title: Papillary thyroid microcarcinoma: a study of 900 cases observed in a 60-year period.
abstract: BACKGROUND
  The study aims were to characterize patients with papillary thyroid microcarcinoma (PTM) and to describe post-surgical outcome.
  
  
  METHODS
  Nine hundred PTM patients had initial treatment at Mayo Clinic during 1945-2004. Mean follow-up was 17.2 years. Recurrence and mortality details were derived from a computerized database.
  
  
  RESULTS
  Median tumor size was 7 mm; 98% were intrathyroidal. 273 patients (30%) had neck nodal involvement; 3 (0.3%) had distant metastases at diagnosis. Seven-hundred and sixty-five (85%) underwent bilateral lobar resection (BLR; total-, near-total, or bilateral subtotal thyroidectomy). Regional nodes were removed by either "node picking" (27%) or compartmental dissection (23%). Tumor resection was incomplete in 5 (0.6%). Radioiodine remnant ablation (RRA) was performed in 155 (17%). Overall survival did not differ from expected for an age and gender matched control group (P = .96); 3 patients (0.3%) died of PTM. None of the 892 patients with initial complete tumor resection developed metastatic spread during 20 postoperative years. Twenty-year and 40-year tumor recurrence rates were 6% and 8%, respectively. Higher recurrence rates were seen with multifocal tumors (P = .004) and node-positive patients (P < .001). Neither more extensive surgery nor RRA reduced recurrence rates compared to unilateral lobectomy.
  
  
  CONCLUSIONS
  More than 99% of PTM patients are not at risk of distant spread or cancer mortality. RRA after BLR did not improve postoperative outcome.
authors.affiliation: Division of Endocrinology and Internal Medicine, Mayo Clinic and College of Medicine, Rochester, Minn, USA. hay.ian@mayo.edu
authors.forename: Ian D
authors.initials: ID
authors.lastname: Hay
authors.forename: Maeve E
authors.initials: ME
authors.lastname: Hutchinson
authors.forename: Tomas
authors.initials: T
authors.lastname: Gonzalez-Losada
authors.forename: Bryan
authors.initials: B
authors.lastname: McIver
authors.forename: Megan E
authors.initials: ME
authors.lastname: Reinalda
authors.forename: Clive S
authors.initials: CS
authors.lastname: Grant
authors.forename: Geoffrey B
authors.initials: GB
authors.lastname: Thompson
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Sebo
authors.forename: John R
authors.initials: JR
authors.lastname: Goellner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000401:mortality / Q000473:pathology* / Q000556:secondary*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D013965:Thyroidectomy; D016896:Treatment Outcome; D055815:Young Adult