Page 111 - Effects of radiotherapy and hyperbaric oxygen therapy on oral microcirculation Renee Helmers

Late radiation-induced oral microvascular changes
Inasmuch as microvascular pathologies are studied, it must be considered
that systemic conditions such as hypertension and diabetes mellitus may
increase adverse effects on microcirculation since vascular health is already
potentially compromised. Comorbidities should therefore be reported as has
been performed in this study. To this end, it can be argued that in our study no
distinction was made between patients that received chemoradiotherapy (CRT)
or RT alone. Although the effect of CRT on long-term side effects is not entirely
clear, a systematic review conducted by Nabil et al. found no increased risk of
ORN compared to only RT.21 However, subtle effects on the microcirculation
might be overseen when no distinction is made. With respect to ORN, the measurements in this study were only conducted on the mandibular gingiva.
The rationale behind this restriction in site lies in the higher prevalence of
ORN in the mandible due to differences in blood perfusion compared with the
maxilla.16,21 Moreover, HNCP referred for hyperbaric oxygen therapy had a higher
prevalence of irradiation on the mandible due to the highest predilection of
HN squamous cell carcinoma on tongue and the floor of the mouth.31 Another
interesting point to consider is that dental status may be an influencing factor
on gingival capillary density as edentulous areas may differ compared to 5 dentate areas. The role of plaque accumulation and microorganism load may
further influence gingival capillary density. Currently, no data linking gingival capillary density measurements and microbial status and/or edentulous vs. dentate areas exist. Further microcirculatory investigations are warranted before insightful conclusions can be drawn.
CONCLUSIONS
This study shows the clinical feasibility in detecting tissue-specific microcirculatory alterations in irradiated oral tissues in HNCP. Unique to this study is the capability of subclinically measuring reduced capillary density and large blood vessel diameters in HNCP in relation to late irradiation pathology. Further studies should be aimed at developing a systematic scoring system for identifying the severity of late microcirculatory irradiation damage in correlation with clinical radiation injury. Describing in vivo parameters of different stages of disease could be more valuable if microcirculatory measurements were included to support diagnosis involving pathophysiological processes and evaluations of therapeutic efficacy.
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