title: Circulating lymphocyte is an important determinant of the effectiveness of preoperative radiotherapy in advanced rectal cancer.
abstract: BACKGROUND
  Although preoperative radiotherapy (RT) is widely used as the initial treatment for locally advanced rectal cancer (RC) in the neoadjuvant setting, factors determining clinical response have not been adequately defined. In order to find other factors possibly related with radiosensitivity, we evaluated the relationships between circulating blood cell counts and RT effects.
  
  
  METHODS
  In 179 cases with advanced RC, we retrospectively examined hemoglobin (Hb) levels and counts of white blood cells (WBC), platelets and WBC subsets before and after RT and investigated their associations with the complete response (CR) rate together with other clinicopathological factors.
  
  
  RESULTS
  The ratio of lymphocytes in WBC taken before RT was significantly greater in 15 CR cases as compared with those in non-CR cases. Patients with high lymphocyte percentages (25.7%) showed better outcome than the counterparts. Conversely, the ratio of neutrophiles was reduced in CR cases. The lymphocyte ratio showed an independent association with CR with multivariate analysis, and tended to be maintained at relatively high levels in CR cases.
  
  
  CONCLUSIONS
  In RC patients, peripheral blood lymphocytes have a significant impact on the CR rate in response to RT. Lymphocyte-mediated immune reactions are supposed to have positive roles on clinical response in radiotherapy for RC.
authors.affiliation: Department of Surgery, Division of Surgical Oncology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. kitayama-1SU@h.u-tokyo.ac.jp
authors.forename: Joji
authors.initials: J
authors.lastname: Kitayama
authors.forename: Koji
authors.initials: K
authors.lastname: Yasuda
authors.forename: Kazushige
authors.initials: K
authors.lastname: Kawai
authors.forename: Eiji
authors.initials: E
authors.lastname: Sunami
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Nagawa
mesh_terms: D018572:Disease-Free Survival; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007958:Leukocyte Count; D016131:Lymphocyte Subsets; D008214:Lymphocytes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009504:Neutrophils / Q000473:pathology; D010976:Platelet Count; D011836:Radiation Tolerance; D012004:Rectal Neoplasms / Q000097:blood* / Q000532:radiotherapy* / Q000601:surgery; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D006454:Hemoglobins