title: "Clinicopathological features and treatment outcomes of differentiated thyroid cancer in Saudi children and adults".
abstract: BACKGROUND
  Age is an important prognostic factor in differentiated thyroid cancer (DTC). Our aim was to evaluate differences in clinicopathological features and treatment outcomes among children and adult patients with DTC.
  
  
  METHODS
  We studied 27 children (below 18 years) with DTC treated during the period 2000-2012 and were compared with (a) 78 adults aged 19-25 years and (b) 52 adults aged 26-30 years treated during the same period in terms of their clinicopathological features and long term treatment outcomes. Locoregional recurrence (LRR), locoregional control (LRC), distant metastasis (DM), distant metastasis control (DMC), disease free survival (DFS) and overall survival (OS) rates were evaluated.
  
  
  RESULTS
  Mean age of children was 13.5 years (range: 5-18), while mean age of adults was 24.6 years (range: 19-30). In children, female: male ratio was 2.85:1, and in adults female: male ratio was 7.1:1 (P = 0.041). No significant difference in tumor size was seen between the two groups (P = 0.653). According to American Thyroid Association (ATA) risk stratification classification, the children (85.2 %) were found to have at high risk as compared to adults P = 0.001. Post-thyroidectomy complications and RAI induced toxicities were observed more in children than adults (P = 0.043 and P = 0.041 respectively). LRR occurred in 6 (22.2 %), 9 (11.5 %) and 3 (5.8 %) in age groups of <18 years, 19-25 years and 26-30 years respectively (P = 0.032); while DM was seen in 10 (37.0 %), 9 (10.3 %) and 5 (9.6 %) in age groups of <18 years, 19-25 years and 26-30 years respectively (P = 0.002). Ten year DFS rates were 67.3 % in age group below 18 years, 82.4 % in age group of 19-25 years and 90.1 % in age group of 26-30 years (P = 0.021).
  
  
  CONCLUSIONS
  At the time of diagnosis, children with DTC were found to have more aggressive clinicopathological characteristics. Comparatively lower LRC, DMC and DFS rates in children warrants further multi-institutional studies.
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, King Fahad Medical City, Riyadh, Saudi Arabia. drmutahirtonio@hotmail.com.
authors.forename: Mutahir A
authors.initials: MA
authors.lastname: Tunio
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: 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. yasserbayoumi777@yahoo.com.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Bayoumi
authors.affiliation: Radiation Oncology, King Fahad Medical City, Riyadh, Saudi Arabia. kriaz@kfmc.med.sa.
authors.forename: Khalid
authors.initials: K
authors.lastname: Riaz
authors.affiliation: Histopathology, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, 59046, Saudi Arabia. walshakweer@kfmc.med.sa.
authors.forename: Wafa
authors.initials: W
authors.lastname: AlShakweer
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D012189:Retrospective Studies; D012529:Saudi Arabia / Q000453:epidemiology; D015996:Survival Rate / Q000639:trends; D013964:Thyroid Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult