Clinical impact of microscopic extrathyroidal extension in patients with papillary thyroid microcarcinoma treated with hemithyroidectomy.
BACKGROUND
Pathologically confirmed microscopic extrathyroidal extension (ETE) is often identified after hemithyroidectomy in patients with papillary thyroid microcarcinoma (PTMC). Without the presence of microscopic ETE, these patients would be optimal candidates for hemithyroidectomy.


OBJECTIVE
The present study aimed at evaluating the clinical impact of microscopic ETE on the recurrence of PTMC treated with hemithyroidectomy.


METHODS
We compared the clinicopathological characteristics and 5-year outcomes for 262 PTMC patients without ETE and 86 with microscopic ETE who were treated with hemithyroidectomy between January 2004 and December 2010.


RESULTS
The mean tumour size was larger (0.67 vs. 0.54 cm, p < 0.001) and the proportion of tumours measuring ≥0.5 cm was higher (84.9 vs. 66.8 %, p = 0.001) in patients with microscopic ETE as compared with patients without ETE. Occult multifocal disease was more frequent in patients with microscopic ETE than in those without ETE (14.0 vs. 6.5 %, p = 0.030). However, the recurrence rate was not different between the two groups during the mean 55.8-month follow-up period. In addition, univariate and multivariate analyses revealed no meaningful association between recurrence and microscopic ETE in patients with PTMC treated with hemithyroidectomy.


CONCLUSIONS
Although microscopic ETE was associated with large tumour size and multifocal disease, its clinical impact on disease recurrence was not significant in PTMC patients treated with hemithyroidectomy. Therefore, microscopic ETE identified after hemithyroidectomy would not be an absolute indication for completion thyroidectomy in patients with PTMC.
Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University, Daegu, Korea.
D
D
Ahn
J H
JH
Sohn
J H
JH
Jeon
J Y
JY
Jeong
D000328:Adult; D002291:Carcinoma, Papillary / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D011379:Prognosis; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods*; D016896:Treatment Outcome; D047368:Tumor Burden