Thyroidectomy without lateral neck dissection for papillary thyroid carcinoma with lateral neck lymph node metastases and negative intraoperative frozen section

Risk prediction for <1 cm lateral lymph node metastasis in papillary thyroid microcarcinoma

Background

Because the diameter of the suspicious lymph nodes is less than 1 cm and adjacent to important structures in the neck, the diagnosis of small LLNM is important but difficult without the help of fine needle aspiration (FNA). There are no relevant reports of risk factors that predict the risk of suspicious <1 cm LLNM.

Methods

A total of 159 PTMC patients with suspicious <1 cm LLNM were included in the study. Multivariate logistic regression analysis was used to identify ultrasound independent predictors of LLNM. A predictive model was developed according to multivariate logistic regression and evaluated by Hosmer-Lemeshow fit test.

Results

Age ≤ 38 years old, the largest PTMC was located in the upper part, and the presence of liquefaction or microcalcification in suspicious lymph nodes were independent risk factors for LLNM (univariate analysis P = 0.00, 0.00, 0.00; multivariate analysis P = 0.00, 0.02, 0.00. OR = 4.66 [CI: 1.78-12.21], 3.04 [CI: 1.24-7.46], 6.39 [CI: 1.85-22.00]). The predictive model for the diagnosis of suspicious <1 cm lymph nodes was established as: P = ex/(1 + ex). X = -1.29 + (1.11 × whether the largest tumor is located in the upper part) + (1.54 × whether the age is ≤ 38 years) + (1.85 × whether the suspicious lymph nodes have liquefaction/microcalcification). The Hosmer-Lemeshow fit test was used to test the predicted ability, and it found that the predictive model had a good fit and prediction accuracy (X2 = 6.214, P = 0.623 > 0.05). Chi squared trend analysis showed that the increase in the number of risk factors gradually increased the malignancy possibility of suspicious <1 cm lymph nodes (chi squared trend test, P = 0.00).

Conclusions

Age ≤ 38 years old, the largest PTMC located in the upper part, and the presence of liquefaction or microcalcification in suspicious lymph nodes were independent risk factors for suspicious <1 cm LLNM in PTMC patients. Our result show that it is feasible to evaluate the malignant possibility of these lymph nodes using the number of risk factors.

High rate of IIA/IIB neck groups involvement supports complete lateral neck dissection in thyroid carcinoma

Background

Although therapeutic lateral neck dissection (LND) may be indicated in thyroid carcinoma, the cervical lymph node groups IIA and IIB, according to Robbins classification, are often not removed. The aim of our study was to determine the relevance of complete comprehensive LND in thyroid carcinoma.

Methods

We conducted a retrospective study between January 2011 and August 2018 in a university teaching hospital. Histopathological analysis of LND performed during total thyroidectomy in thyroid carcinoma was reviewed according to lymph node level. To demonstrate that neck dissection of upper groups, IIA/IIB, is necessary when therapeutic LND is indicated in thyroid carcinoma, we compared histopathological involvement in complete comprehensive LND of the upper groups IIA/IIB to the lower groups III/IV/V.

Results

A total of 30 LND (24 patients) were suitable for analysis. Analysis by neck side revealed that comprehensive LND dissection samples were negative in 3 cases, and positive in 27. In those 27 positive LND, 15 demonstrated involvement of the groups IIA/IIB, and 12 were positive for involvement of the III/IV/V groups only. The combined presence of positive IIA/IIB and positive III/IV/V was observed in 15 of the 27 neck sides. There was no positive IIA/IIB without positive involvement of III/IV/V groups.

Conclusions

The high rate of positive cervical lymph nodes in the upper groups IIA/IIB supports complete comprehensive LND rather than selective III/IV/V LND in thyroid carcinoma surgery. However, impact on survival and whether postoperative radioactive iodine treatment may be modulated remain to be studied.