Radiotherapy only in severe, progressive endocrine orbitopathy: long-term results and comparison of various classification systems

Abstract

Therapeutic results after radiotherapy in thyroid associated orbitopathy (TAO) often are not comparable, because either different therapeutic methods at the same time or different scores were used in the evaluation. This study focuses on radiotherapy alone by means of different evaluation scores. 60 patients (49 women, 11 men) received standard external beam radiotherapy (20 Gy: 10 fractions of each 2 Gy) as ultima ratio after failing different other therapies of thyroid associated orbitopathy. The mean interval from beginning of the symptoms to the radiotherapy was 17 +/- 36 months (between 6 and 240 months). The follow up was documented--classified by means of 4 different scores--before radiotherapy, 6-12 weeks, 1 year after radiotherapy and at last follow up. The changes of symptom categories or grades of the different scores were analysed. Significant changes of the ophthalmic scores were observed when comparing the endpoints at 6-12 weeks, and at 1-year follow up after radiotherapy. The "classical" Werner score at 12 months follow up did not correlate well with the other TAO scores: American thyroid association (ATA) scoring system, Stanford scoring system, International ophthalmopathy index, while all other TAO scores revealed a high correlation among each other. According to the Orbitopathy Index (OI) of Grussendorf an improvement from 14.2 points to 6.0 points was achieved. Soft tissue involvement and corneal involvement demonstrated the highest response rate (83/87%), extraocular muscle involvement and proptosis a good response rate (69/70%). No long-term complications were observed. According to this study there are indications that external beam radiotherapy is a suitable therapy even after pretreatment and a longer course of TAO. The OI, the ATA and the Stanford scoring systems lead to similar results in the assessment of thyroid orbitopathy.