Performance of diffusion-weighted magnetic resonance imaging at 3.0T for early assessment of tumor response in locally advanced rectal cancer treated with preoperative chemoradiation therapy

• DOI: 10.1007/s00261-018-1457-8
• Publication Date: 2018-01-13T02:34:43Z
• Authors: Andrea Delli Pizzi; Roberta Cianci; Domenico Genovesi; Gianluigi Esposito; Mauro Timpani; Alessandra Tavoletta; Pierluigi Pulsone; Raffaella Basilico; Daniela Gabrielli; Consuelo Rosa; Luciana Caravatta; Monica Di Tommaso; Massimo Caulo; Antonella Filippone
• Keywords: Adult; Male; Rectal Neoplasms; Chemoradiation treatment response; Complete responders; Diffusion-weighted imaging; Locally advanced rectal cancer; Magnetic resonance; Radiological and Ultrasound Technology; Radiology, Nuclear Medicine and Imaging; Gastroenterology; Urology; Chemoradiotherapy; Adenocarcinoma; Middle Aged; Sensitivity and Specificity; Neoadjuvant Therapy; 3. Good health; 03 medical and health sciences; Diffusion Magnetic Resonance Imaging; 0302 clinical medicine; Preoperative Care; Humans; Female; Prospective Studies; Neoplasm Grading; Aged

The purpose of the article is to determine whether changes in apparent diffusion coefficient (ADC) values of locally advanced rectal cancer (LARC) obtained 2 weeks after the beginning of chemoradiation therapy (CRT) allow to predict treatment response and whether correlate with tumor histopathologic response.Forty-three patients receiving CRT for LARC and 3.0T magnetic resonance imaging with diffusion-weighted sequences before treatment, 2 weeks during, and 8 weeks post the completion of CRT were included. ADC values were calculated at each time point and percentage of ADC changes at 2 weeks (ΔADC during) and 8 weeks (ΔADC post) were assessed. Data were correlated to surgical results and histopathologic tumor regression grade (TRG), according to Mandard's classification. ADC values and ΔADCs of complete responders (CR; TRG1) and non-complete responders (non-CR; TRG 2-5) were compared. Receiver-operating characteristic curve (ROC) analysis was used to assess diagnostic accuracy of ΔADC for differentiating CR from non-CR. The correlation with TRG was investigated using Spearman's rank test.ΔADC during and ΔADC post were significantly higher in CR (33.9% and 57%, respectively) compared to non-CR (13.5% and 2.2%, respectively) group (p = 0.006 and p < 0.001, respectively). ROC analysis revealed the following diagnostic performances: ΔADC during: AUC 0.78 (0.08), p = 0.004, cut-off 20.6% (sensitivity 75% and specificity 76.5%); ΔADC post: AUC 0.94 (0.04), p ≤ 0.001, cut-off 22% (sensitivity 95% and specificity 82.4%). Significant moderate and good negative correlation was found between ΔADC during and ΔADC post and TRG (r = - 0.418, p = 0.007; r = - 694, p ≤ 0.001, respectively).ΔADC at 2 weeks after the beginning of CRT is a reliable tool to early assess treatment response.