title: Adjuvant Radioactive iodine 131 ablation in papillary microcarcinoma of thyroid: Saudi Arabian experience [corrected].
abstract: BACKGROUND
  Papillary Microcarcinoma (PMC) of thyroid is a rare type of differentiated thyroid cancer (DTC), which according to the World Health Organization measures 1.0 cm or less. The gold standard of treatment of PMC is still controversy. Our aim was to contribute in resolving the debate on the therapeutic choices of the surgical and adjuvant I-131 (RAI) treatment in PMC.
  
  
  METHODS
  From 2000 to 2012, 326 patients were found to have PMC and were retrospectively reviewed for clinicopathological characteristics, treatment outcomes and prognostic factors.
  
  
  RESULTS
  Mean age of cohort was 42.6 years (range: 18-76) and the mean tumor size was 0.61 cm ± 0.24; lymph node involvement was seen in 12.9 % of cases. Median follow up period was 8.05 years (1.62-11.4). Total 23 all site recurrences (7.13 %) were observed; more observed in patients without I-131 ablation (p <0.0001). Ten year DFS rates were 89.6 %. Cox regression Model analysis revealed size, histopathologic variants, multifocality, extrathyroidal extension, lymphovascular space invasion, nodal status, and adjuvant RAI ablation the important prognostic factors affecting DFS.
  
  
  CONCLUSIONS
  Despite excellent DFS rates, a small proportion of patients with PMC develop recurrences after treatment. Adjuvant RAI therapy improves DFS in PMC patients with aggressive histopathologic variants, multifocality, ETE, LVSI, tumor size (> 0.5 cm) and lymph node involvement. Failure of RAI ablation to decrease risk in N1a/b supports prophylactic central neck dissection during thyroidectomy, however more trials are warranted.
  
  
  CONCLUSIONS
  Adjuvant I-131 ablation following thyroidectomy in PMC patients, particularly with poor prognostic factors improves DFS rates.
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, College of Medicine, King Saud University, Riyadh, Saudi Arabia. kalqahtani@KSU.EDU.SA.
authors.forename: Khalid Hussain
authors.initials: KH
authors.lastname: Al-Qahtani
authors.affiliation: Radiation Oncology, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, 59046, Saudi Arabia. masiri@kfmc.med.sa.
authors.forename: Mushabbab
authors.initials: M
authors.lastname: Al Asiri
authors.affiliation: Radiation Oncology, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, 59046, Saudi Arabia. drmutahirtonio@hotmail.com.
authors.forename: Mutahir A
authors.initials: MA
authors.lastname: Tunio
authors.affiliation: Endocrinology and thyroid Oncology, King Fahad Medical City, Riyadh, 59046, Saudi Arabia. njaljohani@kfmc.med.sa.
authors.forename: Naji J
authors.initials: NJ
authors.lastname: Aljohani
authors.affiliation: Radiation Oncology, NCI, Cairo University, Cairo, Egypt. y_bayoumi@yahoo.com.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Bayoumi
authors.affiliation: Histopathology, King Fahad Medical City, Riyadh, 59046, Saudi Arabia. h.fatani@kfmc.med.sa.
authors.forename: Hanadi
authors.initials: H
authors.lastname: Fatani
authors.affiliation: Radiation Oncology, King AbdulAziz University, Riyadh, 59046, Saudi Arabia. arehaman@kfmc.med.sa.
authors.forename: Abdulrehman
authors.initials: A
authors.lastname: AlHadab
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000532:radiotherapy* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D012529:Saudi Arabia / Q000453:epidemiology; D015996:Survival Rate / Q000639:trends; D013964:Thyroid Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes