several studies that with a single modality examine the capability of evaluating therapy response. 11 – 16 , 39 , 40 We demonstrated the ability of SIS to detect complete and significant response after pCRT in LARC 15 and the strength of SIS compared with fluorodeoxyglucose positron-emission tomography ( 18 F-FDG-PET) examination. 41 Some studies demonstrated the role of DWI in LARC for assessing therapy response 39 , 40 and several studies evaluated the use of the IVIM model for extracting DWI data by both perfusion and diffusion parameters in different types of tumours.…”

“… 11 – 16 , 39 , 40 We demonstrated the ability of SIS to detect complete and significant response after pCRT in LARC 15 and the strength of SIS compared with fluorodeoxyglucose positron-emission tomography ( 18 F-FDG-PET) examination. 41 Some studies demonstrated the role of DWI in LARC for assessing therapy response 39 , 40 and several studies evaluated the use of the IVIM model for extracting DWI data by both perfusion and diffusion parameters in different types of tumours. 32 , 33 , 42 In our previous study, 10 we compared SIS with diffusion parameters and their combination after short-course radiotherapy in LARC, demonstrating that no accuracy increase was obtained combining linearly each possible perfusion and diffusion parameter couple extracted by DCE-MRI and DWI or combining all functional MR-derived parameters with respect to SIS alone.…”