Effect of orbital radiotherapy on the outcome of surgical orbital decompression for thyroid-associated orbitopathy (TAO): a retrospective study in 136 patients

Orbital Radiation for Thyroid Eye Disease: A Report by the American Academy of Ophthalmology

PURPOSE

To review the current literature on the safety and efficacy of orbital radiation for the management of thyroid eye disease (TED).

METHODS

A literature search was conducted last in February 2021 of the PubMed database to identify all articles published in the English language on original research that assessed the effect of orbital radiation on TED. The search identified 55 articles, and 18 met the inclusion criteria for this assessment. A panel methodologist then assigned a level of evidence rating for each study, and all of them were rated level III.

RESULTS

Two large retrospective studies demonstrated the efficacy of radiation treatment, with or without corticosteroid use, in preventing or treating compressive optic neuropathy (CON). Three studies highlighted the role of orbital radiation therapy (RT) to facilitate the tapering of corticosteroids. Several other studies showed a possible role for RT to improve diplopia and soft tissue signs.

CONCLUSIONS

Although no level I or level II evidence exists, the best available evidence suggests that orbital radiation, used with or without corticosteroids, is efficacious in preventing CON, improving motility restriction, and decreasing clinical activity in TED. Orbital radiation also may facilitate a corticosteroid taper. Together, these studies show that RT seems to modify the active phase of TED. Short-term risks of orbital radiation are minor, but long-term outcome data are lacking.

Evidence That Baseline Levels of Low-Density Lipoproteins Cholesterol Affect the Clinical Response of Graves' Ophthalmopathy to Parenteral Corticosteroids

BACKGROUND

High dose intravenous glucocorticoid (ivGC) therapy is the first line treatment in moderate to severe Graves' ophthalmopathy (GO) and is associated with a clinical response rate ranging from 50% to 80%. Recently, a positive correlation between total cholesterol and low-density lipoproteins cholesterol (LDLc) with GO presentation and activity has been described.

OBJECTIVE

We aimed at evaluating whether, in patients with moderate to severe active GO treated with ivGC therapy, cholesterol, and LDLc could represent valuable predictive factors of medium-term GO outcome.

METHODS

This single center retrospective study was conducted in a consecutive series of 87 patients undergone ivGC therapy because affected by moderate to severe active GO. Clinical outcome of GO was evaluated at week 6 (W6) and 12 (W12) in respect to baseline conditions (week 0) by the seven points CAS according to EUGOGO recommendations. Univariate analysis and binary logistic regression were performed for the outcome variable W12CAS.

RESULTS

In patients with active GO, an early positive clinical response to ivGC therapy (as evaluated by CAS at 6W) was a strong determinant (OR=13) of the clinical outcome at week 12. Moreover, high levels of LDLc at baseline were positively associated with a reduction in the likelihood of being classified as improved at 12W. Patients with LDLc >193.6 mg/dl were very likely to respond negatively to ivGC therapy independently from the response at 6W. Based on these results, we propose a predictive decision-making model to be tested in future prospective studies.

DISCUSSION

We found that, in patients with active GO, both an early clinical response to ivGC therapy and baseline LDLc levels are significant determinants of GO outcome (W12CAS). These data support the need of a cholesterol-lowering treatment before addressing these patients to ivGC therapy.