title: Risk of carotid blowout after reirradiation of the head and neck: a systematic review.
abstract: OBJECTIVE
  Carotid blowout (CB) is a rare but frequently fatal complication of head-and-neck (H&N) cancer or its treatment. We sought to determine the reported rate of CB in patients receiving salvage reirradiation for H&N cancer.
  
  
  METHODS
  A literature search identified 27 published articles on H&N reirradiation involving 1554 patients, and a pooled analysis was performed to determine the rate of CB. Treatment parameters, including prior radiation dose, interval from prior radiation, dose and fractionation of reirradiation, use of salvage surgery, and chemotherapy, were abstracted and summarized. The cumulative risk of CB was compared between groups using Fisher's exact test.
  
  
  RESULTS
  Among 1554 patients receiving salvage H&N reirradiation, there were 41 reported CBs, for a rate of 2.6%; 76% were fatal. In patients treated in a continuous course with 1.8-2-Gy daily fractions or 1.2-Gy twice-daily fractions, 36% of whom received concurrent chemotherapy, the rate of CB was 1.3%, compared with 4.5% in patients treated with 1.5 Gy twice daily in alternating weeks or with delayed accelerated hyperfractionation, all of whom received concurrent chemotherapy (p = 0.002). There was no statistically significant difference in the rate of CB between patients treated with or without concurrent chemotherapy, or between patients treated with or without salvage surgery before reirradiation.
  
  
  CONCLUSIONS
  Carotid blowout is an infrequent but serious complication of salvage reirradiation for H&N cancer. The rate of CB was lower among patients treated with conventional or hyperfractionated schedules compared with regimens of accelerated hyperfractionation, though heterogeneous patient populations and treatment parameters preclude definite conclusions. Given the high mortality rate of CB, discussion of the risk of CB is an important component of informed consent for salvage reirradiation.
authors.affiliation: Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202-5289, USA. mwmcdona@iupui.edu
authors.forename: Mark W
authors.initials: MW
authors.lastname: McDonald
authors.forename: Michael G
authors.initials: MG
authors.lastname: Moore
authors.forename: Peter A S
authors.initials: PA
authors.lastname: Johnstone
mesh_terms: D002339:Carotid Arteries / Q000528:radiation effects*; D020212:Carotid Artery Injuries / Q000209:etiology* / Q000401:mortality; D019583:Dose Fractionation, Radiation; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D006801:Humans; D011832:Radiation Injuries / Q000150:complications* / Q000401:mortality; D019233:Retreatment / Q000009:adverse effects; D012306:Risk; D012421:Rupture / Q000209:etiology / Q000401:mortality; D016879:Salvage Therapy / Q000009:adverse effects* / Q000379:methods