Page 128 - Effects of radiotherapy and hyperbaric oxygen therapy on oral microcirculation Renee Helmers

Chapter 6
often are (former) smokers. Awareness of the influence of these comorbidities and their compromising effect on the microvascular state and tissue perfusion ahead of enduring (chemo-) radiotherapy (CRT) should be considered and interpreted in context with clinical outcomes and potential supportive care. Measurable effects of (former) smoking and diabetes on oral microcirculation were previously described.9,24 The potential resuscitating effect associated with HBOT on late IR injury of the microcirculation could therefore be altered or even latent. The percentage of former smokers in this study was notably low compared with other reports and therefore might concern an underreported observation.19,33 However, our results did not show an association of former smoking and the effect of HBOT on microvascular IR injury over a period of 6 months. Additionally, no significant difference in patients with CRT compared with RT alone was found between the time points for all microcirculation parameters. Another point of consideration is that the number of patients in this study are not sufficient to divide into subgroups based on comorbidities to extract potential subtle differences in adverse effects on the microcirculation. Furthermore, the maxillary gingiva was excluded from observation as prevalence of substantial IR on the maxilla was scarce in the HNCP that were referred for HBOT. A further explanation indicates that the highest predilection of squamous cell carcinoma in the HN region is on the tongue and floor of the mouth.37 Finally, although accumulation of plaque could hypothetically influence observed gingival capillary density, no significant association with edentulism and effect of HBOT on gingival FCD was detected in our study.
The present study reports a measurable effect of HBOT in the oral microcirculation of previously irradiated tissue. Future studies should be directed at correlating microvascular parameters to clinical appearance of IR tissue injury. Stages of emerging oral tissue necrosis linked to the state of the microcirculation should be identified and scored. Chairside appraisal of the oral microcirculation in an individual patient could determine in-vivo the severity of vascular IR injury that is present, monitor the efficacy of HBOT and consequently direct timing and duration specified to response of the oral tissue requiring supportive care or treatment. Therefore, monitoring microcirculation provides an opportunity to detect emerging pathophysiology in an early state so that supportive therapies could prevent progression of late IR tissue injury to the mutilating and difficult to treat ORN in the HN region. Time-consuming and (relatively) costly HBOT (~€5,000 - €10,000 per patient; average of 30
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