title: Clinical outcome in differentiated thyroid carcinoma and microcarcinoma.
abstract: BACKGROUND
  Due to the frequent use of neck ultrasonography, the incidence of differentiated thyroid microcarcinoma (DTMC), defined as a lesion with greatest dimension ≤1 cm, is increasing worldwide. Although DTMC generally has a lower aggressivity and a better prognosis than differentiated thyroid carcinoma (DTC), some cases of clinically aggressive DTMC were found. The aim of this study is to compare the rate of recurrence in DTMC and DTC, during a 3-year follow-up.
  
  
  METHODS
  Patients with differentiated thyroid carcinoma, who underwent total thyroidectomy and postoperative (131)I-RAI ablation, were stratified according to lesion diameter (DTC for diameter > 1 cm or DTMC ≤ 1 cm). After surgery, patients underwent a 3-year follow-up. Recurrent disease was defined on the basis of positive biochemical (Tg > 2 ng/ml under TSH-suppression or after rhTSH-stimulation) and/or imaging (US, WBS, CT, PET/CT) findings.
  
  
  RESULTS
  449 patients have been included in the final analysis. Linfoadenectomy rate and RAI ablative dose were significantly higher in DTC than in DTMC (32.7% vs. 22.4%, p = 0.018 and 112.3 ± 21 vs. 68.3 ± 24.1 mCi, p < 0.001). During the follow-up, 50 carcinoma recurrences occurred, more frequent in DTC than in DTMC (15.6% vs. 7.6%, p = 0.010). After adjustment for gender, age, rate of lymph node dissection and 131I dose of RAI treatment, the difference in the risk of recurrence was no longer significant among DTC and DTMC patients (HR: 1.585, 95% CI 0874-2877, p = 0.130).
  
  
  CONCLUSIONS
  The prediction of disease severity cannot be based exclusively on lesion diameter. A more careful therapeutic approach and follow-up should be recommended in DTMC patients.
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Lupoli
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Cacciapuoti
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Tortora
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Livia
authors.initials: L
authors.lastname: Barba
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Nunzia
authors.initials: N
authors.lastname: Verde
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Fiammetta
authors.initials: F
authors.lastname: Romano
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Vastarella
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Fonderico
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Masone
authors.affiliation: Department of Advanced Biomedical Sciences, Federico II University, Naples, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Milone
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy. Electronic address: lupoli@unina.it.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Lupoli
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Gelsy Arianna
authors.initials: GA
authors.lastname: Lupoli
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000209:etiology*; D011379:Prognosis; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D018714:Radiotherapy, Adjuvant; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy; D047368:Tumor Burden
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals
keywords: Lymphadenectomy; Recurrence; Thyroid carcinoma; Thyroidectomy