title: Radiation-induced apoptosis of peripheral blood lymphocytes is correlated with histological regression of rectal cancer in response to preoperative chemoradiotherapy.
abstract: OBJECTIVE
  The response of rectal cancer to preoperative chemoradiotherapy (PRT) varies widely among patients, and predictors of the response remain to be elucidated. The purpose of this study is to investigate whether radiation-induced apoptosis (RIA) of peripheral blood lymphocytes (PBLs) reflects the underlying intrinsic radiosensitivity of rectal cancer.
  
  
  METHODS
  Forty-one patients with clinical T3-4, M0 low rectal cancers, treated with PRT and curative surgery, were retrospectively studied. PBLs were obtained from blood samples of the patients, irradiated at 0, 2, 8, and 16 Gy in vitro, and analyzed for RIA by flow cytometry using Annexin V (AV) and propidium iodide (PI). The correlation of the RIA of PBLs and histological regression of rectal cancer in response to PRT was examined.
  
  
  RESULTS
  Both the proportions of AV+/PI- PBLs (early apoptosis) and AV+/PI + PBLs (late apoptosis) were significantly higher in patients with high histological regression than in those with low histological regression. Age, sex, tumor size, and clinical T and N stages did not affect the RIA of PBLs.
  
  
  CONCLUSIONS
  This study showed that the RIA of PBLs is correlated with the histological regression of rectal cancer in response to PRT and suggested that the radiosensitivity of rectal cancer might be estimated by the RIA of PBLs.
authors.affiliation: Department of Surgery, Teikyo University, 2-11-1, Kaga, Itabashi-ku, Tokyo, Japan. sochan31@hotmail.com
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ishihara
authors.forename: Hisae
authors.initials: H
authors.lastname: Iinuma
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Fukushima
authors.forename: Takuya
authors.initials: T
authors.lastname: Akahane
authors.forename: Atsushi
authors.initials: A
authors.lastname: Horiuchi
authors.forename: Ryu
authors.initials: R
authors.lastname: Shimada
authors.forename: Hajime
authors.initials: H
authors.lastname: Shibuya
authors.forename: Tamuro
authors.initials: T
authors.lastname: Hayama
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamada
authors.forename: Keijiro
authors.initials: K
authors.lastname: Nozawa
authors.forename: Keiji
authors.initials: K
authors.lastname: Matsuda
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000368:Aged; D017209:Apoptosis; D059186:Chemoradiotherapy, Adjuvant; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000473:pathology* / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011300:Preoperative Care; D012004:Rectal Neoplasms / Q000097:blood* / Q000473:pathology / Q000628:therapy*; D012074:Remission Induction