title: Impact of histopathology of non-neoplastic thyroid tissue on ablation outcome in patients with papillary thyroid cancer.
abstract: OBJECTIVE
  To assess the impact of histopathology of non-neoplastic thyroid tissue on ablation outcome in patients with papillary thyroid cancer (PTC).
  
  
  METHODS
  The study included 124 patients referred for I-131 ablation therapy after total thyroidectomy for unifocal nonmetastatic PTC. All patients received 100 mCi of I-131 ablation dose. Follow-up whole body scan (WBS) and estimation of serum thyroglobulin level were carried out 6-9 months after ablation therapy and results were divided into complete or incomplete ablation.
  
  
  RESULTS
  Incomplete ablation was found in 66.6% (12 of 18), 64% (16 of 25), 39.1% (nine of 23), 30% (six of 20), 33% (six of 18), and 20% (four of 20) in patients with PTC in a background of Hashimoto's thyroiditis, lymphocytic thyroiditis, colloid nodular goiter, nodular hyperplasia, multinodular goiter, and normal thyroid tissue, respectively. Patients with Hashimoto's thyroiditis and lymphocytic thyroiditis had statistically significant higher failure rate to achieve complete ablation compared with other groups. This significant difference was lacking between different nonautoimmune histopathologies and normal thyroid tissue. For patients with thyroid disorders of autoimmune origin (Hashimoto's thyroiditis and lymphocytic thyroiditis), incomplete ablation was found in 65.1% (28 of 43) versus 34.4% (21 of 61) for all other nonautoimmune histopathologies collectively; the difference was statistically significant.
  
  
  CONCLUSIONS
  Histopathology of non-neoplastic thyroid tissue has a significant impact on ablation outcome in patients with PTC. Patients with a histopathology of non-neoplastic thyroid tissue of autoimmune origin have a significantly lower incidence of successful complete ablation after a single I-131 ablative dose (100 mCi) compared with those with nonautoimmune histopathology or with normal thyroid tissue.
authors.affiliation: King Abdel Aziz Hospital and Oncology Center, Jeddah, Kingdom of Saudi Arabia.
authors.forename: Shereen M
authors.initials: SM
authors.lastname: Wagieh
authors.forename: Sherif M
authors.initials: SM
authors.lastname: El-Refaei
authors.forename: Shahenda S
authors.initials: SS
authors.lastname: Salem
authors.forename: Ehab A
authors.initials: EA
authors.lastname: Al-Shiekh
authors.forename: Hasna A
authors.initials: HA
authors.lastname: Al-Ghamdy
authors.forename: Nasser R
authors.initials: NR
authors.lastname: Al-Juhani
mesh_terms: D055011:Ablation Techniques; D000328:Adult; D002277:Carcinoma; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland / Q000166:cytology* / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000601:surgery* / Q000628:therapy; D016896:Treatment Outcome; D055815:Young Adult