Radioiodine therapy and Graves' disease - Myths and reality

• Published in: PloS one Vol. 15; no. 1; p. e0226495
• Main Authors: Plazinska, Maria Teresa, Sawicka-Gutaj, Nadia, Czarnywojtek, Agata, Wolinski, Kosma, Kobylecka, Małgorzata, Karlińska, Maria, Prasek, Karolina, Zgorzalewicz-Stachowiak, Małgorzata, Borowska, Magdalena, Gut, Paweł, Ruchala, Marek, Krolicki, Leszek
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01-01-2020; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Anti-Inflammatory Agents - therapeutic use; Biology and Life Sciences; Cigarette Smoking; Cigarettes; Connective tissues; Drug dosages; Endocrinology; Environmental factors; Female; Graves Disease - drug therapy; Graves Disease - radiotherapy; Graves Ophthalmopathy - diagnosis; Graves Ophthalmopathy - drug therapy; Graves' disease; Humans; Hyperthyroidism; Hyperthyroidism - diagnosis; Hyperthyroidism - pathology; Internal medicine; Iodine; Iodine 131; Iodine radioisotopes; Iodine Radioisotopes - chemistry; Iodine Radioisotopes - metabolism; Male; Medical records; Medical services; Medicine and Health Sciences; Metabolism; Middle Aged; Muscles; Nuclear medicine; Oculomotor system; Outpatient care facilities; Pathogenesis; Patients; Physical Sciences; Prednisone; Prednisone - therapeutic use; Prophylaxis; Radiopharmaceuticals - chemistry; Radiopharmaceuticals - metabolism; Radiopharmaceuticals - therapeutic use; Recurrence; Retrospective Studies; Signs and symptoms; Smoking; Social Sciences; Statistical analysis; Steroids; Supervision; Therapy; Thyroid; Thyroid gland; Thyrotropin - blood; Thyroxine - blood; Triiodothyronine - blood; Young Adult; Poland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0226495

Autoimmune reactions in Graves' disease (GD) occur not only in the thyroid gland, but also in the orbital connective tissue, eyelids, extraocular muscles. The occurrence of orbitopathy in the course of GD is influenced by environmental factors, e.g. cigarette smoking.
The aim of the study was to analyze the effect of cigarette smoking on the efficacy of activity of radioiodine(131I) therapy in patients with GD. We also studied the influence of cigarette smoking and the efficacy of prednisone prophylaxis on the risk of thyroid-associated ophthalmopathy (TAO) development after radioiodine therapy (RIT) during two years of follow-up.
Medical records of hyperthyroid patients treated with radioiodine had been included. Patients were scheduled to visit outpatient clinics at baseline and 1, 3, 6, 9, 12, 18, and 24 months after RIT.
The studied group consisted of 336 patients (274 women, 62 men) diagnosed with GD and treated with RIT; 130 patients received second therapeutic dose of 131I due to recurrent hyperthyroidism. Among all studied patients, 220 (65.5%) were smokers and 116 (34.5%) non-smokers. In the group of smokers 115 (52.2%) of patients received single RIT, 105 (47.8%) received second dose of RAI due to recurrent hyperthyroidism. In non-smokers 91 (78.6%) received single activity of RAI, while 25 (21.4%) patients required second RIT due to recurrent hyperthyroidism. The ophthalmic symptoms in the group of smokers after RIT were less frequent, if the patient received preventative treatment in the form of oral prednisone (P = 0.0088).
The results of our study suggest that cigarette smoking reduces the efficacy of treatment with 131I in patients with GD. The study also confirmed the effectiveness of steroid prophylaxis against TAO development or exacerbation after RIT.