Page 110 - Effects of radiotherapy and hyperbaric oxygen therapy on oral microcirculation Renee Helmers

Chapter 5
To our knowledge, Davoudi et al. performed the first clinical study that considered in vivo oral microcirculation parameters by looking at late irradiation effects. The investigators presented their concept using DOCT and svOCT for the first time to investigate blood flow and morphology parameters and demonstrated technical feasibility by comparing data of one late radiation toxicity patient to a healthy volunteer. Their data showed a significantly higher blood flow velocity (×1.8) and increased vessel volume density in irradiated tissue. Although it can be an advantage to measure blood flow and create reconstructed 3D images, the clinical application of DOCT and svOCT is currently cumbersome.8
Discrepancies in reports regarding microcirculatory alterations after RT make it difficult to compare data between studies directed at understanding the adverse effects of HN irradiation. Standardized data acquisition procedures are necessary for providing reliable clinical assessments of irradiation-induced side effects and facilitates identifying correlations associated with different pathologies, i.e. mucositis, atrophy and tissue necrosis. Ideally a future scoring system should include systematic clinical assessments of irradiation injury severity based on microcirculatory parameters.
A limitation of this study was not correlating microcirculatory parameters to clinical pathology. In our study, 5 (17%) out of 30 patients presented with oral lesions, unfortunately these numbers are too small to detect any robust correlations. Comparing microcirculatory parameters of irradiated tissue with no clinically visible signs of pathology and tissue with clinical pathology (e.g. ulceration, dry mouth, osteoradionecrosis) could expose a transition phase in microcirculation between the two. Identifying microcirculatory differences in this transition phase could offer a window of opportunity in which potential adjunctive therapies (e.g. hyperbaric oxygen therapy) could ameliorate altered irradiated tissue states. As a clear difference in oral microcirculatory parameters between irradiated tissue and control tissue was presented in this study, further research should be aimed at exposing this microcirculatory transition phase between irradiated tissue with and without clinical pathology in which the CytoCam can serve an important diagnostic role for monitoring microcirculation parameters at patient side.
Next to the opportunity for determining tissue state in a chairside setting, therapy can be targeted towards these subclinical parameters and equally monitored for treatment response. In this light, it is important to describe the microcirculation to further identify its value as a clinical parameter.
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