title: Do inflammatory processes contribute to radiation induced erythema observed in the skin of humans?
abstract: BACKGROUND
  Two prospective trials were designed to determine whether there may be a role for inflammatory mediators in human skin erythema at both high and low doses per fraction and for 'out of field' effects.
  
  
  METHODS
  Trial 1. Effects of topical indomethacin (1%) and hydrocortisone (1%) applied before and during radiotherapy were compared for erythema induced by 20 Gy in four fractions (n = 26, 6 MV). Trial 2. Effects of topical hydrocortisone (1 %) applied before and during radiotherapy and no medication were compared for erythema induced by 1, 3, 5 and 7 Gy in five fractions (n = 21, 120 kV). Erythema was measured using reflectance spectrophotometry (RFS) and laser Doppler (LD) on a weekly basis.
  
  
  RESULTS
  Trial 1. A bi-phasic reaction time course was suggested in two-thirds of the cases. The first phase did not appear to be influenced by hydrocortisone cream but the second was significantly attenuated. Indomethacin had no effect on either reaction phase. Erythema measured several centimetres outside of the field was reduced by hydrocortisone but not by indomethacin. Trial 2. Trial 2 confirmed the presence of measurable erythema, invisible to the eye, that coincided in its time course to the first phase of erythema noted in trial 1. This reaction was more intense than predicted by the LQ formula and was non-significantly attenuated by topical hydrocortisone. RFS readings proved to be less subject to inter- and intra-patient variations than the LD unit used.
  
  
  CONCLUSIONS
  Inflammatory responses may play a role in the mediation of the erythematous response to radiation in human skin. Further studies are warranted.
authors.affiliation: Department of Oncology, Kuopio University Hospital, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Simonen
authors.forename: C
authors.initials: C
authors.lastname: Hamilton
authors.forename: S
authors.initials: S
authors.lastname: Ferguson
authors.forename: P
authors.initials: P
authors.lastname: Ostwald
authors.forename: M
authors.initials: M
authors.lastname: O'Brien
authors.forename: P
authors.initials: P
authors.lastname: O'Brien
authors.forename: M
authors.initials: M
authors.lastname: Back
authors.forename: J
authors.initials: J
authors.lastname: Denham
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use; D019583:Dose Fractionation, Radiation; D004333:Drug Administration Routes; D004890:Erythema / Q000188:drug therapy / Q000209:etiology* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006854:Hydrocortisone / Q000008:administration & dosage / Q000627:therapeutic use; D007213:Indomethacin / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000532:radiotherapy*; D015588:Observer Variation; D010166:Palliative Care / Q000379:methods; D011446:Prospective Studies; D011855:Radiodermatitis / Q000188:drug therapy / Q000209:etiology* / Q000473:pathology; D012867:Skin / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects*
chemical_list: D000893:Anti-Inflammatory Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D006854:Hydrocortisone; D007213:Indomethacin