title: Tumor volume reduction rate is superior to RECIST for predicting the pathological response of rectal cancer treated with neoadjuvant chemoradiation: Results from a prospective study.
abstract: The aim of the present study was to compare the tumor volume reduction rate (TVRR), as determined by three-dimensional region-of-interest magnetic resonance volumetry, and Response Evaluation Criteria in Solid Tumors (RECIST) data for predicting the pathological tumor response (PTR) of locally advanced rectal cancer (LARC) following treatment with neoadjuvant chemoradiation (CRT). The current cohort consisted of 105 patients with LARC [clinical tumor stage (cT)3-4 or clinical lymph node stage (cN)+] from a prospective randomized trial who had undergone pre-operative CRT and radical proctectomy. Tumor volumes were measured prior to and following CRT to determine TVRR. Furthermore, receiver operating characteristic (ROC) curves of TVRR and RECIST were constructed to predict the PTR in terms of tumor regression grade (TRG) and downstaging. Values for the area under the ROC curve (AUC) were compared and TVRR cut-off levels were determined. RECIST was used to identify 5 (4.8%) cases of complete response, 44 (41.9%) of partial response, 55 (52.4%) of stable disease and 1 (0.9%) of progressive disease. The mean TVRR was 58.6±24.4%, and a good TRG (0-1) and downstaging occurred in 54 (51.4%) and 59 (56.2%) patients, respectively. In addition, TVRR and RECIST were significantly correlated with TRG and downstaging (P<0.01). The TVRR AUC was significantly larger than that of RECIST for TRG (P=0.020). For downstaging, TVRR also exhibited a larger AUC than RECIST, however, the difference was not significant (P=0.180). The sensitivity and specificity of TVRR in predicting a good TRG were 70.4 and 80.4%, respectively, therefore, the optimal TVRR cut-off value was determined to be 65%. TVRR appeared to be more accurate than RECIST in predicting PTR, particularly for TRG associated with survival. Thus, TVRR may be considered as a novel parameter for evaluating the efficacy of CRT for patients with LARC.
authors.affiliation: Department of Medical Oncology, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Department of Medical Oncology, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, National University of Singapore, Singapore 169856, Republic of Singapore.
authors.forename: Wenyun
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Jiaying
authors.initials: J
authors.lastname: Gong
authors.affiliation: Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Zhiyang
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Pathology, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Radiation Oncology, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Department of Medical Oncology, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Junsheng
authors.initials: J
authors.lastname: Peng
authors.affiliation: Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Donglin
authors.initials: D
authors.lastname: Ren
authors.affiliation: Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Ping
authors.initials: P
authors.lastname: Lan
authors.affiliation: Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, P.R. China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
keywords: Response Evaluation Criteria in Solid Tumors; downstaging; neoadjuvant chemoradiation; rectal cancer; tumor regression grade; tumor volume reduction rate