Papillary thyroid microcarcinoma: a study of 535 cases observed in a 50-year period.
BACKGROUND
The study aims were to characterize patients with papillary thyroid microcarcinoma and to provide data on outcome after surgical therapy.


METHODS
Five hundred thirty-five patients with papillary microcarcinoma had initial treatment at Mayo Clinic from 1940 to 1989. Follow-up extended to 48 years. Median follow-up time for 400 survivors was 16 years. Recurrence and mortality details were derived from a computerized cancer database.


RESULTS
Median tumor size was 8 mm. Ninety-nine percent of tumors were histologic grade 1; 98% were not locally invasive. Thirty-two percent of patients had nodal metastases at examination. TNM stages were I in 485 patients (91%), III in 49 patients (9%), and IV in one patient (0.2%). Ninety-one percent of patients underwent bilateral lobar resection. Tumor resection was incomplete in three cases (0.6%). Radioiodine remnant ablation was performed in 55 patients (10%). All-causes survival did not differ from expected; two patients (0.4%) died of papillary microcarcinoma. Twenty-year tumor recurrence rate was 6%. Higher recurrence rates were seen either with node-positive patients (p < 0.0001) or after unilateral lobectomy (p < 0.0001). Recurrence rates did not appear to be significantly altered by total thyroidectomy (p = 0.44) or radioiodine remnant ablation in node-positive patients (p = 0.99).


CONCLUSIONS
These results reaffirm that papillary microcarcinoma has an excellent prognosis if managed initially by bilateral lobar resection. Routine radioiodine remnant ablation is not indicated.
Hay
I D
ID
Department of Surgery, Mayo Clinic, Rochester, MN 55905.
Grant
C S
CS
van Heerden
J A
JA
Goellner
J R
JR
Ebersold
J R
JR
Bergstralh
E J
EJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D002291:Carcinoma, Papillary / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D002648:Child; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008197:Lymph Node Excision; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D016019:Survival Analysis; D013961:Thyroid Gland / Q000473:pathology; D013964:Thyroid Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome
D007457:Iodine Radioisotopes