title: Diffusion-weighted magnetic resonance imaging for prediction of tumor response to neoadjuvant chemoradiotherapy using irinotecan plus S-1 for rectal cancer.
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 0.750×10-3mm2/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.
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Doi
authors.affiliation: Department of Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Naohito
authors.initials: N
authors.lastname: Beppu
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.affiliation: Department of Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Noda
authors.affiliation: Department of Surgery, Meiwa Hospital, Nishinomiya, Hyogo 663-8186, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yanagi
authors.affiliation: Department of Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Tomita
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Kamikonya
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Hirota
keywords: S-1; apparent diffusion coefficient; chemoradiotherapy; diffusion-weighted magnetic resonance imaging; irinotecan; magnetic resonance imaging; neoadjuvant chemoradiotherapy; preoperative radiotherapy; radiotherapy; rectal cancer