title: Individual radiosensitivity measured with lymphocytes may predict the risk of acute reaction after radiotherapy.
abstract: OBJECTIVE
  We tested whether the chromosomal radiosensitivity of in vitro irradiated lymphocytes could be used to predict the risk of acute reactions after radiotherapy.
  
  
  METHODS
  Two prospective studies were performed: study A with 51 patients included different tumor sites and study B included 87 breast cancer patients. Acute reaction was assessed using the Radiation Therapy Oncology Group score. In both studies, patients were treated with curative radiotherapy, and the mean tumor dose applied was 55 Gy (40-65) +/- boost with 11 Gy (6-31) in study A and 50.4 Gy +/- boost with 10 Gy in study B. Individual radiosensitivity was determined with lymphocytes irradiated in vitro with X-ray doses of either 3 or 6 Gy and scoring the number of chromosomal deletions.
  
  
  RESULTS
  Acute reactions displayed a typical spectrum with 57% in study A and 53% in study B showing an acute reaction of Grade 2-3. Individual radiosensitivity in both studies was characterized by a substantial variation and the fraction of patients with Grade 2-3 reaction was found to increase with increasing individual radiosensitivity measured at 6 Gy (study A, p = 0.238; study B, p = 0.023). For study B, this fraction increased with breast volume, and the impact of individual radiosensitivity on acute reaction was especially pronounced (p = 0.00025) for lower breast volume. No such clear association with acute reaction was observed when individual radiosensitivity was assessed at 3 Gy.
  
  
  CONCLUSIONS
  Individual radiosensitivity determined at 6 Gy seems to be a good predictor for risk of acute effects after curative radiotherapy.
authors.affiliation: Clinic for Radiotherapy and Radiation Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Borgmann
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hoeller
authors.forename: Sven
authors.initials: S
authors.lastname: Nowack
authors.forename: Michael
authors.initials: M
authors.lastname: Bernhard
authors.forename: Barbara
authors.initials: B
authors.lastname: Röper
authors.forename: Sophie
authors.initials: S
authors.lastname: Brackrock
authors.forename: Cordula
authors.initials: C
authors.lastname: Petersen
authors.forename: Silke
authors.initials: S
authors.lastname: Szymczak
authors.forename: Andreas
authors.initials: A
authors.lastname: Ziegler
authors.forename: Petra
authors.initials: P
authors.lastname: Feyer
authors.forename: Winfried
authors.initials: W
authors.lastname: Alberti
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Dikomey
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D002278:Carcinoma in Situ / Q000473:pathology / Q000532:radiotherapy; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000532:radiotherapy; D002872:Chromosome Deletion; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011446:Prospective Studies; D011832:Radiation Injuries / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D011836:Radiation Tolerance / Q000235:genetics*; D011879:Radiotherapy Dosage; D018570:Risk Assessment