title: Changes in biologic markers of oxidative stress and plasma endotoxin levels in gynecologic cancer patients treated with pelvic radiotherapy: a pilot study.
abstract: OBJECTIVE
  We conducted a pilot study to evaluate the effects of pelvic radiotherapy on biologic markers of oxidative stress and plasma endotoxin levels, and to assess the relationship between the changes of such factors and radiotherapy-related complications.
  
  
  METHODS
  Twelve gynecologic cancer patients who were treated via pelvic radiotherapy with or without concurrent chemotherapy were enrolled in this study. Biologic markers of oxidative stress, such as glutathione (GSH) and oxidized glutathione (GSSG), as well as endotoxin levels, were measured weekly during treatment. Subjective symptoms were assessed using the Korean version of the EORTC QLQ-C30 at the baseline and on the 5th week of radiotherapy.
  
  
  RESULTS
  No changes were noted in the level of GSH in whole blood, but the GSH/GSSG ratio was reduced dramatically after the initiation of radiotherapy. The mean plasma endotoxin for all patients tended to increase and persisted during radiotherapy, and the number of patients who evidenced clinically significant endotoxin levels (defined as >0.005 EU/mL) also increased. Nausea/vomiting and diarrhea were significantly changed (p=0.019 and p<0.001, respectively). A significant relationship was noted to exist between the changes in the endotoxin level and nausea/vomiting (p=0.001). However, such symptoms did not correlate with the changes of oxidative stress markers.
  
  
  CONCLUSIONS
  Pelvic radiotherapy oxidized the GSH redox system and increased plasma endotoxin. Further investigations containing interventional and longitudinal studies will be required to assess the effects of the changes in oxidative stress markers and endotoxin on radiotherapy-related adverse events.
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Hak Jae
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Kim
authors.forename: Sung Whan
authors.initials: SW
authors.lastname: Ha
authors.forename: Hong-Gyun
authors.initials: HG
authors.lastname: Wu
authors.forename: Jin Hwa
authors.initials: JH
authors.lastname: Choi
authors.forename: Kyung-Mi
authors.initials: KM
authors.lastname: Lee
authors.forename: Seung Wan
authors.initials: SW
authors.lastname: Kang