Papillary thyroid microcarcinoma: a study of 900 cases observed in a 60-year period.
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.
Hay
Ian D
ID
Division of Endocrinology and Internal Medicine, Mayo Clinic and College of Medicine, Rochester, Minn, USA. hay.ian@mayo.edu
Hutchinson
Maeve E
ME
Gonzalez-Losada
Tomas
T
McIver
Bryan
B
Reinalda
Megan E
ME
Grant
Clive S
CS
Thompson
Geoffrey B
GB
Sebo
Thomas J
TJ
Goellner
John R
JR
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