title: Tumor Volume Reduction Rate Predicts Pathologic Tumor Response of Locally Advanced Rectal Cancer Treated with Neoadjuvant Chemotherapy alone: Results from a Prospective Trial.
abstract: OBJECTIVE
  To evaluate tumor volume reduction rate (TVRR) measured by three-dimensional region-of-interest (3D-ROI) magnetic resonance (MR) volumetry in predicting pathological tumor response of preoperative chemotherapy alone for locally advanced rectal cancer (LARC).
  
  
  METHODS
  LARC patients who received neoadjuvant chemotherapy only from a prospective and randomized trial were recruited. Tumor volumes were measured with 3D-ROI MR volumetry. TVRR was determined using the equation TVRR = (VPre-Therapy - VPost-Therapy) / VPre-Therapy ×100%. Correlation between TVRR and clinical or pathological characteristics and predictive value of TVRR for pathological tumor response in terms of Tumor Regression Grade (TRG), T downstage, N downstage and overall downstage were analyzed.
  
  
  RESULTS
  80 eligible cases of LARC were included in our study with TVRR of (51.7±25.1) %. TVRR was higher in well-differentiated tumors compared with poor-differentiated tumors (P=0.040). TVRR was found to be related with TRG (P<0.001), T downstage (P<0.001) and overall downstage (P<0.001). Risk of achieving TRG 2/3 decreased to 57.5% (P=0.002) and odds of achieving overall downstage increase to 179.3% (P<0.001) when TVRR increased by every 10%. A sensitivity of 0.704 and specificity of 0.804 were calculated when ROC curve was constructed to predict TRG using TVRR with a cutoff of 65%.
  
  
  CONCLUSIONS
  TVRR is correlated with TRG and overall downstage significantly in LARC patients treated with preoperative chemotherapy alone and shows great value in predicting favorable TRG and overall downstage with good sensitivity and specificity. It could be considered as a promising parameter candidate for efficacy evaluation.
authors.affiliation: 1. Department of Medical Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xiao
authors.affiliation: 2. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Zerong
authors.initials: Z
authors.lastname: Cai
authors.affiliation: 3. Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, National University of Singapore, 169856, Singapore.
authors.forename: Wenyun
authors.initials: W
authors.lastname: Li
authors.affiliation: 2. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Zuli
authors.initials: Z
authors.lastname: Yang
authors.affiliation: 4. Department of Radiology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Jiaying
authors.initials: J
authors.lastname: Gong
authors.affiliation: 5. Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: 1. Department of Medical Oncology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Deng
authors.affiliation: 2. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Wu
authors.affiliation: 2. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: 2. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Junsheng
authors.initials: J
authors.lastname: Peng
authors.affiliation: 2. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Donglin
authors.initials: D
authors.lastname: Ren
authors.affiliation: 2. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Ping
authors.initials: P
authors.lastname: Lan
authors.affiliation: 2. Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, P.R. China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
keywords: Chemotherapeutic Efficacy; Neoadjuvant Chemotherapy; Rectal Cancer; TVRR