title: Hyperbaric oxygen therapy for late radiation-associated tissue necroses: is it safe in patients with locoregionally recurrent and then successfully salvaged head-and-neck cancers?
abstract: OBJECTIVE
  To test, in a retrospective matched-pair study, whether necrosis-rescuing hyperbaric oxygen therapy (HBOT) increases the risk of cancer re-recurrence in patients with locoregionally recurrent and then successfully salvaged head-and-neck cancers.
  
  
  METHODS
  Between January 1995 and July 2004, we retrospectively identified 22 patients with locoregionally recurrent and then successfully salvaged head-and-neck cancers. We defined two groups: the HBOT group, 11 patients with HBOT for rescuing late radiation-associated tissue necroses; and the non-HBOT group, the other 11 matched-pair patients without HBOT. Between the two groups, the following four factors were matched for case pairing: primary cancer subsite, initial cancer stage, age, and gender.
  
  
  RESULTS
  Three findings indicate that HBOT increases the risk of cancer re-recurrence. First, we observed more cancer re-recurrences in the HBOT group than in the non-HBOT group: 9 of 11 vs. 4 of 11, with 5-year disease-free survival rates after salvage of 32.7% vs. 70.0% (hazard ratio 3.2; 95% confidence interval 1.03-10.7; p = 0.048). Second, re-recurrences developed rapidly after HBOT in 6 patients. Third, 3 patients had unusual cancer re-recurrences after HBOT. Remarkably, of 9 patients with cancer re-recurrences in the HBOT group, 4 patients had cancer disease-free intervals of 9 months or less before HBOT.
  
  
  CONCLUSIONS
  Necrosis-rescuing HBOT should be given with caution in patients with locoregionally recurrent and then successfully salvaged head-and-neck cancers; if it cannot be omitted entirely, deferring HBOT 9 months or longer after cancer re-treatment may be prudent.
authors.affiliation: Department of Radiation Oncology, Buddhist Tzu Chi General Hospital, Dalin Branch, Taiwan, Republic of China.
authors.forename: Hon-Yi
authors.initials: HY
authors.lastname: Lin
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Ku
authors.forename: Dai-Wei
authors.initials: DW
authors.lastname: Liu
authors.forename: Hsing-Lung
authors.initials: HL
authors.lastname: Chao
authors.forename: Chun-Shu
authors.initials: CS
authors.lastname: Lin
authors.forename: Yee-Min
authors.initials: YM
authors.lastname: Jen