Clinical and Dosimetric Variables Related to Outcome After Treatment of Graves' Disease With 550 and 1110 MBq of I-131

Autor(es)

Sapienza, Marcelo Tatit ^[1] ; Coura-Filho, George Barberio ^[1] ; Willegaignon, Jose ^[1] ; Watanabe, Tomoco ^[1] ; Duarte, Paulo Schiavom ^[1] ; Buchpiguel, Carlos Alberto ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Med, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CLINICAL NUCLEAR MEDICINE; v. 40, n. 9, p. 715-719, SEP 2015.
• Citações Web of Science: 3

Resumo

Therapy of Graves' hyperthyroidism (HTG) with I-131 is still mostly performed on an empirical basis. The present study was carried out to evaluate clinical and dosimetric variables associated with outcome in HTG therapy, which could contribute to planning and defining the most appropriate activity to be administered. Methods Patients with HTG were randomly assigned to therapy with 555 MBq (15mci) or 1110 MBq (30 mCi) of I-131. Estimation of thyroid radiation absorbed dose was made according to MIRD methodology. Success was defined as clinical/laboratory euthyroidism or hypothyroidism one year after therapy. The association between clinical, laboratory, and dosimetric variables with 1-year outcome was measured using bivariate analysis, followed by logistic regression. Results Ninety-one patients included completed the follow-up. Therapeutic success was observed in 77 (84.6%) of them, in a greater proportion when 1110 MBq of I-131 was administered as compared with 550 MBq (94.8% vs 77.4%, P = 0.02). Besides administered activity, multivariate analysis indicated that outcome was related to patient age and gland mass. A higher therapeutic success rate was achieved with doses greater than 300 Gy as compared with doses less than 300 Gy (89% vs 60%, P = 0.01). Conclusion Administered activity, age, and gland mass were related to the outcome. Radiation absorbed dose, although not significant according to multivariate analysis, may be used as a quantitative parameter in therapy planning, with a target dose of 300 Gy. In cases where a rapid and efficient response to radioiodine treatment is required, adoption of a simplified protocol employing high activities is justified. (AU)

• Processo FAPESP: 08/04504-5 - Avaliação da eficácia de radioiodoterapia com 15 mCi e 30 mCi de iodo-131 no tratamento da doença de Graves: estudo prospectivo randomizado
• Beneficiário: Marcelo Tatit Sapienza
• Modalidade de apoio: Auxílio à Pesquisa - Regular