title: Assessment of recurrence rates in papillary thyroid microcarcinoma patients with and without histopathological risk factors after radioiodine ablation treatment.
abstract: OBJECTIVE
  We aimed to assess the recurrence rates of papillary thyroid microcarcinoma in patients with and without histopathological risk factors after radioiodine (RAI) ablation treatment.
  
  
  METHODS
  A total of 357 papillary thyroid microcarcinoma patients who were referred to Ankara University Medical School, Department of Nuclear Medicine for RAI ablation treatment after total or near-total thyroidectomy were included in the study. All patients received RAI ablation treatment 4-6 weeks after surgery. After RAI ablation, patients were monitored every 3 months within the first 6 months and then every year.
  
  
  RESULTS
  During follow-up, sixth-month iodine-131 (I-131) whole-body scans showed successful ablation in 333 (93.3%) patients. However, one (0.2%) patient had a focal lung uptake on the sixth-month I-131 whole-body scan, although the postablative scan gave no evidence of lung metastasis. Lung metastasis of this patient was treated with a second dose of RAI. The mean follow-up period was 124 (min-max: 6-216) months. No recurrence was detected in 344 (96.3%) patients during the follow-up period. However, in 13 (3.6%) patients, new recurrence or metastasis had developed. Lymph node metastasis was detected using fluorine-18 flourodeoxyglucose PET/computed tomography in four and using neck ultrasound in eight of them. The metastasis rates of patients with papillary microcarcinoma at a single focus with no thyroid capsule or lymphovascular invasion (n=268) and those of patients with thyroid capsule and/or lymphovascular invasion (n=89) were compared. Metastasis was seen in six and seven patients in those groups, respectively. The difference in metastasis rate between the two groups was statistically significant (2.2 vs. 9.2%, P=0.008).
  
  
  CONCLUSIONS
  RAI ablation is beneficial in the management of papillary thyroid microcarcinoma patients with histopathological risk factors. It also improves the sensitivity of thyroglobulin and antithyroglobulin, facilitating easier and safer follow-up.
authors.affiliation: Department of Nuclear Medicine, Ankara University Medical Faculty, Ankara, Turkey.
authors.forename: Cigdem
authors.initials: C
authors.lastname: Soydal
authors.forename: Mine
authors.initials: M
authors.lastname: Araz
authors.forename: Elgin
authors.initials: E
authors.lastname: Ozkan
authors.forename: Emrah
authors.initials: E
authors.lastname: Arslantaş
authors.forename: Ozlem N
authors.initials: ON
authors.lastname: Kucuk
authors.forename: Gulseren
authors.initials: G
authors.lastname: Aras
mesh_terms: D055011:Ablation Techniques; D000328:Adult; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography; D012008:Recurrence; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D014057:Tomography, X-Ray Computed
chemical_list: D007457:Iodine Radioisotopes