title: Effects of preoperative conventional and hyperfractionated radiotherapy on the healing of rat colonic anastomoses.
abstract: BACKGROUND
  One problem associated with end to end anastomoses after preoperative radiotherapy is leakage. The strength of the anastomoses is very important. Fractionation schedules are widely under investigation to achieve higher doses with less toxicity and high curative potential. The aim of this study was to compare preoperative conventional and hyperfractionated radiotherapy effects on anastomoses.
  
  
  METHODS
  Sixty Wistar albino rats were divided into 3 groups: control, conventional radiotherapy (2 Gy/fraction, total 44 Gy), and hyperfractionated radiotherapy (1.2 Gy/fraction, total 52.8 Gy). 5 weeks after completion of the treatment, the rats underwent end to end anastomoses to the rectum. Following the surgery, the bursting pressure of the anastomoses and the hydroxyproline levels were measured on days 3 and 7.
  
  
  RESULTS
  The bursting pressure was lower in both radiotherapy groups on the 3rd day. On day 7, the results of the conventional radiotherapy arm matched those of the control group, but the results of the hyperfractionated group did not (p = 0.001). On day 3, hydroxyproline levels were significantly lower in both radiotherapy groups than in the control group (p = 0.001). On the 7th day, the statistical difference disappeared within the radiotherapy groups. However, the hydroxyproline levels of the 2 radiotherapy arms were still lower than those of the control group (p = 0.001).
  
  
  CONCLUSIONS
  Hyperfractionation strongly inhibits collagen synthesis and is associated with protracted healing.
authors.affiliation: Department of General Surgery, Gazi Hospital, Samsun, Turkey.
authors.forename: Mahmut Fikret
authors.initials: MF
authors.lastname: Gursel
authors.forename: Zafer
authors.initials: Z
authors.lastname: Malazgirt
authors.forename: Bilge
authors.initials: B
authors.lastname: Gursel
authors.forename: Saban
authors.initials: S
authors.lastname: Cakir
authors.forename: Zafer
authors.initials: Z
authors.lastname: Eren
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Isildak
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods*; D000818:Animals; D003106:Colon / Q000528:radiation effects* / Q000601:surgery*; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D011300:Preoperative Care / Q000379:methods; D018714:Radiotherapy, Adjuvant / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D016896:Treatment Outcome; D014945:Wound Healing / Q000528:radiation effects*