title: Lithium as an adjuvant in the postoperative ablation of remnant tissue in low-risk thyroid carcinoma.
abstract: BACKGROUND
  Thyroid remnant ablation (RA) with 30 mCi of radioactive iodine (131I) in patients thyroidectomized for treatment of low-risk differentiated thyroid carcinoma (DTC) has a success rate of 64% to 84%. Lithium increases the residence time of 131I in the thyroid tissue. The aim of this study was to determine if lithium treatment added to 30 mCi 131I would enhance the success rate of this treatment compared with 30 mCi 131I alone in patients who were thyroidectomized for treatment of low-risk DTC.
  
  
  METHODS
  This was a randomized study with endpoint at one year. Sixty one consecutive patients were enrolled and randomized into two groups: group A (n=32) treated with 30 mCi 131I; group B (n=29) treated with 30 mCi 131I plus an oral dose of lithium 900 mg/day, for 7 days. All patients were evaluated by whole body scan (WBS) with 123I and had serum TSH, thyroglobulin (Tg), and anti-Tg antibodies (TgAb) determined when they were hypothyroid on no thyroid hormone. Patients were reevaluated after one year with serum TSH, Tg, and TgAb determinations and WBS with 123I. The criteria for defining a successful outcome was a negative WBS and a serum Tg of <1.
  
  
  RESULTS
  Group A was composed of 28 women and four men (ages 25-71 years) with 2 having follicular thyroid carcinoma (FTC), 22 having papillary thyroid carcinoma (PTC) of 1-4.5 cm, and 8 having micro PTCs (mPTC) of 0.3-0.8 cm. Group B was composed of 26 women and 3 men (ages 20-63 years) with 3 having FTC, 15 having PTC of 1.2-3.5 cm, and 11 having mPTC of 0.2-0.8 cm. All patients had a history of a WBS after their post-therapeutic 131I dose that showed uptake in the cervical region. After one year, 22 patients from group A had a negative WBS (68.75%) and in group B, 27 patients had a negative WBS (93.1%). The successful rates for the follow-up WBS were significantly different (p=0.017). There were 19 patients in group A in whom the initial Tg was positive. Of these, 14 had a negative follow-up Tg (73.7%). Group B had 9 patients with a positive initial Tg and all of them had a negative follow-up Tg (100%).
  
  
  CONCLUSIONS
  The addition of lithium to treatment with 30 mCi 131I in thyroidectomized patients with low-risk DTC improved the efficacy of thyroid RA and therefore might be a better alternative than using higher doses of 131I for remnant ablation in these patients.
authors.affiliation: Division of Endocrinology, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
authors.forename: Claudia Akemi
authors.initials: CA
authors.lastname: Yamazaki
authors.forename: Rosalia P
authors.initials: RP
authors.lastname: Padovani
authors.forename: Rosa Paula Mello
authors.initials: RP
authors.lastname: Biscolla
authors.forename: Elza Setsuko
authors.initials: ES
authors.lastname: Ikejiri
authors.forename: Renata Rosa
authors.initials: RR
authors.lastname: Marchetti
authors.forename: Mario Luiz V
authors.initials: ML
authors.lastname: Castiglioni
authors.forename: Luiza Kimiko
authors.initials: LK
authors.lastname: Matsumura
authors.forename: Rui Monteiro de Barros
authors.initials: RM
authors.lastname: Maciel
authors.forename: Reinaldo Perrone
authors.initials: RP
authors.lastname: Furlanetto
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000188:drug therapy* / Q000532:radiotherapy / Q000601:surgery*; D002291:Carcinoma, Papillary; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D016651:Lithium Carbonate / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy; D013974:Thyroxine / Q000627:therapeutic use; D051598:Whole Body Imaging
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D016651:Lithium Carbonate; D013974:Thyroxine