PurposeWe evaluated the capability of the neutrophil to lymphocyte ratio (NLR) as a diagnostic tool to discriminate between poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC) from well differentiated thyroid cancer (WDTC).MethodsThe NLR of 3,870 patients with benign and malignant thyroid tumors were analyzed. There were 436 benign, 3,364 papillary, 15 medullary, 34 follicular or hurthle type, 14 PDTC, and 7 ATC type neoplasms. Patients were divided into two groups: a high NLR group and a low NLR group.ResultsThe NLR of all 3,870 patients was a normal distribution, and the median value was 1.57. Advanced stage cancer, such as T3 or T4 was high (30.4% vs. 26.5%, P = 0.027), and cancer-specific deaths were also high (1.2% vs. 0.4%, P = 0.018) in the high NLR group. The proportion of PDTC (0.6% vs. 0.1%) and ATC (0.3% vs. 0.1%) was higher in the high NLR group. The NLR can discriminate between PTC, PDTC, and ATC (P = 0.035, P = 0.002, and P = 0.025, respectively), and the cutoff value was 3.8 between PDTC versus ATC. None of the NLR of PDTC exceeded the cutoff value of 3.8.ConclusionNLR can play a relevant role as a discriminating tool and may be considered as a new diagnostic criterion in discriminating as well as in selecting therapeutic approaches to these aggressive forms of thyroid cancer.

Skip lymph node (LN) metastases in papillary thyroid carcinoma (PTC) belong to N1b classification in the absence of central neck LN involvement. This study aimed to evaluate the predictive factors of skip metastases and their impact on recurrence in PTC patients with pN1b. A total of 334 PTC patients who underwent total thyroidectomy with LN dissection (central and lateral neck compartment) followed by radioactive iodine ablation were included. Patients with skip metastases tended to have a small primary tumor (≤1 cm) and single lateral neck level involvement. Tumor size ≤ 1 cm was an important predictive factor for skip metastases. Univariate analysis for recurrence showed that patients with a central LN ratio > 0.68, lateral LN ratio > 0.21, and stimulated thyroglobulin (Tg) levels > 7.3 ng/mL had shorter RFS (recurrence-free survival). The stimulated Tg level was associated with shorter RFS on multivariate analysis (>7.3 vs. ≤7.3 ng/mL; hazard ratio, 4.226; 95% confidence interval, 2.226−8.022; p < 0.001). Although patients with skip metastases tended to have a small primary tumor and lower burden of lateral neck LN involvement, there was no association between skip metastases and RFS in PTC with pN1b. Stimulated Tg level was a strong predictor of recurrence.

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