title: Tumor compactness improves the preoperative volumetry-based prediction of the pathological complete response of rectal cancer after preoperative concurrent chemoradiotherapy.
abstract: In addition to clinical factors (tumor and node stage) and treatment factors (equivalent radiotherapy dose and chemotherapy regimen), we assessed whether different performances of various tumor volume measurements help predict the pathological complete response (pCR) of locally advanced rectal cancer (LARC) after preoperative concurrent chemoradiotherapy (CCRT). A total of 122 patients with LARC treated with a long course of CCRT, between December 2009 and March 2015, were enrolled in this bi-institutional study. Tumor delineation was based on standard T2-weighted magnetic resonance imaging or contrast-enhanced computed tomography before CCRT. Tumor compactness was defined as the ratio of the volume and the surface area. The tumor compactness-corrected TV (TCTV) was defined as the ratio of the real TV (RTV) and tumor compactness. Twenty-three (18.9%) patients had a pCR. Areas under the curve of the receiver operating characteristic for pCR prediction calculated using the RTV, cylindrical approximated TV (CATV), and TCTV were 0.724, 0.747, and 0.780, respectively. The prediction performance of TCTV was significantly more efficient than that of both RTV (P = 0.0057) and CATV (P = 0.0329). Multivariate logistic regression analysis revealed tumor compactness (P = 0.001), RTV (P = 0.042), and preoperative clinical nodal status (P = 0.044) as significant predictors of a pCR. In addition, poor tumor compactness was closely associated with lymphovascular space invasion (P = 0.008) and pathological nodal status (P = 0.003). For patients with LARC receiving preoperative CCRT, tumor compactness is a useful radiomic parameter for improving the volumetric based prediction model.
authors.affiliation: Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital Yun-Lin Branch, Yunlin, Taiwan.
authors.forename: Che-Yu
authors.initials: CY
authors.lastname: Hsu
authors.affiliation: Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University Cancer Center, Taipei, Taiwan.|National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Wang
authors.affiliation: Division of Radiation Oncology, Department of Oncology, Taiwan Medical University Hospital, Taipei, Taiwan.
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Kuo
authors.affiliation: Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University Cancer Center, Taipei, Taiwan.|National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University Cancer Center, Taipei, Taiwan.|National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Keng-Hsueh
authors.initials: KH
authors.lastname: Lan
authors.affiliation: National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei, Taiwan.|Cancer Research Center, National Taiwan University College of Medicine, Taipei, Taiwan.|Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Ann-Lii
authors.initials: AL
authors.lastname: Cheng
authors.affiliation: Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University Cancer Center, Taipei, Taiwan.|National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei, Taiwan.|Cancer Research Center, National Taiwan University College of Medicine, Taipei, Taiwan.|Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Sung-Hsin
authors.initials: SH
authors.lastname: Kuo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D059186:Chemoradiotherapy, Adjuvant; D013505:Digestive System Surgical Procedures; D005260:Female; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D015588:Observer Variation; D011237:Predictive Value of Tests; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D012307:Risk Factors; D013624:Taiwan; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult
keywords: chemoradiotherapy; pathologic complete remission; preoperative; rectal cancer; tumor compactness