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Wakelkamp et al.,Amsterdam, The Netherlands, conducted a follow-up study to
assess mortality and retinal changes in 159 subjects who were treated with
orbital irradiation with or without additional corticosteroids (RT) for GO and in 86
subjects who were treated with corticosteroids only (CS). The mean follow-up of
both groups was 11 years. The mortality in RT was 27/159 (17 %) vs. 10/86 (12 %) in
CS (p=0.3). In 154 of the still living subjects retinal photographs were made.
Retinal changes were seen in 22/104 in RT and 1/50 in CS (21% vs. 2 %, p = 0.002).
Five subjects had severe retinopathy (3 patients had diabetes mellitus and 2
hypertension) and all had RT. In the other subjects with abnormal retinal photos,
5 or less haemorrhages and/or microaneurysms were present but visual equity was
normal. The authors conclude that radiotherapy for GO does not increase
mortality (none of RT group died from intracranial tumors). Radiotherapy induces
retinal changes of unknown clinical significance except in patients already at risk
for retinopathy. The authors caution for orbital irradiation in patients with
diabetes and/or hypertension. Moleti et al., Messina, Italy, evaluated the outcome of GO in 16 patients treated by radiotherapy (RT) in combination with corticosteroids and in 39 patients treated by total thyroidectomy (TT). The results of treatment were assessed within 6 months of treatment and between 12 and 18 months. In RT, GO worsened in short term follow-up in 6/16 (37.5 %) while at long term follow-up GO was worsened in 8/16 (50%). In TT these figures were 4/39 (10.2 %) and 18/39 (46.1%). From these results one can conclude that at long term no differences in results between the two treatments are evident. Baker et al., Cardiff, UK, and Munich, Germany, report worsening of GO (clinical activity score increasing from 1 to 6) after institution of the PPARg agonist pioglitazone for Type 2 diabetes, in a male patient who had stable GO for 2 years. After this observation the authors found in an in vitro model that pioglitazone produced a rapid and 8 to 12 fold increase in the production of preadipocytes which cells are presumed to play a vital role in the development of GO. They caution that patients treated with thiazolidinediones are at risk for worsening of eyesigns when they suffer from GO as well. Comment: Although this is a single case, to my opinion still important. Because apart from the clinical worsening of eyesigns during pioglitazone, this agent could also induce production of preadipocytes in vitro. As long as we do not know more about a possible direct effect of thiazolidinediones on GO, this compound should probably not be given to patients with GO certainly if activity of eye disease is still present. Rocchi et al., Pisa, Italy, investigated the long-term side effects in a total of 201 patients (female 151) who received radiotherapy for GO either by cobalt unit (CU) or by linear accelerator (LA). The median follow-up was 11 years (range 4–25 years). In the CU group the frequency of cataract vs. controls was increased in patients < 65 years of age (18.5% vs. 3.8 %, p=0.001). No increase was seen in this treatment group in patients = 65 years nor in all patients treated with AL. Radiation retinopathy was present in 4 (1.9 %) patients (3 treated with CU and 1 with AL) within two years after therapy. The authors conclude that there is no increased risk for cataract at all ages when treated with LA and in patients > 65 years when treated with CU. |
