Risk factors of skip lateral lymph node metastasis in papillary thyroid carcinoma

Single-center external validation and reconstruction of multiple predictive models for skip lateral lymph node metastasis in papillary thyroid carcinoma

Objective

The unique metastatic pattern of skip lateral lymph node metastasis (SLLNM) in PTC patients may lead to missed diagnosis of lateral cervical metastatic lymph nodes. Therefore, many different SLLNM prediction models were constructed. In this study, partially eligible models (Hu 2020, Wang 2020, and Zhao 2023 nomograms) were selected for external validation, and then new variables were incorporated for model reconstruction to extend clinical applicability.

Methods

576 PTC patients from our center were selected to evaluate the performance of the three nomograms using the receiver operating characteristic curve (ROC), calibration curves, and decision curve analyses (DCA). Three new variables were added to calibrate the model, including assessment of LN status on ultrasound (US-SLLNM), the distance from the tumor to the capsule (Capsular distance), and the number of central lymph node dissections (CLND number). Univariate and multivariate logistic regression analyses were used to screen independent predictors to reconstruct the model, and 1000 Bootstrap internal validations were performed.

Results

SLLNM were present in 69/576 patients (12.0%). In external validation, the area under the ROC curves (AUCs) for Hu 2020, Wang 2020, and Zhao 2023 nomograms were 0.695 (95% CI:0.633-0.766), 0.792 (95% CI=0.73-0.845), and 0.769 (95% CI:0.713-0.824), respectively. The calibration curves for the three models were overall poorly fitted; DCA showed some net clinical benefit. Model differentiation and net clinical benefit improved by adding three new variables. Based on multivariate analysis, female, age, and maximum tumor diameter ≤ 10 mm, located at the upper pole, Capsular distance < 0mm, US-SLLNM, CLND number ≤ 5 were identified as independent predictors of SLLNM and were used to construct the new model. After 1000 Bootstrap internal validations, the mean AUC of the model was 0.870 (95% CI:0.839-0.901), the calibration curve was close to the ideal curve, and the net clinical benefit was significant.

Conclusion

Overall, these nomograms were well differentiated and provided some net clinical benefit, but with varying degrees of underestimation or overestimation of the actual risk and high false-negative rates. New dynamic nomogram was constructed based on the addition of new variables and larger samples, showing better performance.

Risk factors for skip metastasis in patients with papillary thyroid microcarcinoma

BACKGROUND

Lymph node metastasis (LNM) is prevalent in papillary thyroid microcarcinoma (PTMC) and is essential when determining tumor stage and prognosis. Positive lateral LNM with negative central LNM is defined as skip metastasis. Thyroid carcinoma's risk factors for skip metastasis remain controversial, especially in PTMC. This study aimed to determine the clinical features as well as the risk factors of skip metastasis among patients with PTMC.

METHODS

We conducted retrospective research among patients with PTMC who were subjected to treatment at our Hospital between January 2018 and December 2019 by reviewing their medical records. A database containing demographic characteristics, ultrasonography features, blood test outcomes, operation information, pathology details, and follow-up information was constructed. The link between skip metastasis and clinicopathological features of PTMC was evaluated using univariate as well as multivariate analyses.

RESULTS

Overall, 293 patients diagnosed with PTMC and lateral LNM were included. There were 91 men (31.1%) and 202 women (68.9%). The median age was 38 (31-47) years. Fifty patients were diagnosed with skip metastases. Levels III and II + III were the most prevalent in single-level and two-level metastasis, correspondingly. Univariate and multivariate analyses detected two independent factors linked to skip metastasis in PTMC: female sex (odds ratio = 2.609, 95% confidence interval (CI): 1.135-6.000; p = 0.024) and location of the tumor (upper portion) (odds ratio = 2.959, 95% CI: 1.552-5.639; p = 0.001).

CONCLUSIONS

Skip metastasis is prevalent in thyroid carcinoma. Female sex and tumor location (upper portion) are independently linked to skip metastasis in PTMC. Patients who have these two risk factors should undergo a meticulous preoperative and intraoperative evaluation of lymph node status.

Risk factors for level V metastasis in patients with N1b papillary thyroid cancer

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer, and its incidence has increased. Lateral lymph node metastasis (LLNM) implies a worse prognosis than central lymph node metastasis, with a higher recurrence rate and decreased disease-free survival. The 2015 American Thyroid Association guidelines recommend compartmental node dissection in patients with LLNM to reduce the risk of recurrence and mortality. The purpose of this study was to identify the risk factors for level V lymph node (LN) metastasis in patients with N1b papillary thyroid cancer (PTC).

METHODS

A total of 110 consecutive patients who underwent total thyroidectomy with lateral neck dissection for PTC between April 2016 and April 2022 were retrospectively enrolled. Based on level V metastasis, 94 patients were divided into two groups, and their clinicopathological characteristics were compared. Univariable analysis were used to assess the factors associated with level V metastasis. Spearman correlation analysis were used to assess the correlation between tumors and LN. The receiver operating characteristic (ROC) curve was used to determine the optimal cutoff value for the number of metastatic LNs at each level for level V metastasis.

RESULTS

The number of metastatic LNs and lymph node ratio (LNR) in level II were significantly associated with level V metastasis (P = 0.011 and 0.001, respectively). The number of metastatic LNs in level II and those in the total number of levels correlated with the number of metastatic LNs in level V (rho = 0.331, 0.325, and P = 0.001, 0.001, respectively). The cutoff value for the number of metastatic LNs in level II was defined as 2.5 (area under the curve = 0.757, sensitivity = 50%, specificity = 82.5%, 95% confidence interval [CI] 0.626-0.889, P = 0.002). Simultaneous 3-level metastasis (level II, III, and IV) and 3-level with ≥ 2.5 metastatic LNs in level II were significantly associated with level V metastasis (P = 0.003 and 0.002).

CONCLUSIONS

The number of metastatic LNs and LNR in level II, simultaneous 3-level metastasis (level II, III, and IV), and 3-level with ≥ 2.5 metastatic LNs in level II were significantly associated with level V metastasis. (P = 0.011, 0.001, 0.003, and 0.002, respectively). In the future, larger-scale multi-institutional studies were needed to find out predictors for level V metastasis.

The efficacy and safety of microwave ablation versus conventional open surgery for the treatment of papillary thyroid microcarcinoma: a systematic review and meta-analysis

Background

Microwave ablation (MWA) technology has been applied to the treatment of papillary thyroid microcarcinoma (PTMC); however, its use as an alternative to conventional open surgery (OS) remains controversial, because it belongs to non-tumor radical treatment. Our article sought to compare the efficacy and safety of MWA and OS in the treatment of PTMC.

Methods

We searched seven databases for studies evaluating the treatment of patients with PTMC using MWA as intervention group and OS as control group, the main outcome contained intra-operative, post-operative and follow-up outcomes. Review Manager 5.4 was used to estimate the effects of the results of the included articles and Cochrane Risk of Bias 2.0 was used to assess the risk of bias. The data were pooled to calculate the mean differences (MD) with 95% confidence intervals (CIs) for the continuous data and the odds ratio (OR) with 95% CIs for the dichotomous data.

Results

A total of 13 studies, comprising 1,088 and 1,081 patients in the MWA and OS groups, respectively, were identified that compared the results of MWA to OS in the treatment of PTMC. All of the articles were at low risk of bias. There were no differences in terms of the recurrence rate (OR =0.80, 95% CI: 0.37 to 1.77; P=0.59) or lymph node metastasis (OR =0.71, 95% CI: 0.26 to 1.95; P=0.51) between the 2 groups. However, compared to the OS group, the MWA group had a shorter operation time (MD =-44.85, 95% CI: 5.73 to 20.68; P<0.00001), less intra-operative blood loss (MD =-23.37, 95% CI: -29.57 to -17.17; P<0.00001), a smaller surgical incision (MD =-47.04, 95% CI: -81.93 to -12.14; P=0.008), a shorter postoperative hospital stay (MD =-4.19, 95% CI: -5.46 to -2.92; P<0.00001), lower hospitalization expenses (MD =-85.65, 95% CI: -133.86 to -37.45; P<0.00001), and fewer complications (OR =0.23, 95% CI: 0.16 to 0.33; P<0.00001).

Conclusions

This meta-analysis suggests that MWA is better than OS at treating PTMC in terms of both intra-operative and post-operative outcomes. Due to the quality and number of the included studies, the long-term effects and suitability of MWA in the treatment of PTMC need to be further studied.

The Prognosis of Skip Metastasis in Papillary Thyroid Microcarcinoma Is Better Than That of Continuous Metastasis

CONTEXT

A few papillary thyroid microcarcinomas (PTMCs) may have skip metastasis (SLNM), but the risk factors remain controversial and the prognosis is unclear.

OBJECTIVES

To investigate the incidence, lymph node metastasis (LNM) patterns, risk factors, and prognosis of SLNM in PTMCs.

METHODS

We reviewed the medical records of PTMC patients who underwent thyroid surgery in our institution. Analyses of risk factors were performed for SLNM. Recurrence-free survival (RFS) of SLNM, central lymph node metastasis (CLNM), and continuous metastasis (CLNM and lateral lymph node metastasis [CLNM + LLNM]) were compared after propensity score matching (PSM).

RESULTS

SLNM was detected in 1.7% (50/3923) and frequently involved level III (66.7%). Compared with CLNM + LLNM, SLNM had more LNM at a single level (P < 0.01) and less LNM at 2 levels (P < 0.05). A tumor size of 0.5 to 1 cm (odds ratio [OR], 2.26; 95% CI, 1.27-4.00) and location in the upper pole (OR, 3.30; 95% CI, 2.02-5.40) were independent risk factors for SLNM. A total of 910 (23.2%) PTMCs with LNM were included in the prognostic analysis. At a median follow-up of 60 months, the RFS of SLNM did not differ from that of CLNM (P = 0.10) but was significantly higher than that of CLNM + LLNM (P < 0.01) after using PSM.

CONCLUSIONS

When the tumor size is 0.5 to 1 cm or its location is in the upper pole, we must remain vigilant to SLNM in PTMC. Because its prognosis is comparable to that of only CLNM and better than that of CLNM + LLNM, less intensive treatment should be considered.

Risk factors of skip lateral cervical lymph node metastasis in papillary thyroid carcinoma: a systematic review and meta-analysis

OBJECTIVE

To analyze and explore the risk factors of skip lateral cervical lymph node metastasis (SLLNM) in papillary thyroid carcinoma (PTC).

METHODS

PubMed, Web of Science, Embase, Cochrane, Wanfang, China National Knowledge Infrastructure, and China Science and Technology Journal databases, updated to April 4, 2021, were systematically searched for literature on the risk factors of SLLNM in PTC. The meta-analysis was completed using Stata 15.0 software after quality evaluation. The odds ratio (OR) and 95% confidence interval (CI) of each variable were calculated using fixed or random-effects models, and the publication bias was evaluated by the Egger's test.

RESULTS

A total of 28 studies with 10,682 cases were included in our meta-analysis; 1592 (14.90%) cases were positive for SLLNM. The meta-analysis showed that female sex (OR = 1.16, 95% CI = 1.02-1.31, P = 0.021), age ≥45 (OR = 1.60, 95% CI = 1.19-2.15, P = 0.002), tumor diameter ≤10 mm (OR = 2.23, 95% CI = 1.62-3.06, P < 0.001), and upper location of tumor (OR = 3.60, 95% CI = 2.65-4.89, P < 0.001) were risk factors for SLLNM in PTC patients. Hashimoto's thyroiditis (OR = 1.02, 95% CI = 0.88-1.19, P = 0.777), multifocality (OR = 0.98, 95% CI = 0.75-1.28, P = 0.873), bilateral tumors (OR = 0.92, 95% CI = 0.70-1.19, P = 0.515), extrathyroidal extensions (OR = 1.07, 95% CI = 0.83-1.39, P = 0.598), and capsular invasion (OR = 0.93, 95% CI = 0.65-1.31, P = 0.660) were not closely related to SLLNM risk.

CONCLUSION

This study confirmed significant associations between SLLNM and female sex, age ≥45, tumor diameter ≤10 mm, and upper location of the tumor.

Influence of Obesity Parameters on Different Regional Patterns of Lymph Node Metastasis in Papillary Thyroid Cancer

OBJECTIVE

Obesity increases risk of thyroid cancer. However, the association between obesity and the progression of papillary thyroid cancer (PTC) remains controversial. This retrospective study aimed to explore the relationship between obesity and regional patterns of lymph node metastasis (LNM) in PTC.

METHODS

We retrospectively reviewed data from 1015 patients with PTC. We calculated obese parameters, such as body mass index (BMI), body fat percentage (BFP), and body surface area (BSA). Logistic regression models were used to assess associations between obese parameters and the rate of lymph node metastasis (LNM), number of LNM, pattern of LNM, and lymph node ratio (LNR).

RESULTS

Higher BMI was not associated with different regional patterns of LNM in PTC. In men with PTC, high BFP was an independent predictor of total LNM, central lymph node metastasis (CLNM), total lateral lymph node metastasis (LLNM), multiple lateral lymph node metastasis, and simultaneous metastasis in lateral compartment. In addition, male patients with high BFP had higher central LNR and higher number of CLNM. For women, high BSA was an independent predictor of LLNM and level IV metastasis. Female patients with high BSA had higher number of CLNM.

CONCLUSION

BFP and BSA, possibly influenced by gender, were positively associated with the number and risk of LNM in different regions of PTC patients. However, BMI was not the predictor for aggressiveness of PTC in terms of LNM. Clinical decision-making for regional LNM in PTC patients should consider the factor of obesity.