Subclinical lymph node metastasis in papillary thyroid microcarcinoma: a study of 551 resections.
BACKGROUND
In clinically node-negative papillary thyroid microcarcinoma (PTMC), the frequency of subclinical lymph node metastasis (LNM) in the central cervical compartment (subclinical central LNM) has been reported to be as great as 65%. Routine prophylactic central compartment lymph node dissection (CLND) has been debated, because the risk of operative complications might outweigh its prognostic benefit. We aimed to study clinicopathologic factors associated with subclinical central LNM to be considered for determination of prophylactic CLND.


METHODS
A total of 551 patients diagnosed with clinically node-negative PTMC from 2005 to 2009 were included. All patients underwent total thyroidectomy (TT) and prophylactic CLND. Clinicopathologic risk factors of subclinical central LNM were analyzed. In addition, we investigated recurrences and postoperative complications after TT and CLND.


RESULTS
Among the 551 patients, 202 (37%) had subclinical central LNM. On univariate and multivariate analyses, male gender, tumor multifocality, and extrathyroidal extension were independently predictive of subclinical central LNM. During 3-year follow-up, there were no recurrences in the central cervical compartment. The frequency of permanent hypocalcemia and permanent vocal fold palsy were 1.1% and 1.3%, respectively.


CONCLUSIONS
Frequency of subclinical central LNM was high in PTMC. It was managed effectively with prophylactic CLND. In addition, prophylactic CLND did not cause significant permanent morbidities. We recommend that clinicopathologic features, such as male gender, tumor multifocality, and extrathyroidal extension, be considered for determination of prophylactic CLND in patients with PTMC.
So
Yoon Kyoung
YK
Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Son
Young-Ik
YI
Hong
Sang Duk
SD
Seo
Min Young
MY
Baek
Chung-Hwan
CH
Jeong
Han-Sin
HS
Chung
Man Ki
MK
D000328:Adult; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery*; D003131:Combined Modality Therapy; D018450:Disease Progression; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008197:Lymph Node Excision / Q000706:statistics & numerical data*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D011336:Probability; D012189:Retrospective Studies; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery*; D013965:Thyroidectomy
D007457:Iodine Radioisotopes