title: Retrospective Analysis of 255 Papillary Thyroid Carcinomas ≤2 cm: Clinicohistological Features and Prognostic Factors.
abstract: BACKGROUND
  Papillary thyroid carcinoma (PTC) is the most common thyroid cancer. The widespread use of neck ultrasound (US) and US-guided fine-needle aspiration cytology is triggering an overdiagnosis of PTC.
  
  
  OBJECTIVE
  To evaluate clinical behavior and outcomes of patients with PTCs ≤2 cm, seeking for possible prognostic factors.
  
  
  METHODS
  Clinical records of cases with histological diagnosis of PTC ≤2 cm followed at the Endocrine Department of Instituto Português de Oncologia, Lisbon between 2002 and 2006 were analyzed retrospectively.
  
  
  RESULTS
  We identified 255 PTCs, 111 were microcarcinomas. Most patients underwent near-total thyroidectomy, with lymph node dissections in 55 cases (21.6%). Radioiodine therapy was administered in 184 patients. At the last evaluation, 38 (14.9%) had evidence of disease. Two deaths were attributed to PTC. Median (±SD) follow-up was 74 (±23) months. Multivariate analysis identified vascular invasion, lymph node and systemic metastases significantly associated with recurrence/persistence of disease. In addition, lymph node involvement was significantly associated with extrathyroidal extension and angioinvasion. Median (±SD) disease-free survival (DFS) was estimated as 106 (±3) months and the 5-year DFS rate was 87.5%. Univariate Cox analysis identified some relevant parameters for DFS, but multivariate regression only identified lymph node and systemic metastases as significant independent factors. The median DFS estimated for lymph node and systemic metastases was 75 and 0 months, respectively.
  
  
  CONCLUSIONS
  In the setting of small PTCs, vascular invasion, extrathyroidal extension and lymph node and/or systemic metastases may confer worse prognosis, perhaps justifying more aggressive therapeutic and follow-up approaches in such cases.
authors.affiliation: Endocrinology Department, Instituto Português de Oncologia de Lisboa, Universidade Nova de Lisboa, Lisbon, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Marques
authors.affiliation: Endocrinology Department, Instituto Português de Oncologia de Lisboa, Universidade Nova de Lisboa, Lisbon, Portugal ; NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal.
authors.forename: Valeriano
authors.initials: V
authors.lastname: Leite
authors.affiliation: Endocrinology Department, Instituto Português de Oncologia de Lisboa, Universidade Nova de Lisboa, Lisbon, Portugal ; NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Bugalho
keywords: Microcarcinoma; Papillary thyroid carcinoma; Thyroid cancer