Radiation for TED

Here is a study from Mayo Clinic, published 1999.

A prospective, randomized, double-blind controlled study of orbital radiotherapy for Graves' ophthalmopathy.

Background:

Although widely used for treatment of Graves' ophthalmopathy (GO), the efficacy of orbital radiotherapy (OT) has not been established in a prospective randomized double-blind controlled trial.

Specific aims: To determine:

1) If 20 Gy of external beam OT directed to one orbit of patients with GO resulted in improvement in comparison with the untreated orbit when evaluated three and six months after therapy;

2) If 20 Gy of OT to the second orbit six months later produced effects similar to those observed when the first orbit was treated;

3) To relate the magnitude of the treatment effect to the time since onset of eye symptoms.

Patients and Methods:

Forty-two euthyroid patients with mild to moderate GO and elevated TSI levels received 20 Gy of megavoltage radiation to a randomly selected orbit.

Six months later the second orbit was treated.

Every three months, measurements were made of thyroid function and antibody status, proptosis, volume of extraocular muscle (EOM) and fat, range of EOM motion, eyelid fissures and extent of diplopia.

The study had 80% power to detect 0.5 mm change in proptosis and 0.75 mL in volume measures.

Results:

Six month - baseline measurements were recorded for the untreated (UT) and the treated (T) orbit.

They revealed (mean±SD):
Fat volume(cc) UT -0.3(1.3), T 0.3(1.3), P 0.87.
Muscle volume(cc) UT -0.4(1.3), T -0.6(1.4), P 0.14.
Proptosis(mm) UT 0.0(1.0), T -0.1(1.3), P 0.46.
Range of motion area (cm2) UT 8.7 (33), T 8.8(35), P 0.98.
Lid fissures(mm) UT 0.0(2.0), T -0.1(1.7), P 0.42.

Results at three months were similar to those at six months.

Diplopia field area at baseline, six and 12 months was 42, 41, and 39 cm2. P=0.09 for six months - baseline and 0.02 for 12 months - baseline.

Subset analyses of early vs. late treated orbits, or smokers vs. non-smokers, and of patients treated <1.3 vs. >1.3 years since onset disclosed no significant differences for any group.

With one exception, patients were euthyroid on commencing and throughout the study.

Conclusion:

If radiotherapy is beneficial for Graves' ophthalmopathy, its ameliorative effects did not reach the detection level of the techniques used in this study.

No clinically significant benefit was observed.

The paper below analyzes results obtained from two different radiation procedures used for Graves' orbitopathy. They show that only some improvement was obtained for double vision, whereas bulging (proptosis), eyelids swelling, and all other variables remained unchanged.

Lancet 2000 Apr 29;355(9214):1505-9

Radiotherapy for Graves' orbitopathy: randomised placebo-controlled study.

Mourits MP, van Kempen-Harteveld ML, Garcia MB, Koppeschaar HP, Tick L, Terwee CB Donders Institute of Ophthalmology (Orbital Unit), University Medical Centre, Utrecht, The Netherlands.

Background:

The best treatment (steroids, irradiation, or both) for moderately severe Graves' orbitopathy, a self-limiting disease is not known.

We tested the efficacy of external beam irradiation compared with sham-irradiation.

Methods:

In a double-blind randomised clinical trial, 30 patients with moderately severe Graves' orbitopathy had radiotherapy (20 Gy in ten fractions), and 30 were assigned sham-irradiation (ten fractions of 0 Gy).

Treatment outcome was measured qualitatively by changes in major and minor criteria and quantitatively in several ophthalmic and other variables, such as eyelid aperture, proptosis, eye movements, subjective eye score, and clinical-activity score at 24 weeks.

Findings:

The qualitative treatment outcome was successful in 18 of 30 (60%) irradiated patients versus nine of 29 (31%) sham-irradiated patients at week 24 (relative risk [RR]=1.9 [95% CI 1.0-3.6], p=0.04).

This difference was caused by improvements in diplopia grade, but not by reduction of proptosis, nor of eyelid swelling.

Quantitatively, elevation improved significantly in the radiotherapy group, whereas all other variables remained unchanged.

The field of binocular single vision was enlarged in 11 of 17 patients after irradiation compared with two of 15 after sham-irradiation. Nevertheless, only 25% of the irradiated patients were spared from additional strabismus surgery.

Interpretation:

In these patients with moderately severe Graves' orbitopathy, radiotherapy should be used only to treat motility impairment.