Journal List > Korean J Endocr Surg > v.16(3) > 1060171

Ghong, Park, Bang, and Kim: Can We Omit Prophylactic Central Lymph Node Dissection in Patients with Clinically LN Negative Papillary Thyroid Microcarcinoma?



Although papillary thyroid microcarcinoma (PTMC) has very excellent prognosis, lymph node metastases are found frequently. This study identifies the risk factors of clinically negative cervical lymph node metastasis (cN0) and investigates the need for central lymph node dissection in cN0 PTMC.


From Jan. 1st 2007 to Dec. 30th 2013, 1593 patients received surgery for papillary thyroid carcinoma. Seven hundred and eleven patients were diagnosed with cN0 PTMCs. They all received thyroidectomy (total thyroidectomy or lobectomy) with prophylactic central neck dissection. We reviewed the medical records and analyzed the risk factors affecting central lymph node metastasis (CLNM).


Of 711 PTMCs patients without clinical lymph node metastasis, 170 (23.9%) patients had CLNM. CLNM was frequent in males than females (P<0.001). The larger the primary tumor, the higher the risk of CLNM (P<0.001). Extrathyroidal extension was an independent risk factor of CLNM (P<0.001). Recurrence rates in the CLNM negative group was 1.3%, and in the CLNM positive group 2.4%. The CLNM positive group recurred at a slightly higher rate, but not statistically significantly (P=0.329). Five year disease free survival in the CLNM negative was 96.8%, and in the positive group 94.1%, not a statistically significant (P=0.630).


In this study, male gender, the size of primary tumor, and Extrathyroidal extension were the risk factors of occult LNM but occult LNM in PTMC was not associated with recurrence rate or five-year disease free survivals. Therefore, we can omit prophylactic central lymph node dissection in patient with cN0 PTMC.


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Fig. 1.
Ultrasound images of central lymph node metastasis. (A) LNM with a loss of normal hilar echogenicity; (B) LNM with long diameter (>5 mm) and increased echogenicity; (C) LNM with round shape; (D) LNM with extracapsular metastasis. LNM = lymph node metastasis.
Fig. 2.
Recurrence-free survival curve. 5-year disease free survival in CLNM negative and positive group were 96.8% and 94.1%. It was not different statistically (P=0.630). CLNM = central lymph node metastasis.
Table 1.
Characteristics of patients and tumors
Patients characteristics n=711 (%)
 Age Mean±SD (years) 49.03±11.57
  <45 250 (35.2)
  ≥45 461 (64.8)
  Male 128 (18.0)
  Female 583 (82.0)
Tumor characteristics  
 Tumor size (mean, mm) 5.59 (±1.93)
  Present 220 (30.9)
  Absent 491 (69.1)
  Present 309 (43.5)
  Absent 402 (56.5)
Lymph node status  
 Extracted LN (mean, n) 2.45 (±3.62)
  Present 170 (23.9)
  Absent 541 (76.1)
 CLNM (mean, n) 1.97 (±1.54)
 CLNM size (mean, max, mm) 2.31 (±1.03)
Postoperative voice change and hypoparathyroidism
 Voice change (n, %) 92 (13)
 Vocal cord palsy (n, %) 12 (1.7)
 Transient hypocalcemia (n, %) 149 (27)
 Permanent hypocalcemia (n, %) 29 (5.3)

SD = standard deviation; ETE = Extrathyroidal extension; LN = lymph node; CLNM = central lymph node metastasis.

Table 2.
Multivariate analysis of risk factors for clinically negative central lymph node metastasis
  OR P value 95% CI
Age 0.997 0.005 0.962∼0.993
Sex Tumor size 0.294 1.160 0.000 0.005 0.193∼0.450 1.045∼1.287
ETE 2.068 0.000 1.405∼3.043

ETE = extra thyroidal exte nsion; OR = odds ratio; CI = confidence interval.

Table 3.
Correlation of clinical and histological features with central neck metastasis
  CLNM (−) (n=541) CLNM (+) (n=170) P value
Patient characteristics      
 Age (mean) 49.72±11.55 46.81±11.41 0.004
 Age (<45 years:≥45 years, %) 33.8:66.2 39.4:60.6 0.183
 Sex (F:M%) 86.7:13.3 67.1:32.9 <0.001
Tumor characteristics      
 Tumor size (mean, mm) 5.42±1.97 6.12±1.66 <0.001
 Multi-focality (positive, n, %) 160 (29.6) 60 (35.3) 0.159
 Bilaterality (positive, n, %) 130 (24.0) 31 (18.2) 0.115
 Tumor number (n) 1.47±0.90 1.64±1.16 0.072
 ETE (positive, n, %) 209 (38.6) 100 (58.8) <0.001
Recurrence (−:+%) 98.7:1.3 97.6:2.4 0.329

CLNM = central lymph node metastasis; ETE = Extrathyroidal extension.

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