title: Histological subtype is the most important determinant of survival in metastatic papillary thyroid cancer.
abstract: BACKGROUND
  Papillary thyroid cancer (PTC) comprises the commonest type of thyroid cancer and carries the highest rate of survival. However, when metastatic disease occurs, survival is significantly affected.
  
  
  METHODS
  We aimed to identify prognostic histopathological and clinical factors that modify survival in metastatic PTC. All cases of metastatic PTC treated at our department in the last 20 years were reviewed and analyzed.
  
  
  RESULTS
  Histological subtype was the most important determinant of survival, as classic PTC demonstrated clearly improved survival compared to follicular subtype of PTC and other less frequently seen histological subtypes. The instant risk of death for the other histological subtypes was 4.56 times higher than the risk for the classic papillary type. Overall, a 10-year survival of 76.6% in our patients was seen.
  
  
  CONCLUSIONS
  Patients with aggressive variants of PTC are more at risk for the development of metastatic disease. In these patients, established treatment modalities (surgery, radioiodine therapy) should be offered promptly, as well as close follow-up.
authors.affiliation: Department of Endocrinology & Endocrine Oncology, Theagenio Cancer Hospital, Thessaloniki 54007, Greece.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Chrisoulidou
authors.affiliation: Department of Endocrinology & Endocrine Oncology, Theagenio Cancer Hospital, Thessaloniki 54007, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Boudina
authors.affiliation: Department of Nuclear Medicine, Theagenio Cancer Hospital, Thessaloniki 54007, Greece.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Tzemailas
authors.affiliation: Department of Endocrinology & Endocrine Oncology, Theagenio Cancer Hospital, Thessaloniki 54007, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Doumala
authors.affiliation: Department of Endocrinology & Endocrine Oncology, Theagenio Cancer Hospital, Thessaloniki 54007, Greece.
authors.forename: Pashalia K
authors.initials: PK
authors.lastname: Iliadou
authors.affiliation: Department of Pathology, Theagenio Cancer Hospital, Thessaloniki, Greece.
authors.forename: Frideriki
authors.initials: F
authors.lastname: Patakiouta
authors.affiliation: Department of Endocrinology & Endocrine Oncology, Theagenio Cancer Hospital, Thessaloniki 54007, Greece.
authors.forename: Kalliopi
authors.initials: K
authors.lastname: Pazaitou-Panayiotou