Breakdown of the blood-eye barrier in choroidal melanoma after proton beam radiotherapy
Irradiation of choroidal melanoma is a safe and globe preserving procedure. Chronic inflammatory processes and ischemia are the main reasons for secondary enucleation in the long run. The aim of this study was to determine whether intraocular inflammation and especially inflammatory response after proton beam therapy (PBT) is related to primary tumor characteristics such as height, tumor volume, and initial flare values.
Twenty-six patients treated for uveal melanoma using PBT were included. All patients were examined for signs of inflammation using laser flare photometry (LFP). Each examination included assessment of the melanoma and fellow eye (which acted as the control) and imaging of the melanoma.
Significant differences of flare values between melanoma eyes and control group were found both at baseline (median 17.65 ph/ms (min 4, max 37.10), 7.45 ph/ms (min 0.80, max 16.40), respectively) and during follow-up (median 21.45 ph/ms (min 4.5, max 70.90); 6.05 ph/ms (min 2.40, max 16.40), respectively) (p < 0.001, Wilcoxon test). Flare values in melanoma eyes increased significantly after PBT (p = 0.005, Wilcoxon test) and after a follow-up of 94 days (median, 7–420 days). Flare values of the control group did not change (p = 0.946, Wilcoxon test). The increase of flare values correlated significantly with maximum tumor height and volume (Spearman-Rho 0.633, p = 0.001 and 0.519, p = 0.007, respectively).
LFP has proven to show significantly higher flare values in melanoma eyes as compared with the control group and provides data on the course of the inflammatory response after treatment. It may ease treatment planning both at baseline and during follow-up.
KeywordsChoroidal melanoma Proton beam radiotherapy Inflammatory response Breakdown blood-aqueous barrier Flare meter
Compliance with ethical standards
Conflicts of interest
The authors declare that they have no conflict of interest.
Ethical approval and informed consent
IRB approval was obtained. All procedures performed in studies involving human participants were in accordance with the ethical standards of the IRB Charité–Universitätsmedizin Berlin (EA4/095/15) and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent from all patients was obtained.
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