title: Determination of the optimal time interval for repeat evaluation after a benign thyroid nodule aspiration.
abstract: BACKGROUND
  The optimal timing for repeat evaluation of a cytologically benign thyroid nodule greater than 1 cm is uncertain. Arguably, the most important determinant is the disease-specific mortality resulting from an undetected thyroid cancer. Presently there exist no data that evaluate this important end point.
  
  
  METHODS
  We studied the long-term status of all patients evaluated in our thyroid nodule clinic between 1995 and 2003 with initially benign fine-needle aspiration (FNA) cytology. The follow-up interval was defined from the time of the initial benign FNA to any one of the following factors: thyroidectomy, death, or the most recent clinic visit documented anywhere in our health care system. We sought to determine the optimal timing for repeat assessment based on the identification of falsely benign malignancy and, most important, disease-related mortality due to a missed diagnosis.
  
  
  RESULTS
  One thousand three hundred sixty-nine patients with 2010 cytologically benign nodules were followed up for an average of 8.5 years (range 0.25-18 y). Thirty deaths were documented, although zero were attributed to thyroid cancer. Eighteen false-negative thyroid malignancies were identified and removed at a mean 4.5 years (range 0.3-10 y) after the initial benign aspiration. None had distant metastasis, and all are alive presently at an average of 11 years after the initial falsely benign FNA. Separate analysis demonstrates that patients with initially benign nodules who subsequently sought thyroidectomy for compressive symptoms did so an average of 4.5 years later.
  
  
  CONCLUSIONS
  An initially benign FNA confers negligable mortality risk during long-term follow-up despite a low risk of identifying several such nodules as thyroid cancer. Because such malignancies appear adequately treated despite detection at a mean 4.5 years after falsely benign cytology, these data support a recommendation for repeat thyroid nodule evaluation 2-4 years after the initial benign FNA.
authors.affiliation: Thyroid Section (E.N., N.K., L.K.A., E.M., E.K.A.), Division of Endocrinology, Hypertension, and Diabetes, Department of Medicine, and the Department of Pathology (E.S.C.), The Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Eric
authors.initials: E
authors.lastname: Nou
authors.forename: Norra
authors.initials: N
authors.lastname: Kwong
authors.forename: Lukas K
authors.initials: LK
authors.lastname: Alexander
authors.forename: Edmund S
authors.initials: ES
authors.lastname: Cibas
authors.forename: Ellen
authors.initials: E
authors.lastname: Marqusee
authors.forename: Erik K
authors.initials: EK
authors.lastname: Alexander
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D005188:False Negative Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000473:pathology*; D016606:Thyroid Nodule / Q000473:pathology*; D013997:Time Factors