Interventional Procedures Consultation Document - Retrobulbar irradiation for thyroid eye disease


Interventional Procedure Consultation Document

Retrobulbar irradiation for thyroid eye disease

The National Institute for Health and Clinical Excellence is examining retrobulbar irradiation for thyroid eye disease and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about retrobulbar irradiation for thyroid eye disease.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

  • comments on the preliminary recommendations
  • the identification of factual inaccuracies
  • additional relevant evidence.

Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that the Institute will follow after the consultation period ends is as follows.

  • The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
  • The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.

For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (

Closing date for comments: 26 July
Target date for publication of guidance: November 2005

Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.

1 Provisional recommendations

Current evidence on the safety and efficacy of retrobulbar irradiation for thyroid eye disease appears adequate to support the use of this procedure in patients for whom other treatments are inadequate or associated with troublesome side effects. Normal arrangements should be in place for consent, audit and clinical governance.


Patient selection should be made with the involvement of a multidisciplinary team that includes an ophthalmologist and a specialist in radiotherapy.

2 The procedure
2.1 Indications
2.1.1 Thyroid eye disease (also known as dysthyroid eye disease, Graves' eye disease, Graves' ophthalmopathy, or thyroid orbitopathy) is a disease that affects the extraocular muscles and other orbital tissues. It is the most common cause of unilateral or bilateral proptosis in adults, due to enlarged eye muscles and an increase in the fatty tissue behind the eyes.
2.1.2 Other symptoms include diplopia, soreness and grittiness of the eyes with increased watering and photophobia. In patients with more severe disease, the eyelids may not close properly and this can result in corneal exposure and ulceration. In addition, the increased orbital tissue may cause optic nerve compression with resultant damage to sight.
2.1.3 Steroid medication is the most commonly used treatment for thyroid eye disease. This decreases inflammation in the eye muscles and orbital tissue. Often, high-dose systemic corticosteroids are required, but these have significant side effects. Recurrence of active eye disease after treatment may necessitate consideration of other therapeutic options.
2.1.4 Surgical orbital decompression is a method of relieving severe pressure on the optic nerve. Various surgical procedures may be used to make room in the eye socket for the swollen and thickened orbital tissue. This allows the bulging eyeball to return to its normal position.

Radiation therapy targeted at the tissue behind the eyeball aims to decrease orbital inflammation. Orbital irradiation may be used alone or in combination with steroids.

2.2 Outline of the procedure

Patients are commonly treated on an outpatient basis. The patient is placed in a supine position, and the head fixed with a full head shell. Irradiation is targeted at the retrobulbar contents of the orbit, and the calculated dose is delivered in about 10 sessions over a 2-week period.

2.3 Efficacy

A randomised cross-over trial of 42 patients, with either the left or right eye treated first, found no significant differences between eyes treated with irradiation and those receiving sham treatment in outcomes of muscle volume and proptosis at 3 months following treatment.

2.3.2 A randomised controlled trial of irradiation versus sham therapy in 88 patients with mild, untreated thyroid eye disease found a greater response rate with irradiation, using a composite outcomes measure of eye function and physical properties (p = 0.02, 52% versus 27%).
2.3.3 In a randomised controlled trial of 60 patients, improvement in eye motility was achieved in 82% (14/17) of patients following irradiation, and in 27% (4/15) of patients following sham therapy (p = 0.004). At 24 weeks, eye elevation was improved by 4.9 more in the patients treated with irradiation (p = 0.01). There were no significant differences in proptosis or eyelid swelling between the study arms.
2.3.4 When irradiation and prednisolone were compared in a randomised controlled trial, there were no significant differences in eye function between the treatment arms, as measured by proptosis, visual acuity or eyelid aperture size. Self-reported eye-evaluation scores were also similar between the two groups at 24 weeks. For more details, refer to the sources of evidence (see Appendix).

The Specialist Advisors noted that efficacy was hard to assess due to the natural history of the condition.


2.4 Safety

Two case series with long-term follow-up of 7.2 and 11 years recorded the incidence of cataracts to be between 10% (21/204) and 11% (22/197), and reported retinopathy in 1% (2/197 and 2/204) of patients. One series found tumours in 5% (10/197) of patients treated with irradiation but none of these were located within the area treated. Another case series found no malignant tumours in the head or neck in 157 patients followed-up for a median 11 years. Mucosal thickening or polyps in the paranasal tissue were recorded in 34% (53/157) of patients followed up by CT scans. For more details, refer to the sources of evidence (see Appendix).

2.4.2 The Specialist Advisors noted that theoretical adverse events include short-term exacerbation of thyroid eye disease, dry eye, cataract, retinopathy (particularly in diabetic patients) and carcinogenesis.

Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
July 2005

Appendix: Sources of evidence

The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.

  • Interventional procedure overview of retrobulbar irradiation for thyroid eye disease, April 2005

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This page was last updated: 04 February 2011