Significance of Size of Lymph Node Metastasis on Postsurgical Stimulated Thyroglobulin Levels After Prophylactic Unilateral Central Neck Dissection in Papillary Thyroid Carcinoma

Abstract

BackgroundThe prognostic significance of size of central lymph node metastasis (CLNM) in papillary thyroid carcinoma (PTC) remains unknown. Because postsurgical detectable stimulated thyroglobulin (DsTg) after radioiodine ablation may imply persistent or recurrent disease, we evaluated the association between size of CLNM and rate of DsTg in patients with PTC who underwent unilateral prophylactic central neck dissection.MethodsTo be eligible for analysis, the prophylactic central neck dissection specimen with <3 central lymph nodes (CLNs) or size of CLNM ≥1 cm as measured under the microscope was excluded. Of 132 specimens, 89 (67.4 %) were eligible. Forty patients (44.9 %) had no metastasis or pN0, 20 (22.5 %) had micrometastasis (<2 mm) or pN1mic and 29 (32.6 %) had macrometastasis (≥2 mm) or pN1mac. Postablation sTg level was measured 9 months after surgery. A multivariable analysis was conducted to identify independent factors for postablation DsTg.ResultsLarger-sized CLNM correlated significantly with younger age (p = 0.028), greater number of CLN retrieved (p = 0.016), greater number of metastatic CLN excised (p < 0.001), higher metastatic CLN ratio (p = 0.006) and postablation sTg level (p = 0.012). In the multivariable analysis, after adjusting for tumor size and metastatic CLN ratio, size of CLNM was an independent predictor of postablation DsTg (odds ratio 1.56, 95 % confidence interval 1.09–2.24, p = 0.015). Relative to pN0, the odds ratios for postablation DsTg in pN1mic and pN1mac were 2.53 (95 % confidence interval 0.35–19.00, p = 0.351) and 5.81 (95 % confidence interval 1.22–27.70, p = 0.027), respectively.ConclusionsSize of CLNM was an independent factor for DsTg 9 months after surgery. Patients with pN1mac were almost 6 times more likely to have postablation DsTg than those with pN0 or pN1mic.

Does Preoperative Neutrophil Lymphocyte Ratio Predict Risk of Recurrence and Occult Central Nodal Metastasis in Papillary Thyroid Carcinoma?

“…This was consistent to our previous analysis which found that tumor size was a risk factor for having detectable post-ablative stimulated Tg (a surrogate for persistent / recurrent disease) in cN0 PTC. 19 A recent study has also reported similar findings with tumor size (OR=1.93) and extrathyroidal extension (OR=12.47) as risk factors for LRR in cN0 PTC. 19 Interestingly, this study also found adding pCND reduced LRR (OR=0.21, 95%CI=0.11 -0.41, p<0.001).…”

The stratification of patient risk depending on the size and ratio of metastatic lymph nodes in papillary thyroid carcinoma

“…The central LNR is an independent factor related to the recurrence of PTC, and the macrometastasis of a CLN is clinically meaningful as an independent variable during the follow-up after surgery [19, 20]. However, analyses that have included both of central and lateral LN metastases are scarce.…”

A Systematic Review and Meta-Analysis of Prophylactic Central Neck Dissection on Short-Term Locoregional Recurrence in Papillary Thyroid Carcinoma After Total Thyroidectomy

“…However, it was interesting to note the incidence of central LNM varied widely from 23.5% to 82.4% between studies. Perhaps, this was also a reflection of the quality of preoperative USG assessment and might also have been a result of differences in the extent of the pCND and quality of the histological examination between studies (5,30,31). Also similar to previous meta-analyses,(9-11) we found the temporary hypocalcemia to be significantly higher in group A than B (26.0% vs. 10.8%, respectively; OR=2.56;95%CI=2.04 -3.21).…”

“…There is little evidence to suggest that patients with cN0 undergoing a total thyroidectomy (TT) and pCND (TT+pCND) would reduce risk of future LRR when compared to TT alone. Although the incidence of occult or microscopic LNM in patients with cN0 is relatively common, it is unclear whether removing these occult or microscopic LNM at the time of primary operation could prevent LRR (5,6). Analysis of short-term surrogates for recurrence (such as post-surgical thyroglobulin level) would suggest that pCND may improve short-term outcomes but this has not been fully resolved (4,7,8).…”