title: 'Deepness of Response' Is Associated with Overall Survival in Standard Systemic Chemotherapy for Metastatic Colorectal Cancer.
abstract: BACKGROUND
  The identification of responders is an important issue in chemotherapy for metastatic colorectal cancer (mCRC). 'Deepness of response' (DpR), defined as the maximum rate of reduction from the initial tumor burden, was recently proposed as a novel hypothetical parameter associated with overall survival (OS) in first-line chemotherapy plus cetuximab for mCRC. We determined whether this concept was universally applicable to diverse standard chemotherapeutic regimens for mCRC.
  
  
  METHODS
  We reviewed mCRC patients who received the first-line systemic chemotherapy regimens FOLFOX, CapeOX or FOLFIRI (with biologics) at our department between June 2005 and March 2015. Data such as clinicopathological parameters, metastasized organs, chemotherapeutic regimens, the best response by RECIST v1.1, progression-free survival (PFS) and OS were retrospectively retrieved for patients who exhibited tumor shrinkage. DpR was calculated as the uni-dimensional maximum reduction rate of measurable tumors. We addressed the association between DpR and survival.
  
  
  RESULTS
  Of the 156 patients receiving first-line chemotherapy regimens, tumor shrinkage was observed in 63 (41 of whom were men; median age 62 years). Complete remission was achieved in 6 patients, partial remission in 42 and stable disease in 15. The median DpR was 44.2% and was employed as the cutoff, in line with previous reports. DpR ≥45% (31 patients) was correlated with longer PFS (median 16.4 vs. 8.1 months for DpR <45%, p = 0.006) and OS (median 58.6 vs. 30.9 months for DpR <45%, p = 0.041). There was basically no difference in the subsequent chemotherapy between the DpR ≥45% and DpR <45% groups.
  
  
  CONCLUSIONS
  DpR correlated with OS in various first-line systemic upfront chemotherapy regimens for mCRC.
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nozawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishikawa
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Junichiro
authors.initials: J
authors.lastname: Tanaka
authors.forename: Tomomichi
authors.initials: T
authors.lastname: Kiyomatsu
authors.forename: Kazushige
authors.initials: K
authors.lastname: Kawai
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hata
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Kazama
authors.forename: Hironori
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ishihara
authors.forename: Eiji
authors.initials: E
authors.lastname: Sunami
authors.forename: Joji
authors.initials: J
authors.lastname: Kitayama
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D000068258:Bevacizumab / Q000008:administration & dosage; D000068818:Cetuximab / Q000008:administration & dosage; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012074:Remission Induction / Q000379:methods; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D016896:Treatment Outcome
chemical_list: D000068258:Bevacizumab; D000068818:Cetuximab