Prognostic value of lymph node metastases of differentiated thyroid cancer (DTC) according to the local advancement and range of surgical excision

Exploration and validation of key genes associated with early lymph node metastasis in thyroid carcinoma using weighted gene co-expression network analysis and machine learning

Background

Thyroid carcinoma (THCA), the most common endocrine neoplasm, typically exhibits an indolent behavior. However, in some instances, lymph node metastasis (LNM) may occur in the early stages, with the underlying mechanisms not yet fully understood.

Materials and methods

LNM potential was defined as the tumor's capability to metastasize to lymph nodes at an early stage, even when the tumor volume is small. We performed differential expression analysis using the 'Limma' R package and conducted enrichment analyses using the Metascape tool. Co-expression networks were established using the 'WGCNA' R package, with the soft threshold power determined by the 'pickSoftThreshold' algorithm. For unsupervised clustering, we utilized the 'ConsensusCluster Plus' R package. To determine the topological features and degree centralities of each node (protein) within the Protein-Protein Interaction (PPI) network, we used the CytoNCA plugin integrated with the Cytoscape tool. Immune cell infiltration was assessed using the Immune Cell Abundance Identifier (ImmuCellAI) database. We applied the Least Absolute Shrinkage and Selection Operator (LASSO), Support Vector Machine (SVM), and Random Forest (RF) algorithms individually, with the 'glmnet,' 'e1071,' and 'randomForest' R packages, respectively. Ridge regression was performed using the 'oncoPredict' algorithm, and all the predictions were based on data from the Genomics of Drug Sensitivity in Cancer (GDSC) database. To ascertain the protein expression levels and subcellular localization of genes, we consulted the Human Protein Atlas (HPA) database. Molecular docking was carried out using the mcule 1-click Docking server online. Experimental validation of gene and protein expression levels was conducted through Real-Time Quantitative PCR (RT-qPCR) and immunohistochemistry (IHC) assays.

Results

Through WGCNA and PPI network analysis, we identified twelve hub genes as the most relevant to LNM potential from these two modules. These 12 hub genes displayed differential expression in THCA and exhibited significant correlations with the downregulation of neutrophil infiltration, as well as the upregulation of dendritic cell and macrophage infiltration, along with activation of the EMT pathway in THCA. We propose a novel molecular classification approach and provide an online web-based nomogram for evaluating the LNM potential of THCA (http://www.empowerstats.net/pmodel/?m=17617_LNM). Machine learning algorithms have identified ERBB3 as the most critical gene associated with LNM potential in THCA. ERBB3 exhibits high expression in patients with THCA who have experienced LNM or have advanced-stage disease. The differential methylation levels partially explain this differential expression of ERBB3. ROC analysis has identified ERBB3 as a diagnostic marker for THCA (AUC=0.89), THCA with high LNM potential (AUC=0.75), and lymph nodes with tumor metastasis (AUC=0.86). We have presented a comprehensive review of endocrine disruptor chemical (EDC) exposures, environmental toxins, and pharmacological agents that may potentially impact LNM potential. Molecular docking revealed a docking score of -10.1 kcal/mol for Lapatinib and ERBB3, indicating a strong binding affinity.

Conclusion

In conclusion, our study, utilizing bioinformatics analysis techniques, identified gene modules and hub genes influencing LNM potential in THCA patients. ERBB3 was identified as a key gene with therapeutic implications. We have also developed a novel molecular classification approach and a user-friendly web-based nomogram tool for assessing LNM potential. These findings pave the way for investigations into the mechanisms underlying differences in LNM potential and provide guidance for personalized clinical treatment plans.

BRAF V600E mutation in prognostication of papillary thyroid cancer (PTC) recurrence

Papillary thyroid cancer (PTC) offers excellent prognosis, however relapse risk or persistent disease is related to ~30%. Currently, attention is paid to the possibility of patient group selection of different risk of unfavorable outcome to match a particular therapeutic approach. Therefore, interest in new prognostic and predictive markers known preoperatively is observed. BRAF V600E mutation is such a marker. Many studies analyzing the prevalence of the mutation and its relationship with other clinico-pathological risk factors were reported but with controversial conclusions. The prognostic significance of BRAF mutation was confirmed by some single centre studies, a few meta-analyses and a large multicenter retrospective international study. They confirmed a correlation between the mutation and the risk of recurrence. The strongest argument against using BRAF mutation as an independent prognostic and predictive factor in PTC is its high prevalence (30-80%). At present it seems that BRAF mutation is one of the factors influencing the prognosis and it should be analyzed in correlation with other prognostic factors. The most recent ATA recommendations do not indicate a routine application of BRAF status for initial risk stratification in differentiated thyroid cancer due to a lack of evident confirmation of a direct influence of mutation on the increase in relapse risk. However, ATA demonstrates the continuous risk scale for the relapse risk assessment, considering BRAF and/or TERT status. At present, researchers are working on determining the role of BRAF mutation in patients from a low-risk group and its correlations with others molecular events. Currently, BRAF mutation cannot be used as a single, independent predictive factor. However, its usefulness in the context of other molecular and clinico-pathological risk factors cannot be excluded. They may be used to make modern prognostic scales of relapse risk and be applied to individualized diagnostic and therapeutic strategy for PTC patients.

Cervical lymph node metastasis in differentiated thyroid carcinoma: does it have an impact on disease-related morbid events?

PURPOSE

The aim of the study was to evaluate the prognostic impact of cervical lymph node (CLN) metastasis in well-differentiated thyroid cancer (WDTC).

PATIENTS AND METHODS

A cohort of 164 patients who underwent thyroidectomy for WDTC in the last 12 years was studied. Patients were classified into those with CLN metastasis (group 1) and those without (group 2), with 82 patients in each group. Morbid events (recurrence and death) and prognostic risk factors were analyzed.

RESULTS

The mean age of the whole group was 41.3±14.2 years, with 52.4% being at least 45 years old; 69.6% of the patients were female (P=0.02), with a female to male ratio of 2.3 : 1. Near-total thyroidectomy and radioactive iodine-131 therapy were performed in all 81.1% of patients in whom papillary cancer was found. Morbid events were found in 22/164 (13.4%) patients (17 recurrences and five deaths). All recurrences occurred in patients with the papillary subtype, whereas 4/5 deaths occurred in those with follicular thyroid cancer. Morbid events were found in 14/82 (17.1%) and 8/82 (9.6%) patients in group 1 and group 2, respectively (P=0.1). Comparison of morbid events between group 1 and group 2 showed statistically significant differences with respect to tumor size of 1 cm or more, multifocality, and positivity of the follow-up diagnostic tools at 6-12 months. Kaplan-Meier analysis revealed no significant difference between the two groups (P=0.4) over a mean follow-up period of 125.1±14.6 months. Multivariate Cox analysis showed that development of remote deposits, lymph node metastasis five or more nodes, extracapsular nodal invasion in at least three nodes, and positivity of the follow-up diagnostic tools at 6 months were the significant prognostic factors of morbid events.

CONCLUSION

Our study revealed the impact of CLN metastasis on the occurrence of morbid events in WDTC patients (especially in those with the papillary subtype) with node metastasis five or more, extracapsular nodal invasion in at least three nodes, and positivity of follow-up diagnostic tools at 6 months. Hence, these patients should be optimally managed and more closely monitored.

Differentiated thyroid cancer in patients over 60 years of age at presentation: a retrospective study of 438 patients

OBJECTIVES

The aim of this study is to identify the prognostic factors predicting remission and subsequent disease relapse in patients with differentiated thyroid cancer (DTC) greater than 60years of age.

MATERIALS AND METHODS

The institute thyroid cancer database had 4370 patients with DTC, of which 447 (10%) were aged>60. However, 9 patients were excluded due to follow-up less than 1year. The prognostic factors in the remaining 438 patients were studied.

RESULTS

Among the 438 patients, 311 (71%) had only loco-regional disease (M0) and 127 (29%) had distant metastases (M1) at the time of initial presentation. The host factors predictive of distant metastases at presentation were female gender, primary tumor size (>4cm), follicular histology, and extra-thyroidal extension. Among Mo patients, 195 (63%) achieved complete remission while only 12 (9%) M1 patients did so. Average number of radioactive iodine ((131)I) doses administered to achieve complete remission was 2.3 (range, 1-6) and the mean cumulative dose was 3404MBq (range, 925-46,250MBq). In multivariate logistic regression among M0 patients, follicular histology, nodal metastases, and surgical treatment lesser than total/near-total thyroidectomy and among M1 patients, site of distant metastases (skeletal and multiple sites) were independent factors predicting non-remission. Among the patients (both M0 and M1) who achieved remission, factors associated with disease recurrence were primary tumor size (>4cm), nodal metastases, pulmonary metastases, and non-remission after first dose of radioactive iodine and were associated with greater chances of disease relapse.

CONCLUSION

This study highlights that DTC in older patients behaves more aggressively than in adults age<60years, and identifies several prognostic factors for remission and subsequent relapse.

Proposed algorithm for management of patients with thyroid nodules/focal lesions, based on ultrasound (US) and fine-needle aspiration biopsy (FNAB); our own experience

Background

The standard management in patients with thyroid nodules is to assess the risk of malignancy, based on cytological examination. On the other hand, there are thyroid patterns of ultrasound (US) image, associated with an increased risk of malignancy.

The aim of our study was to create a diagnostic algorithm that would employ both data from US examination (expressed by a total score, according to our scoring system) and FNAB results, classified according to Bethesda system (The Bethesda System for Reporting Thyroid Cytopathology - TBSRTC categories).

Material and methods

100 thyroid cancer foci (94 papillary carcinomas, 4 medullary carcinomas, 2 undifferentiated carcinomas) and 100 benign focal lesions were selected during postoperative histopathological examination of thyroid glands excised during surgery from 111 patients. The corresponding US images of each lesion – performed in the course of preoperative diagnostics – were evaluated for the presence of seven (7) different features in US image, suggesting a malignant character of lesion, viz. vascularity, i.e., the increased central intranodular blood flows, microcalcifications, “taller-than-wide” orientation, solid composition, hypoechogenicity, irregular margin and either absence of peripheral halo or the presence of outer shell of uneven thickness, surrounding the lesion. The sensitivity, specificity, positive predictive values, negative predictive values and odds ratios for each US feature were calculated.

Results

In US image of the analyzed cancer foci, we obtained the following values of odds ratio for each of the above mentioned features suggesting malignancy: “taller-than-wide” orientation - odds ratio - 301.0, microcalcifications - 24.67, increased intranodular vascularity - 20.44, hypoechogenicity - 18.61, irregular margins - 7.81, absence of halo - 5.88, and solid composition - 4.16.

Taking into account our own experience and the present data, in juxtaposition with the opinions of other authors, we propose a division of US features into 3 groups of different prognostic importance, expressed by a total score calculated based on our scoring system. Accordingly, microcalcifications, “taller-than-wide” orientation, the increased intranodular vascularity, and hypoechogenicity constitute one group - each of the features in this group is awarded 1 point. In turn, the characteristics of minor prognostic importance, such as irregular margin, absence of halo, solid composition, and large size (a diameter longer than 3.0 cm) - are associated with the granting 0.5 points each. The most important prognostic features – a rapid growth (enlargement) of nodules/focal lesions and a presence of pathologically altered lymph nodes are associated with the granting 3 points for each.

Our scoring system can be applied in order to better assessment of thyroid US patterns in whole. In patients with a total score ranging from 0 < 4 points there is US pattern of a low risk of malignancy, with ≥ 4 < 7 points - intermediate risk, and in patients with a score ≥ 7 points – a high risk in question.

Conclusion

Complementary use of our scoring system and FNAB TBSRTC categories can help to make optimal clinical decisions as regards the selection of treatment strategy.

The role of prophylactic central neck dissection in differentiated thyroid carcinoma: issues and controversies

Prophylactic central neck dissection (pCND) in differentiated thyroid carcinoma (DTC) is one of the most controversial surgical subjects in recent times. To date, there is little evidence to support the practice of pCND in patients with DTC undergoing total thyroidectomy. Although the recently revised American Thyroid Association (ATA) guideline has clarified many inconsistencies regarding pCND and has recommended pCND in “high-risk” patients, many issues and controversies surrounding the subject of pCND in DTC remain. The recent literature has revealed an insignificant trend toward lower recurrence rate in patients with DTC who undergo total thyroidectomy and pCND than those who undergo total thyroidectomy alone. However, this was subjected to biases, and there are concerns whether pCND should be performed by all surgeons who manage DTC because of increased surgical morbodity. Performing a unilateral pCND may be better than a bilateral pCND given its lower surgical morbidity. Further studies in this controversial subject are much needed.