Different clonal origin of bilateral papillary thyroid carcinoma, with a review of the literature

Multifocal Papillary Thyroid Carcinomas With Discordant Molecular Drivers: Emphasizing the Morphology and Collision Tumors

Multifocal papillary thyroid carcinomas (PTCs) are common and the majority of the tumors harbor mutual BRAF p.V600E mutation. This study aimed to investigate a contemporary series of multifocal PTCs with discordant molecular drivers. Consecutive thyroidectomies diagnosed with multifocal PTCs ≥0.5 cm between 2019 and 2023 were reviewed. Immunohistochemistry (IHC) for BRAF VE1 was performed for all tumors. Cases with discordant BRAF IHC results or morphologic discrepancy were identified, and BRAF IHC-negative tumors were subjected to RAS Q61R IHC and/or targeted RNA next-generation sequencing. A total of 770 patients with a main PTC ≥0.5 cm were identified; 255 (33.1%) had multifocal disease, and 142 (18.4%) had at least another PTC ≥0.5 cm. Among them, 13 cases (9.2%, 13/142) had discordant molecular drivers. Twelve cases had one or more BRAF -positive PTCs accompanied by a BRAF -negative PTC (3 with CCDC6::RET fusion, 1 with NCOA4::RET fusion, 1 with ACBD5::RET fusion, 2 with ETV6::NTRK3 fusion, 1 with TG::FGFR1 fusion, 1 with LMTK2::BRAF fusion, 1 with AGK::BRAF fusion and RAS p.Q61R mutation, 1 with RAS p.Q61R mutation, and 1 without detectable molecular drivers). The last case had tumors with discordant fusion drivers ( VIM::NTRK3 and TNS1::BRAF ). Most cases showed tumors that were morphologically distinct (92.3%, 12/13) and occurred in the contralateral lobes (76.9%, 10/13). Notably, we identified 4 cases (30.8%) that presented as collision tumors and 6 cases (46.2%) that showed lymph node metastases, including 2 with simultaneous involvement by tumors with discordant molecular drivers, as novel findings. In summary, a subset (9.2%) of multifocal PTCs had discordant molecular drivers and 84.6% of them were a combination of BRAF -positive and kinase gene fusion-associated PTCs, most with distinct morphologies. Almost half of the cases had nodal metastasis and a third of them showed simultaneous involvement by tumors with discordant molecular drivers. The results highlight the clinical importance of identifying such cases, given the potentially different treatments.

Analysis of the clonal origin and differences in the biological behavior of multifocal papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) exhibits a trend of multifocal growth. However, the clonal origin of multiple cancer foci in the thyroid gland remains an issue of ongoing debate. In order to investigate the clonal origin and biological behavior differences of multifocal PTC (MPTC) from a unique perspective, a combination of dual gene and dual protein detection methods was used. The present study included 52 patients with MPTC. Immunohistochemical staining was used to assess the expression of v-raf murine sarcoma viral oncogene homolog B1 (BRAF) and telomerase reverse transcriptase (TERT) proteins, while quantitative PCR and Sanger sequencing were used to identify BRAF and TERT gene mutations. Based on the results, MPTC cases were classified into two clonal origins, namely intraglandular metastatic (71.2%) and independent multicentric origin (28.8%). BRAF protein expression and BRAF gene mutation were significantly higher in the intraglandular metastasis group than in the multicentric cancer group. However, no significant differences in TERT protein expression and TERT gene mutation were observed between the two groups. Sex, central lymph node metastasis rate, Hashimoto's thyroiditis and tumor distribution laterality were not found to differ significantly between the two groups. However, significant differences were detected in age at initial diagnosis, lateral cervical lymph node metastasis rate, tumor capsule invasion rate and maximum tumor diameter. The study found that MPTC predominantly occurs due to intraglandular metastasis, which is associated with stronger tumor invasiveness than cancer foci with multiple independent origins, as it is more likely to exhibit pathogenic gene mutations and abnormal protein expression, cervical lymph node metastasis and capsule invasion. Therefore, it is recommended that the surgical approaches and follow-up strategies for intraglandular metastatic MPTC should be aggressive and individualized.

Standardized Ultrasound Evaluation for Active Surveillance of Low-Risk Thyroid Microcarcinoma in Adults: 2024 Korean Society of Thyroid Radiology Consensus Statement

Active surveillance (AS) has been widely adopted as an alternative to immediate surgery owing to the indolent nature and favorable outcomes of papillary thyroid microcarcinoma (PTMC). AS is generally recommended for tumors measuring ≤1 cm without aggressive cytological subtypes, risk of gross extrathyroidal extension (ETE), lymph node metastasis (LNM), or distant metastasis. AS requires careful patient selection based on various patient and tumor characteristics, and ultrasound (US) findings. Moreover, during AS, regular US is performed to monitor any signs of tumor progression, including tumor growth, new US features of potential gross ETE, and LNM. Therefore, appropriate imaging-based assessment plays a crucial role in determining whether AS or surgery should be pursued. However, detailed recommendations concerning US evaluation are currently insufficient, necessitating the formulation of this guideline. The Korean Society of Thyroid Radiology has developed a consensus statement for low-risk PTMC, covering US assessment methods when considering AS as a management option and conducting follow-up imaging tests during AS. This guideline aims to provide optimal scientific evidence and expert opinion consensus regarding a standardized US-based assessment protocol for low-risk PTMC.

Multi-UniFocality (MUF), in contrast to multifocality, in thyroid lesions: Relation to lymphocytic thyroiditis

Whereas multifocality typically concerns papillary thyroid carcinoma (PTC) without specification of intrathyroidal metastatic or independent nature of tumor foci, the designation of the latter as Multi-UniFocal (MUF) may be relevant for select cases. A case series involving multifocal thyroid lesions with divergent histopathological morphology and/or molecular profile, with molecular evaluation of multiple individual tumor foci per patient based on a next-generation sequencing approach, was retrospectively reviewed. Twenty-five patient cases with multifocal thyroid lesions suggestive of MUF, with 2-6 (median 3) tumor foci per patient, were described. Tumor lesions comprised diverse histopathology, including PTC, (E)FVPTC, NIFTP, FA, FTC, and oncocytic. Morphologically similar and/or diverse tumor foci harbored different molecular alterations (suggestive of non-shared clonality); with(out) coexistent similar foci harboring identical molecular alterations; or (partly) shared molecular alterations. MUF was associated with chronic lymphocytic thyroiditis in almost half of the cases. The recognition of MUF may justify the independent clinical consideration per individual tumor focus; as separate lesions albeit within a multifocal context. The potential clinical relevance and prognostic value of MUF remain to be further established.

Trends of the prevalence rate of central lymph node metastasis and multifocality in patients with low-risk papillary thyroid carcinoma after delayed thyroid surgery

Background

Active surveillance has been an option for patients with low-risk papillary thyroid carcinoma (PTC). However, whether delayed surgery leads to an increased risk of local tumor metastasis remain unclear. We sought to investigate the impact of observation time on central lymph node metastasis (CLNM) and multifocal disease in patients with low-risk PTC.

Methods

Patients who were diagnosed with asymptomatic low-risk PTC, and with a pathological maximum tumor size ≤1.5 cm by were included. The patients were classified into observation group and immediate surgery group, and subgroup analyses were conducted by observation time period. The prevalence of CLNM, lymph node (LN) involved >5, multifocal PTC and bilateral multifocal PTC were considered as outcome variables. The changing trend and risk ratio of prevalence over observation time were evaluated by Mann-Kendall trend test and Logistics regression.

Results

Overall, 3,427 and 1,860 patients were classified to the observation group and immediate surgery group, respectively. Trend tests showed that decreasing trends both on the prevalence of CLNM and LN involved >5 over the observation time, but the difference was not statistically significant, and the prevalence of multifocal PTC and bilateral multifocal PTC showed the significant decreasing trends. After adjustment, multivariate analysis showed no statistically significant difference between observed and immediate surgery groups in the four outcome variables.

Conclusion

In patients with subclinical asymptomatic low-risk PTC, observation did not result in an increased incidence of local metastatic disease, nor did the increased surgery extent in patients with delayed surgery compared to immediate surgery. These findings can strengthen the confidence in the active surveillance management for both doctors and patients.

Long-term efficacy of microwave ablation for multifocal papillary thyroid microcarcinoma: a 5-year follow-up study

OBJECTIVES

Microwave ablation (MWA) has achieved excellent long-term efficacy in treating unifocal papillary thyroid microcarcinoma (UPTMC). The therapeutic effect of this treatment on multifocal papillary thyroid microcarcinoma (MPTMC) is unknown. Therefore, we evaluated the long-term efficacy of MWA for low-risk MPTMC and to provide evidence-based medicine for the revision of clinical guidelines.

METHODS

This study included 66 MPTMC patients with a total of 158 lesions, all of whom received MWA. We collected and retrospectively analyzed the patients' follow-up data before MWA, at 1, 3, 6, and 12 months posttreatment and every 6 months thereafter until 5 years posttreatment. We evaluated the MWA complication rate, technical success rate (TSR), lesion volume reduction rate (VRR), and complete disappearance rate (CDR) during follow-up and in those patients with tumor progression and delayed surgery.

RESULTS

After 60 months of follow-up, all 158 lesions disappeared in 66 patients, and the volume was reduced from 43.82 mm3 to 0.00 mm3. The TSR and VRR were both 100%. The CDRs at 1 year, 2 years, and 3 years were 57.59%, 93.67%, and 100%, respectively. The complication rate was 3.03% (2/66), and the incidence of tumor progression was 3.03% (2/66), including one new intrathyroidal lesion and one cervical lymph node metastasis (LNM). These lesions were retreated with MWA, and the lesions disappeared during the follow-up period.

CONCLUSIONS

Ultrasound-guided MWA for low-risk MPTMC is safe and effective and may serve as an alternative option for patients who refuse surgery or active surveillance (AS).

CLINICAL RELEVANCE STATEMENT

This study concludes that ultrasound-guided microwave ablation for low-risk multifocal papillary thyroid microcarcinoma is safe and effective and may serve as an alternative option for patients who refuse surgery or active surveillance.

KEY POINTS

• Ultrasound-guided microwave ablation for low-risk multifocal papillary thyroid microcarcinoma is safe and effective. • During 5 years of follow-up, multifocal papillary thyroid microcarcinoma patients treated with microwave ablation had a favorable prognosis. • To provide evidence-based medicine for the revision of clinical guidelines.

The Incidence Trend and Management of Thyroid Cancer-What Has Changed in the Past Years: Own Experience and Literature Review

Because of ambiguous and widely debated observations concerning the incidence, trend, and management of TC, we performed this analysis. We drew attention to some events, such as "cancer screening activity", introduction of noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP) to TC types, possibility of papillary thyroid microcarcinoma (PTMC) active surveillance (AS), occurrence of personalized medicine in TC management, and, finally, COVID-19 pandemic time. Because of the opinion that all changes have been made mostly by PTC, we compared it to the remaining types of TC in terms of incidence, clinical and pathological characteristics, and treatment. We analyzed patients treated in a single surgical center in eastern Europe (Poland). The prevalence of TC significantly increased from 5.15% in 2008 to 13.84% in 2015, and then significantly decreased to 1.33% in 2022 when the COVID-19 pandemic lasted (p < 0.0001). A similar trend was observed for PTC, when the incidence significantly increased to 13.99% in 2015 and then decreased to 1.38% in 2022 (p < 0.0001). At that time, the NIFTP category was introduced, and observation of PTMC began. The prevalence of FTC and MTC also increased until 2015 and then decreased. Significant differences in age, types of surgery, necessity of reoperation, and pTNM between PTCs and other types of TCs were observed. The average age was significantly lower in PTC patients than in patients with the remaining types of TC (p < 0.0001). Four milestones, including NIFTP introduction, the possibility of PTMC AS, personalized cancer medicine, and the COVID-19 pandemic, may have influenced the general statistics of TC.

The value of total tumor diameter in unilateral multifocal papillary thyroid carcinoma: a propensity score matching analysis

Background

Tumor multifocality is frequently observed in papillary thyroid carcinoma (PTC). However, the maximum tumor diameter (MTD), currently utilized in various staging schemes, might not accurately indicate the level of aggressiveness exhibited by multifocal tumors. We aimed to investigate the relationship between total tumor diameter (TTD) and clinicopathological features of papillary thyroid carcinoma.

Methods

Retrospective data analysis was done on 1936 individuals who underwent complete thyroidectomy for PTC. Patients were classified into subgroups according to unilateral multifocality, central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM). The relationships of clinicopathological features among these groups were analyzed.

Results

Unilateral multifocality was observed in 117 patients. The clinicopathological features of the unilateral multifocal PTC were similar to the unifocal PTC with approximate TTD. The unilateral multifocality played no independent role in CLNM and LLNM. Moreover, the efficiency of TTD in predicting CLNM and LLNM was significantly higher than that of MTD.

Conclusion

In the case of unilateral multifocal PTC, TTD is a more accurate indicator of the biological characteristics of the tumor than MTD.

An Ultrasound-based Prediction Model for Occult Contralateral Papillary Thyroid Carcinoma in Adolescents and Young Adults

RATIONALE AND OBJECTIVES

To investigate the occult contralateral papillary thyroid carcinoma (PTC)-associated ultrasound (US) and clinical characteristics and establish a US-based model for the prediction of occult contralateral carcinoma in adolescents and young adults (AYAs) who were diagnosed with unilateral thyroid carcinoma preoperatively.

MATERIALS AND METHODS

From January 2015 to December 2020, patients who were diagnosed with unilateral thyroid carcinoma by preoperative US examination and underwent total thyroidectomy or thyroid lobectomy with more than 60 months of US follow-up at our hospital were retrospectively collected. Univariate and multivariate analyses were applied to identify the independent risk factors associated with occult contralateral PTC in AYAs, on which a prediction model was developed. The performance of the model was evaluated with accuracy, sensitivity, specificity, and the area under the receiver operating characteristic curve.

RESULTS

Occult contralateral PTC was found in 91 of 365 (24.9%) PTC patients with a median age at diagnosis of 26 years (interquartile range, 24-29 years). The multivariate analysis indicated that the presence of contralateral benign nodule, intra-tumoral calcification, and intraglandular dissemination were significantly associated with occult contralateral PTC in AYAs. The prediction model, which incorporated all independent predictors, yielded an area under the receiver operating characteristic curve of .661 (95% CI: .602-.719). The accuracy, sensitivity and specificity were 67.9%, 54.9%, and 72.3%, respectively.

CONCLUSION

The US-based prediction model proposed here exhibited a favorable performance for predicting occult contralateral PTC, which might be used to determine the appropriate extent of surgery for AYAs who had a preoperative diagnosis of unilateral thyroid carcinoma.

Evaluation of serum B7-H3 expression, ultrasound and clinical characteristics to predict the risk of cervical lymph node metastases in papillary thyroid carcinoma by nomogram

BACKGROUND

Improving the preoperative diagnosis of cervical lymph node metastasis (LNM) will help improve the clinical outcomes of papillary thyroid carcinoma (PTC) patients. B7-H3, as an immune checkpoint of the B7 family, is highly expressed in PTC tissues and related to LNM and prognosis. We aimed to explore the clinical values of serum B7-H3 (sB7-H3) in predicting LNM in PTC by a nomogram prediction model.

METHODS

From September 2019 to May 2021, a total of 344 PTC patients with primary surgery in our hospital were enrolled in this research. Enzyme-linked Immunosorbent Assay (ELISA) was used to detect sB7-H3 from the peripheral blood of PTC patients and normal controls. We created a nomogram prediction model in combination with sB7-H3 expression, clinical and ultrasound characteristics to predict LNM in the early stage.

RESULTS

Gender (p = 0.001), age (p = 0.015), tumor size (p < 0.001), number of tumors (p = 0.021) and sB7-H3 expression (p = 0.003) were independent risk factors for LNM in PTC. All the factors were included in the nomogram. The area under the curve (AUC) was 73.9% (95% CI, 68.12%-79.69%).

CONCLUSION

The nomogram is helpful in assessing the risk of LNM in PTC. sB7-H3 has excellent potential in predicting LNM in patients with PTC as an adjunctive ultrasound tool.

Risks of central lymph node metastasis in papillary thyroid carcinoma with or without multifocality in at least one lobe: A multi-center analysis

PURPOSES

To quantitatively predict central lymph node metastasis (CLNM) risks by comparing the clinicopathological features of different multifocal manifestations in papillary thyroid carcinomas (PTC) patients.

METHODS

A total of 998 PTC patients from three medical centers were retrospectively analyzed.

RESULTS

PTC patients with multifocal lesions in at least one thyroid lobe (MF group) yielded significantly higher CLNM rates than those with unifocal lesions in one or both lobes (UF group). Multifocality in at least one lobe rather than bilateral presence was confirmed to be an independent risk factor of CLNM for PTC patients. Four (age, gender, maximum tumor diameter, and thyroid capsular invasion (TCI)) and three (age, gender, and TCI) factors were proven to be independent risk factors of CLNM for patients within UF and MF groups, respectively. Predictive nomograms were established for these patients based on their respective high-risk factors. The accuracy and validity of these newly-created models were verified using C-index and calibration curves. Patients within UF and MF groups possessing significantly different CLNM risks based on individualized nomogram risk scores were further classified into different subgroups. A detailed CLNM risk stratification flow chart covering all PTC patients was then established.

CONCLUSION

A meticulous evaluating system that quantifiesCLNM risk for PTC patients with unifocal lesions in one or both lobes and multifocal lesions in at least one lobe was established.

Optimal Surgical Extent in Patients with Unilateral Multifocal Papillary Thyroid Carcinoma

Multifocality increases the risk of recurrence in patients with papillary thyroid carcinoma (PTC); however, it is unclear whether multifocality justifies more extensive or aggressive surgical treatment. Here, we evaluated the effect of the operative extent on the recurrence-free survival (RFS) of patients with multifocal PTC. Between 2010 and 2019, 718 patients with unilateral multifocal PTC were enrolled; 115 patients (16.0%) underwent ipsilateral thyroid lobectomy, and 606 patients (84.0%) underwent total thyroidectomy. With a mean follow up of 5.2 years, RFS was comparable between the total thyroidectomy and lobectomy groups (p = 0.647) after adjusting for potential confounders. Multivariable Cox regression analysis also demonstrated that the operative extent was not an independent predictor of recurrence (HR 1.686, 95% CI: 0.321-8.852). Subgroup analyses further indicated that both total thyroidectomy and thyroid lobectomy resulted in comparable RFS for multifocal PTC patients with other high-risk factors, including tumor size > 1 cm (p = 0.711), lymph node metastasis (p = 0.536), and intermediate ATA risk of recurrence (p = 0.682). In conclusion, thyroid lobectomy was not associated with the risk of recurrence in patients with multifocal PTCs. Multifocality in PTC may not always require aggressive surgery.

Impact of Multifocality on the Recurrence of Papillary Thyroid Carcinoma

The incidence of thyroid cancer has dramatically increased over the last few decades, and up to 60% of patients have multifocal tumors. However, the prognostic impact of multifocality in patients with papillary thyroid carcinoma (PTC) remains unestablished and controversial. We evaluate whether multifocality can predict the recurrence of PTC. A total of 1249 patients who underwent total thyroidectomy for PTC at the Ewha Medical Center between March 2012 and December 2019 were reviewed. In this study, multifocality was found in 487 patients (39.0%) and the mean follow-up period was 5.5 ± 2.7 years. Multifocality was associated with high-risk features for recurrence, including extrathyroidal extension, lymph node metastasis, and margin involvement. After adjustment of those clinicopathological features, 10-year disease-free survival was 93.3% in patients with multifocal tumors, whereas those with unifocal disease showed 97.6% (p = 0.011). Multivariate Cox regression analysis indicated that male sex (HR 2.185, 95% CI 1.047–4.559), tumor size (HR 1.806, 95% CI 1.337–2.441), N1b LN metastasis (HR 3.603, 95% CI 1.207–10.757), and multifocality (HR 1.986, 95% CI 1.015–3.888) were independent predictors of recurrence. In conclusion, multifocality increased the risk of recurrence in patients with PTC. Patients with multifocal PTCs may need judicious treatment and follow-up approaches.

Clinical and pathological characteristics of multiple primary malignant neoplasms cases

OBJECTIVES

To investigate the clinical and pathological features of multiple primary malignant neoplasms (MPMNs) cases.

METHODS

The clinical data of 24 105 tumour patients admitted to Jiangsu Cancer Hospital in 2018 were retrospectively reviewed, and 270 patients with MPMNs were selected as the research subjects. Among them, 101 cases of synchronous carcinoma (SC) and 92 cases of metachronous carcinoma (MC) were divided into groups for statistical analysis. Univariate and multivariate cox regression analyses were conducted using SPSS 22.0 software.

RESULTS

Among 24 105 cases, there was a male-to-female ratio of 1.45:1. Compared with MC cases, SC patients have a higher proportion of male cases. Primary neoplasms in gastric cancer, head and neck cancer, oesophageal cancer and colon cancer occupied most cases in male MPMNs, while primary breast cancer ranked first in female MPMNs. In addition, the leading secondary neoplasms were duodenal carcinoma, lung cancer and male MPMNs and lung cancer in female MPMNs. As for SC MPMNs, primary neoplasms were occupied by lung cancer, gastric cancer and oesophageal cancer, while the secondary neoplasms were mostly consisted of oesophageal cancer and lung cancer. Finally, the MC MPMNs were mostly consisted of breast cancer and gastric cancer as primary neoplasms, while lung cancer and oesophageal cancer as secondary neoplasms.

CONCLUSIONS

Screening for primary cancer should be strengthened over the age of 50 years for male patients with gastric cancer or female patients with breast cancer to reduce or monitor the occurrence of MPMNs.

Performance of Contrast-Enhanced Ultrasound in Thyroid Nodules: Review of Current State and Future Perspectives

Ultrasound has been established as a baseline imaging technique for thyroid nodules. The main advantage of adding CEUS is the ability to assess the sequence and intensity of vascular perfusion and hemodynamics in the thyroid nodule, thus providing real-time characterization of nodule features, considered a valuable new approach in the determination of benign vs. malignant nodules. Original studies, reviews and six meta-analyses were included in this article. A total of 624 studies were retrieved, and 107 were included in the study. As recognized for thyroid nodule malignancy risk stratification by US, for acceptable accuracy in malignancy a combination of several CEUS parameters should be applied: hypo-enhancement, heterogeneous, peripheral irregular enhancement in combination with internal enhancement patterns, and slow wash-in and wash-out curve lower than in normal thyroid tissue. In contrast, homogeneous, intense enhancement with smooth rim enhancement and "fast-in and slow-out" are indicative of the benignity of the thyroid nodule. Even though overlapping features require standardization, with further research, CEUS may achieve reliable performance in detecting or excluding thyroid cancer. It can also play an operative role in guiding ablation procedures of benign and malignant thyroid nodules and metastatic lymph nodes, and providing accurate follow-up imaging to assess treatment efficacy.

The Differences Between Multifocal and Unifocal Papillary Thyroid Carcinoma in Unilateral Lobe: A Meta-Analysis

Background

As many inconsistent reports on the clinical manifestations and prognosis between unilateral unifocal PTC (UUPTC) and unilateral multifocal PTC (UMPTC), identifying the difference should guide management. The purpose of this study was to investigate other additional differences between UUPTC and UMPTC in addition to their difference in the number of cancer foci.

Data Sources

A systematic literature search was conducted in the PubMed and Web of Science databases for relevant studies published before December 31, 2020. Their reference lists were also reviewed.

Review Methods

Two reviewers independently extracted data and assessed the quality of eligible studies. Studies on patients who underwent an open thyroidectomy with or without neck dissection were included. Data were analyzed using the RevMan 5.3 software.

Results

Fifteen studies comprising 9,665 patients were selected for the meta-analysis. UMPTC occurred in 10% to 36% of all PTC cases. There were no significant differences between UMPTC and UUPTC patients in age, gender, tumor size, and extrathyroidal extension (ETE). However, significant differences (P < 0.05) between UMPTC and UUPTC patients were observed in central lymph node metastasis (CLNM), lateral lymph node metastasis (LLNM), tumor-node-metastasis (TNM) stage I+II, TNM stage III+IV, the recurrence/persistence of the UMPTC group after total thyroidectomy and overall recurrence/persistence.

Conclusion

UMPTC patients are more likely to have CLNM, LLNM, more advanced TNM stage, and recurrence/persistence than UUPTC patients. Compared with UUPTC, UMPTC patients should undergo central lymph node dissection, and pay more attention to LLNM, TNM stage and recurrence/persistence during the follow-up.

Association of Multifocality With Prognosis of Papillary Thyroid Carcinoma: A Systematic Review and Meta-analysis

Importance

Multifocality is common in papillary thyroid carcinoma (PTC), but it is unclear whether multifocal tumors are associated with tumor recurrence or cancer-specific survival.

Objective

To compare tumor recurrence rates in patients with multifocal vs unifocal PTCs.

Data Sources

We searched PubMed, SCOPUS, Web of Science Core Collection, and Cochrane Database of Systematic Reviews for pertinent studies published in English from inception to June 30, 2020.

Study Selection

The search strategy yielded 26 studies that compared tumor recurrence in patients with multifocal vs unifocal PTC.

Data Extraction and Synthesis

Data was extracted in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-analyses guideline. Characteristics of study populations and hazard ratio (HR) of multifocality were independently extracted by 2 investigators.

Main Outcomes and Measures

The primary outcome was tumor recurrence and the secondary outcome was cancer-specific survival. Subgroup analysis of the primary outcome was based on primary tumor size, number of tumor foci, and patient age.

Results

Among 26 studies with a total of 33 976 patients, recurrence rates were significantly higher in patients with multifocal PTC than in those with unifocal PTC (pooled HR, 1.81; 95% CI, 1.52-2.14). Cancer-specific survival was comparable between the groups (HR, 1.19; 95% CI, 0.85-1.68). In subgroup analyses, the HRs of multifocality for recurrence were associated with primary tumor size (HRs for PTC ≤1 cm and >1 cm were 1.81 and 1.90, respectively), number of tumor foci (HRs for 2 foci and ≥3 foci were 1.45 and 1.95, respectively), and patient age (HRs for pediatric and adult patients were 3.19 and 1.89, respectively).

Conclusions and Relevance

This systematic review with meta-analysis found that multifocality was significantly associated with an increased risk of recurrence in patients with PTC, while cancer-specific survival showed no difference. Differences in tumor size, number of tumor foci, and patient age should be considered when interpreting the multifocality and the risk of recurrence.

Thyroid Carcinoma: Phenotypic Features, Underlying Biology and Potential Relevance for Targeting Therapy

Thyroid carcinoma consists a group of phenotypically heterogeneous cancers. Recent advances in biological technologies have been advancing the delineation of genetic, epigenetic, and non-genetic factors that contribute to the heterogeneities of these cancers. In this review article, we discuss new findings that are greatly improving the understanding of thyroid cancer biology and facilitating the identification of novel targets for therapeutic intervention. We review the phenotypic features of different subtypes of thyroid cancers and their underlying biology. We discuss recent discoveries in thyroid cancer heterogeneities and the critical mechanisms contributing to the heterogeneity with emphases on genetic and epigenetic factors, cancer stemness traits, and tumor microenvironments. We also discuss the potential relevance of the intratumor heterogeneity in understanding therapeutic resistance and how new findings in tumor biology can facilitate designing novel targeting therapies for thyroid cancer.

The clonal origin of multifocal papillary thyroid cancer: intrathyroidal spread or independent tumors?

Multifocality is a common finding in papillary thyroid cancer but the molecular pathogenesis, prognosis and management of multifocal papillary thyroid cancer are debated. The clonal origin of multifocal papillary thyroid cancer represents a controversial aspect, as two opposite viewpoints have been proposed: independent origin or intraglandular spread. Different approaches have been used for inferring the clonality of multifocal papillary thyroid cancer, including X-chromosome inactivation, mutational analysis, determination of loss of heterozygosity and, more recently, next-generation sequencing. Next-generation sequencing, able to provide information on genetic heterogeneity and phylogenetic evolution in multifocal tumors, represents the most reliable approach. While most evidences indicated an independent origin of multifocal papillary thyroid cancer, a minority of studies suggested that multifocal papillary thyroid tumors might be monoclonally derived. This discrepancy may reflect technical limitations; nevertheless, studies based on next-generation sequencing indicated that both independent and clonal origins are possible. The co-existence of multiple tumors implies a high degree of genetic heterogeneity, which may influence the best and targeted therapeutic strategy. On the other hand, intrathyroidal dissemination may indicate metastatic potential of the dominant tumor, thereby prompting more aggressive treatments. In conclusion, data available in the literature indicated that multifocal papillary thyroid cancer may derived from both intraglandular spread and independent tumor foci. The understanding of the clonal origin of multifocal papillary thyroid tumors might represent an important issue in patient treatment.

Predictive factors of contralateral occult carcinoma in patients with papillary thyroid carcinoma: a retrospective study

BACKGROUND

The surgical approach toward unilateral papillary thyroid carcinoma (PTC) has been in controversy. One of the concerns is the existence of contralateral occult carcinoma, which could cause relapse and even lead to re-operation if not dealt with. This study aims to find out risk factors related to contralateral occult PTC, in order to facilitate in surgical approach decision for PTC.

METHODS

A total of 921 PTC patients who underwent total/near-total thyroidectomy and central lymph node dissection (CND) with/without lateral lymph node dissection (LND) from January 2014 to Sept 2017 in Guangdong General Hospital were assessed retrospectively. The relations between contralateral occult PTC and clinicopathologic characteristics of PTC were analyzed by univariate and multivariate logistic regression.

RESULTS

The incidence of contralateral occult carcinoma in patients with PTC was 16.7% (154 of 921 cases). Univariate analysis showed that multifocality of the primary carcinoma (P=0.000), lymph node metastasis (P=0.001), pathologic tumor size (P=0.014) and contralateral benign nodule (P=0.000) were significantly associated with the increased incidence of contralateral occult PTC. No significant correlations were found between contralateral carcinoma and other variables such as gender (P=0.338), age (P=0.283), BRAF mutation (P=0.187) or extrathyroidal extension (P=0.423). Multivariate logistic regression analysis revealed that contralateral benign nodule (P=0.000), multifocality (P=0.000) and lymph node metastasis (P=0.009) were independent predictors of bilateral PTC of patients whose pre-operation ultrasound (US) show a unilateral carcinoma.

CONCLUSIONS

Lymph node metastasis, contralateral benign nodule and multifocality are independent predictors of contralateral occult PTC. For unilateral PTC patients with one or more of these factors, total/near-total thyroidectomy should be considered when making surgical approach decisions.

Clonality analysis of pulmonary tumors by genome-wide copy number profiling

Multiple tumors in patients are frequently diagnosed, either synchronous or metachronous. The distinction between a second primary and a metastasis is important for treatment. Chromosomal DNA copy number aberrations (CNA) patterns are highly unique to specific tumors. The aim of this study was to assess genome-wide CNA-patterns as method to identify clonally related tumors in a prospective cohort of patients with synchronous or metachronous tumors, with at least one intrapulmonary tumor. In total, 139 tumor pairs from 90 patients were examined: 35 synchronous and 104 metachronous pairs. Results of CNA were compared to histological type, clinicopathological methods (Martini-Melamed-classification (MM) and ACCP-2013-criteria), and, if available, EGFR- and KRAS-mutation analysis. CNA-results were clonal in 74 pairs (53%), non-clonal in 33 pairs (24%), and inconclusive in 32 pairs (23%). Histological similarity was found in 130 pairs (94%). Concordance between histology and conclusive CNA-results was 69% (74 of 107 pairs: 72 clonal and two non-clonal). In 31 of 103 pairs with similar histology, genetics revealed non-clonality. In two out of four pairs with non-matching histology, genetics revealed clonality. The subgroups of synchronous and metachronous pairs showed similar outcome for the comparison of histological versus CNA-results. MM-classification and ACCP-2013-criteria, applicable on 34 pairs, and CNA-results were concordant in 50% and 62% respectively. Concordance between mutation matching and conclusive CNA-results was 89% (8 of 9 pairs: six clonal and two non-clonal). Interestingly, in one patient both tumors had the same KRAS mutation, but the CNA result was non-clonal. In conclusion, although some concordance between histological comparison and CNA profiling is present, arguments exist to prefer extensive molecular testing to determine whether a second tumor is a metastasis or a second primary.

Predicting links between tumor samples and genes using 2-Layered graph based diffusion approach

Background

Determining the association between tumor sample and the gene is demanding because it requires a high cost for conducting genetic experiments. Thus, the discovered association between tumor sample and gene further requires clinical verification and validation. This entire mechanism is time-consuming and expensive. Due to this issue, predicting the association between tumor samples and genes remain a challenge in biomedicine.

Results

Here we present, a computational model based on a heat diffusion algorithm which can predict the association between tumor samples and genes. We proposed a 2-layered graph. In the first layer, we constructed a graph of tumor samples and genes where these two types of nodes are connected by “hasGene” relationship. In the second layer, the gene nodes are connected by “interaction” relationship. We applied the heat diffusion algorithms in nine different variants of genetic interaction networks extracted from STRING and BioGRID database. The heat diffusion algorithm predicted the links between tumor samples and genes with mean AUC-ROC score of 0.84. This score is obtained by using weighted genetic interactions of fusion or co-occurrence channels from the STRING database. For the unweighted genetic interaction from the BioGRID database, the algorithms predict the links with an AUC-ROC score of 0.74.

Conclusions

We demonstrate that the gene-gene interaction scores could improve the predictive power of the heat diffusion model to predict the links between tumor samples and genes. We showed the efficient runtime of the heat diffusion algorithm in various genetic interaction network. We statistically validated our prediction quality of the links between tumor samples and genes.

Electronic supplementary material

The online version of this article (10.1186/s12859-019-3056-2) contains supplementary material, which is available to authorized users.

Investigation of the clonal origin of multifocal papillary thyroid carcinoma according to the X-chromosome inactivation pattern

Patients with papillary thyroid carcinoma (PTC) usually have multiple tumors, or foci. It remains unclear if these foci originate from independent tumors or a single tumor mass. The present study included 89 female patients with bilateral PTC who had been treated with a total thyroidectomy. An X-chromosome inactivation assay was used to examine the clonal origin of the tumors according to the status of the X-linked human androgen receptor gene. Of the 89 patients, 5 were informative. The X-chromosome inactivation pattern was the same in multiple foci in 3 cases, indicating a monoclonal origin of the tumors. In 1 case, the X chromosome inactivation pattern was different between the tumors. Mixed patterns were observed in 1 case. The results of the present study suggest that in certain cases of multifocal PTC, tumors arise independently, whereas in other cases, separate foci are the outcome of intra-thyroid spread by a single tumor mass.

Thyroid cancers of follicular origin in a genomic light: in-depth overview of common and unique molecular marker candidates

In recent years, thyroid malignances have become more prevalent, especially among women. The most common sporadic types of thyroid tumors of follicular origin include papillary, follicular and anaplastic thyroid carcinomas. Although modern diagnosis methods enable the identification of tumors of small diameter, tumor subtype differentiation, which is imperative for the correct choice of treatment, is still troublesome. This review discusses the recent advances in the field of molecular marker identification via next-generation sequencing and microarrays. The potential use of these biomarkers to distinguish among the most commonly occurring sporadic thyroid cancers is presented and compared. Geographical heterogeneity might be a differentiator, although not necessarily a limiting factor, in biomarker selection. The available data advocate for a subset of mutations common for the three subtypes as well as mutations that are unique for a particular tumor subtype. Tumor heterogeneity, a known issue occurring within solid malignancies, is also discussed where applicable. Public databases with datasets derived from high-throughput experiments are a valuable source of information that aid biomarker research in general, including the identification of molecular hallmarks of thyroid cancer.

Association between diffuse lymphocytic infiltration and papillary thyroid cancer aggressiveness according to the presence of thyroid peroxidase antibody and BRAFV600E mutation

BACKGROUND

Diffuse lymphocytic infiltration (DLI) is frequently found with papillary thyroid cancer (PTC), so there has been long interest in how it affects the characteristics of PTC. This purpose of this study was to define the association between DLI and PTC aggressiveness according to thyroperoxidase antibody (TPOAb) and B-type Raf (BRAF)^V600E mutation positivity.

METHODS

There were 1879 patients with PTC who underwent surgery and were enrolled in this study. Clinicopathologic characteristics were compared between groups according to the presence of DLI and TPOAb. Multiple logistic regression analysis was conducted to assess odds ratio (OR) for each dependent variable (BRAF^V600E mutation, tumor size >1.0 cm, multifocality, extrathyroidal extension, and lymph node metastasis) of each group according to the presence of DLI and TPOAb, with the group with neither DLI or TPOAb (DLI-negative TPOAb-negative PTC) as the reference.

RESULTS

The DLI-positive PTC showed more frequent multifocality and less frequent BRAF^V600E mutation than DLI-negative PTC. Among patients with DLI-positive PTC, extrathyroidal extension and BRAF^V600E mutation was less frequent when serum TPOAb was positive. In multiple logistic regressions, DLI-positive TPOAb-positive PTC showed a high OR for multifocality (1.410; P = .017), but low ORs for BRAF^V600E mutation (0.521; P < .001) and extrathyroidal extension (0.691; P = .008). The patients with DLI-positive TPOAb-positive PTCs showed a high OR for multifocality (1.588; P = .002), and high ORs for tumor size >1.0 cm (2.205; P = .019) and lymph node metastasis (2.005; P = .032) in subgroup analyses of PTC with wild-type BRAF. The DLI-negative TPOAb-positive group was not associated with any tumor aggressiveness-related variables.

CONCLUSION

Although DLI was associated with multifocality regardless of TPOAb positivity, it was associated with an indolent feature when TPOAb was positive but with aggressive features in PTC with wild-type BRAF when TPOAb was negative. The TPOAb and BRAF status may help to define the clinical implication of lymphocytic infiltration found with PTC.

Heterogeneity of Thyroid Cancer

There are 5 main histological types of thyroid cancers (TCs): papillary, follicular (also known as differentiated), poorly differentiated, anaplastic (the most aggressive form), and medullary TC, and only the latter arises from thyroid C cells. These different forms of TCs show significant variability, both among and within tumours. This great variation is particularly notable among the first 4 types, which all originate from thyroid follicular cells. Importantly, this heterogeneity is not limited to histopathological diversity only but is also manifested as variation in several genetic and/or epigenetic alterations, the numbers of interactions between the tumour and surrounding microenvironment, and interpatient differences, for example. All these factors contribute to the great complexity in the development of a tumour from cancer cells. In the present review, we summarise the knowledge accumulated about the heterogeneity of TCs. Further research in this direction should help to gain a better understanding of the underlying mechanisms contributing to the development and diversity of TCs, paving the way toward more effective treatment strategies.

Identifying the clonal relationship model of multifocal papillary thyroid carcinoma by whole genome sequencing

PURPOSE

To evaluate the application of whole genome sequencing (WGS) in determining the inter-foci clonal relationship of multifocal papillary thyroid carcinoma (mPTC).

METHODS

After reviewing PTC patient profiles, 8 cancer foci and germline control samples from 3 mPTC patients were analyzed by WGS. Single nucleotide variations (SNVs), copy number variation (CNV), structural variation and mutational signature were examined.

RESULTS

The multifocality rate of PTC was 35.1% and mPTC were shown to have larger primary tumor diameter, higher rate of lymph node metastasis and less number of accompanying non-cancerous lesions than single PTC in one or both gender groups. Out of the 8 cancer foci, 5 foci were identified as clonal-independent model with the rest 3 foci as clonal-derived model according to exonic SNVs spectrum. Non-exonic mutations provided compelling evidence at the genome-wide level for the classification. Specific CNV and 12 mutational signatures were also identified.

CONCLUSIONS

WGS could be an impressive tool in clonal relationship determination of PTC by providing a panoramic view of genome-wide somatic mutations. The substantial sequencing data provided additional information that could help studying the mechanism of carcinogenesis.

Therapeutic Outcomes of Patients with Multifocal Papillary Thyroid Microcarcinomas and Larger Tumors

A retrospective review of 626 patients with multifocal papillary thyroid carcinoma (PTC) including 147 patients (23.5%) with multifocal papillary thyroid microcarcinoma (PTMC) from a total of 2,536 patients with PTC who visited the Chang Gung Medical Center in Linkou, Taiwan, was performed. A comparison of the clinical features between 626 multifocal and 1,910 solitary PTC cases showed that patients in the multifocal PTC group were older and had a smaller mean tumor size, a more advanced tumor-node-metastasis (TNM) stage, and a higher percentage of nonremission status compared to patients in the solitary PTC group. Of the 626 patients with multifocal PTC, the group with larger tumors showed a more advanced TNM stage, a higher percentage of lymph node metastasis and soft tissue invasion, and a higher nonremission rate compared to the multifocal PTMC group. Of the 626 patients with multifocal PTC, 25 patients (4%) died during a mean follow-up period of 7.1 ± 5.3 years. Kaplan-Meier survival curves showed a significantly lower survival rate associated with multifocal PTMC compared to that with solitary PTMC.

Next-generation sequencing in thyroid cancer

Next-generation sequencing (NGS) in thyroid cancer allows for simultaneous high-throughput sequencing analysis of variable genetic alterations and provides a comprehensive understanding of tumor biology. In thyroid cancer, NGS offers diagnostic improvements for fine needle aspiration (FNA) cytology of thyroid with indeterminate features. It also contributes to patient management, providing risk stratification of patients based on the risk of malignancy. Furthermore, NGS has been adopted in cancer research. It is used in molecular tumor classification, and molecular prediction of recurrence and metastasis in papillary thyroid carcinoma. This review covers previous NGS analyses in variable types of thyroid cancer, where samples including FNA cytology, fresh frozen tissue, and formalin-fixed, paraffin-embedded tissues were used. This review also focuses on the clinical and research implications of using NGS to study and treat thyroid cancer.

Relevance of BRAF and NRAS mutations in the primary tumor and metastases of papillary thyroid carcinomas

BACKGROUND

Multifocality of papillary thyroid carcinoma (PTC) is common. BRAF and NRAS mutations are the most frequent genetic alterations in PTC. The purpose of this study was to determine the distribution and relevance of BRAF^T1799A and NRAS mutations in PTC.

METHODS

BRAF^T1799A and NRAS mutations were evaluated in 195 intrathyroid or metastatic foci from 29 patients with multifocal PTC.

RESULTS

BRAF^T1799A mutation was positive in 46.7% of the 59 intrathyroid and 136 metastatic foci (91/195 foci). Heterogeneous BRAF pattern was observed in 51.7% patients (15/29 patients). Irrespective of BRAF status at diagnosis (thyroid or nodes), all patients with recurrent PTC presented BRAF-mutated metastases during follow-up. All foci were negative for NRAS mutations.

CONCLUSION

BRAF but not NRAS mutations were heterogeneously distributed among primary tumor, nodal sites, and recurrent disease. The BRAF status of metastases generated during the follow-up can differ from the status of foci at diagnosis. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1772-1779, 2016.

Clonality analysis of multifocal papillary thyroid carcinoma by using genetic profiles

Papillary thyroid carcinoma (PTC) is the most common adult thyroid malignancy and often presents with multiple anatomically distinct foci within the thyroid, known as multifocal papillary thyroid carcinoma (MPTC). The widespread application of the next-generation sequencing technologies in cancer genomics research provides novel insights into determining the clonal relationship between multiple tumours within the same thyroid gland. For eight MPTC patients, we performed whole-exome sequencing and targeted region sequencing to identify the non-synonymous point mutations and gene rearrangements of distinct and spatially separated tumour foci. Among these eight MPTCs, completely discordant mutational spectra were observed in the distinct cancerous nodules of patients MPTC1 and 5, suggesting that these nodules originated from independent precursors. In another three cases (MPTC2, 6, and 8), the distinct MPTC foci of these patients had no other shared mutations except BRAF V600E, also indicating likely independent origins. Two patients (MPTC3 and 4) shared almost identical mutational spectra amongst their separate tumour nodules, suggesting a common clonal origin. MPTC patient 7 had seven cancer foci, of which two foci shared 66.7% of mutations, while the remaining cancer foci displayed no common non-synonymous mutations, indicating that MPTC7 has multiple independent origins accompanied by intraglandular disease dissemination. In this study, we found that 75% of MPTC cases arose as independent tumours, which supports the field cancerization hypothesis describing multiple malignant lesions. MPTC may also arise from intrathyroidal metastases from a single malignant clone, as well as multiple independent origins accompanied by intrathyroidal metastasis.

BRAF V600E and risk stratification of thyroid microcarcinoma: a multicenter pathological and clinical study

Studies from single institutions have analyzed BRAF in papillary microcarcinomas, sometimes with contradictory results. Most of them have provided limited integration of histological and clinical data. To obtain a comprehensive picture of BRAF V600E-mutated microcarcinomas and to evaluate the role of BRAF testing in risk stratification we performed a retrospective multicenter analysis integrating microscopical, pathological, and clinical information. Three hundred and sixty-five samples from 300 patients treated at six medical institutions covering different geographical regions of Italy were analyzed with central review of all cases. BRAF V600E statistical analysis was conducted on 298 microcarcinomas from 264 patients after exclusion of those that did not meet the required criteria. BRAF V600E was identified in 145/298 tumors (49%) including the following subtypes: 35/37 (95%, P<0.0001) tall cell and 72/114 (64%, P<0.0001) classic; conversely 94/129 follicular variant papillary microcarcinomas (73%, P<0.0001) were BRAF wild type. BRAF V600E-mutated microcarcinomas were characterized by markedly infiltrative contours (P<0.0001) with elongated strings of neoplastic cells departing from the tumor, and by intraglandular tumor spread (P<0.0001), typically within 5 mm of the tumor border. Multivariate analysis correlated BRAF V600E with specific microscopic features (nuclear grooves, optically clear nuclei, tall cells within the tumor, and tumor fibrosis), aggressive growth pattern (infiltrative tumor border, extension into extrathyroidal tissues, and intraglandular tumor spread), higher American Thyroid Association recurrence risk group, and non-incidental tumor discovery. The following showed the strongest link to BRAF V600E: tall cell subtype, many neoplastic cells with nuclear grooves or with optically clear nuclei, infiltrative growth, intraglandular tumor spread, and a tumor discovery that was non-incidental. BRAF V600E-mutated microcarcinomas represent a distinct biological subtype. The mutation is associated with conventional clinico-pathological features considered to be adverse prognostic factors for papillary microcarcinoma, for which it could be regarded as a surrogate marker. BRAF analysis may be useful to identify tumors (BRAF wild type) that have negligible clinical risk.

BRAF Testing in Multifocal Papillary Thyroid Carcinoma

BACKGROUND

BRAF V600E mutation is associated with poor prognosis in patients with papillary thyroid carcinoma (PTC). PTC is often multifocal, and there are no guidelines on how many tumors to test for BRAF mutation in multifocal PTC.

METHODS

Fifty-seven separate formalin-fixed and paraffin-embedded PTCs from twenty-seven patients were manually macrodissected and tested for BRAF mutation using a commercial allele-specific real-time polymerase chain reaction-based assay (Entrogen, Woodland Hills, CA). Data related to histologic characteristics, patient demographics, and clinical outcomes were collected.

RESULTS

All mutations detected were BRAF V600E. Seventeen patients (63%) had concordant mutation status in the largest and second-largest tumors (i.e., both were positive or both were negative). The remaining ten patients (37%) had discordant mutation status. Six of the patients with discordant tumors (22% overall) had a BRAF-negative largest tumor and a BRAF-positive second-largest tumor. No histologic feature was found to help predict which cases would be discordant.

CONCLUSIONS

Patients with multifocal PTC whose largest tumor is BRAF-negative can have smaller tumors that are BRAF-positive. Therefore, molecular testing of more than just the dominant tumor should be considered. Future studies are warranted to establish whether finding a BRAF mutation in a smaller tumor has clinical significance.

Multicentric occurrence of multiple papillary thyroid carcinomas--HUMARA and BRAF mutation analysis

Papillary thyroid carcinomas (PTCs) occasionally form multiple tumor foci in different sites of the same thyroid gland. However, it is controversial whether discrete nodules of PTC arise independently (multicentric occurrence) or are seeded from a single tumor via lymphatic channels (intraglandular metastasis). In order to determine the clonal origin of multiple PTCs, we examined X-chromosome inactivation patterns using a human androgen receptor gene-based assay (HUMARA) and the BRAF mutation using allele-specific PCR (AS-PCR) in 32 microdissected cancerous tissues from 14 Japanese women with multifocal PTC. All tumor foci were greater than 3 mm in size and met the criteria for microscopic classical PTC. Samples from 13 of the 14 patients were informative based on HUMARA. Tumor foci from two cases (15.4%) displayed a discordant X-chromosome inactivation pattern. Foci from the other 11 cases (84.6%) showed a concordant inactivation pattern of the X-chromosome. AS-PCR indicated that BRAF mutational status between the tumor foci was discordant in three (25%) and concordant in nine (75%) of 12 available cases. When the results of these two molecular analyses were combined, 28.6% of the cases were discordant in X-chromosome inactivation pattern and/or BRAF mutation, suggesting multicentric origin. Some of the remaining concordant cases also may be of multicentric origin. These results support a hypothesis that multicentric occurrence in multiple PTCs may be common, possibly greater than 30%. Although the exact mechanism of multicentric occurrence is still unclear, our findings contribute to the understanding the histogenesis of papillary thyroid carcinoma.

Clinical significance of papillary thyroid cancer risk loci identified by genome-wide association studies

Four single nucleotide polymorphisms (SNPs) have been reported to be associated with thyroid cancer risk in two genome-wide association studies (GWASs) and were validated in a Chinese population. Because of a lack of further clinical and functional evidence, the clinical significances of these SNPs remain unknown. Four GWAS-identified SNPs of papillary thyroid cancer (PTC), rs965513, rs944289, rs966423 and rs2439302, were genotyped in a case-control study of 838 patients with PTC and 501 patients with benign thyroid tumor (BTT) from the Chinese Han population. The associations between these SNPs, clinicopathologic features, and the outcome of the PTC patients were examined. The CT and CT + TT genotypes of rs966423 were more common in PTC patients with extrathyroidal extension and more advanced T stage. The TC and TC + CC genotypes and the C allele of rs944289 were significantly less frequent in patients with multifocal disease. No correlation was observed between GWAS-identified SNPs and disease persistence of PTC after a short-term follow-up. Significantly different allele distributions between the PTC and BTT groups were observed for all four selected SNPs. Individuals with more than five risk alleles were 8.84-fold (95% CI 3.23-24.17) more likely to suffer from PTC compared with those with zero or 1 risk allele. GWAS-identified SNPs affect the individual predisposition to PTC without interacting with existing Hashimoto thyroiditis and BTT lesions. GWAS-identified SNPs were associated with certain clinicopathologic features of PTC, and may contribute to identifying PTC patients with different clinical patterns. Large prospective studies are required to further evaluate the diagnostic and prognostic power of these genetic markers.

Diagnostic value of contrast-enhanced ultrasound in thyroid nodules with calcification

The aim of this study was to investigate the diagnostic values of conventional ultrasound and contrast-enhanced ultrasound (CEUS) in benign and malignant thyroid nodules with calcification. Conventional ultrasound and CEUS were performed in 122 patients with thyroid nodules with calcification. The thyroid nodules were characterized as benign or malignant by pathological diagnosis. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accordance rate of the two imaging methods were determined. The area under the receiver operating characteristics curve (AUC) was used to assess the diagnostic values of the two imaging methods. In 122 cases of thyroid nodules with calcification, 73 benign nodules and 49 malignant nodules were verified by pathological diagnosis. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accordance rate of conventional ultrasound were 50%, 77%, 59%, 69%, and 66%, respectively, and those of CEUS were 90%, 92%, 88%, 93%, and 91%, respectively. There were significant differences between the two imaging methods. AUCs of conventional ultrasound and CEUS were 0.628 ± 0.052 and 0.908 ± 0.031, suggesting low and high diagnostic values, respectively. CEUS has high diagnostic values, being significantly greater than those of conventional ultrasound, in differential diagnosis of benign and malignant thyroid nodules with calcification.

Clinical characteristics and surgical resection of multifocal papillary thyroid carcinoma: 168 cases

PURPOSE

To investigate clinical characteristics and surgical treatment of multifocal papillary thyroid carcinoma.

METHODS

A total of 648 patients diagnosed with papillary thyroid carcinoma were enrolled, 168 with multifocal papillary thyroid carcinoma. Clinicopathological factors including gender, age at diagnosis, family history of thyroid tumor, multiplicity and bilaterality of tumor, extra-thyroidal extension, lymph node involvement and other factors were statistically compared.

RESULTS

The incidence of multifocal papillary thyroid carcinoma was 25.9% and 117 presented with bilateral thyroid gland lesions. In multifocal group, patients had a higher ratio of male subjects, family history of thyroidal tumor, neck lymph node metastasis and extra-thyroidal extension by B-ultrasound. Solitary papillary thyroid carcinoma tended to be with a higher rate of benign goiters. In multifocal group, males with neck lymphadenectasis, ≥ 3 tumor masses or bilaterality of tumors tended to present with larger tumors, a higher incidence of neck lymph node metastasis and extra-thyroidal extension. 164 cases completed the follow-up, 5 died, 1 suspected with lung metastasis and still survived, 6 underwent repeated surgery due to lymph node recurrence at 3-41 months postoperatively and 2 surgically treated with recurrent gland tumor. Overall 1-, 2-, 5-, and 10-year survival rate was 98.2%, 97.4%, 96.5% and 96.5%, respectively.

CONCLUSION

Multifocal papillary thyroid carcinoma is more malignant and highly differentiated than solitary lesions. Total thyroidectomy combined with neck dissection of central compartment could be utilized as standard treatment. Lateral nodular dissection should be considered for the patients with lymph node metastasis.

Ultrasonic features of papillary thyroid microcarcinoma and non-microcarcinoma

The present study analyzed the ultrasonic features of papillary thyroid microcarcinoma (PTMC) and papillary thyroid non-microcarcinoma (non-PTMC) with the aim of improving the diagnostic value of ultrasonography. The ultrasonic features of 328 patients with papillary thyroid carcinoma (PTC), as confirmed by pathology, were retrospectively analyzed. Patients were diagnosed with PTMC if the tumor size was ≤10 mm in diameter or non-PTMC if the tumor size was >10 mm in diameter. The shape, ratio of length/width, boundary, echo, peripheral halo ring, calcification, cystic changes, blood flow, lymph node metastasis and additional accompanying thyroid diseases were compared between the patients with PTMC and non-PTMC. In total, 389 nodules were identified in the 328 patients, including 209 PTMC nodules and 180 non-PTMC nodules. The multifocality rate was 15.9% (52/328). Ultrasound scans detected a total of 371 nodules, while 18 PMTC nodules were missed diagnosed and 57 nodules were misdiagnosed as benign nodules. Statistically significant differences in the boundary, ratio of length/width, cystic changes, blood flow and lymph node metastasis were observed between the PTMC and non-PTMC groups (P<0.05). However, no statistically significant differences were observed with regard to the shape, calcification, peripheral halo rings and additional accompanying thyroid diseases between the two groups (P>0.05). Therefore, ultrasound plays an important role in the diagnosis of PTC, with PTMC and non-PTMC exhibiting different ultrasonic performances.

Prognostic significance of tumor multifocality in papillary thyroid carcinoma and its relationship with primary tumor size: a retrospective study of 2,309 consecutive patients

BACKGROUND

Tumor multifocality is frequently observed in papillary thyroid carcinoma (PTC), but its prognostic value is controversial. We investigated the prognostic significance of multifocality in PTCs larger than 1 cm and papillary thyroid microcarcinomas (PTMC).

METHODS

Medical records and pathologic results of 2,309 patients who received thyroidectomy and lymph node dissection for PTC were retrospectively reviewed. We identified 648 patients who had PTC with a primary tumor exceeding 1 cm, and 1,661 patients with PTMC. In each group, we compared patients with unifocal and multifocal disease. Cox regression analyses of disease persistence and recurrence were performed to identify the prognostic significance of multifocality.

RESULTS

The mean follow-up period was 5.6 years. In the analyses of PTCs larger than 1 cm, the multifocal group included more extensive thyroid surgeries (p = 0.039), radioactive iodine therapies with higher doses (p < 0.001), and significantly higher rates of disease persistence and recurrence (p = 0.001) compared with the unifocal group. In analogous analyses of patients with PTMC, disease persistence and recurrence did not differ significantly between the unifocal and multifocal groups. Cox regression analyses indicated that multifocality was an independent risk factor for disease persistence and recurrence in patients who had PTC with a tumor exceeding 1 cm, but not in patients with PTMC.

CONCLUSION

Tumor multifocality appears to be an important prognostic factor for PTCs larger than 1 cm, but may have little or no prognostic significance for PTMC.

Characteristic tumor growth patterns as novel histomorphologic predictors for lymph node metastasis in papillary thyroid carcinoma

The aim of this study was to investigate the efficaciousness of histological tumor growth patterns in the prediction of lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC). All combinations of infiltrative tumor border, lateral tubular growth, and intraglandular dissemination were assessed for their ability to predict LNM in 229 patients. In addition, we analyzed their predictive value within subgroups based on the tumor size and number of tumor nodules. Each tumor growth pattern was significantly associated with LNM, as 11 of the 12 combinations of these 3 patterns were found to be independently predictive of LNM (P < .05). Similar results were observed in both univariate and multivariate logistic regression analyses of PTCs, grouped according to the tumor size and number of tumor nodules. This study has shown that histological features suggestive of invasive tumor growth, including infiltrative tumor border and lateral tubular growth, may be used as independent predictive factors of LNM in PTC, and can improve treatment and follow-up strategies for PTC.

Topographic Distribution of Papillary Thyroid Carcinoma by Mapping in Coronal Sections of 125 Consecutive Thyroidectomy Specimens

INTRODUCTION

Mapping of different foci in multifocal papillary thyroid carcinoma (PTC) has previously not been done as it is difficult to do so when thyroid specimens are serially sectioned transversely (ie, parallel to the horizontal plane). In this study, thyroidectomy specimens were serially sectioned coronally (ie, parallel to the largest surface of the thyroid gland), which allows for panoramic and 3-dimensional visualization of PTC foci and their relationship to one another.

MATERIALS AND METHODS

A total of 125 consecutive total thyroidectomies or lobectomies followed by completion thyroidectomies were serially sectioned coronally and reviewed with identification and characterization of PTC foci. PTCs were grouped into either discrete, encapsulated nodule(s) (EN) of both follicular or papillary architecture, usual variant (UV), or tall cell variant (TCV).

RESULTS

The predominant tumor masses were identified in the right lobe, isthmus, and left lobe in 52%, 8%, and 40%, respectively. The largest tumor nodules ranged from 3 to 60 mm (18.8 ± 6.6) with the UV, EN, and TCV groups accounting for 58%, 24%, and 18% of cases, respectively. Three topographic patterns of PTC can be distinguished as follows: (a) single tumor nodule (37 cases), (b) main tumor nodule with satellite nodule(s) displaying no or varying degrees of fusion with the main one (30 cases), and (c) main tumor nodule with either a second large nodule or randomly occurring tumor nodules (58 cases). Bilaterality can be seen in all 3 patterns but was most prevalent in the group comprising the main tumor nodule with either a second large nodule or random tumor nodules. It was least frequent in the EN group without random tumor nodules. The difference in rates of bilaterality between tumors <10 mm and ≥10 mm was statistically significant (P < .01). For all 3 groups, satellite nodules displayed histopathological features that were similar or dissimilar to the main tumor mass. They may be of a different variant than that of the main tumor nodule.

CONCLUSIONS

With panaromic and 3-dimensional visualization, individual tumors/satellite or random nodules of multifocal PTC were readily identified in serial coronal sections of thyroidectomy specimens. Bilaterality was frequently observed in tumors associated with random PTC foci, whereas, the EN group tended to be unilateral and was not associated with random foci.

Papillary thyroid microcarcinoma with fatal outcome: evidence of tumor progression in lymph node metastases: report of 3 cases, with morphological and molecular analysis

Papillary thyroid microcarcinoma generally carries an excellent prognosis, and fatal cases are becoming increasingly rare. Their pathologic and molecular features, however, remain largely unknown. We describe 3 cases of papillary thyroid microcarcinoma that, despite surgical and radioiodine treatment, recurred, metastasized, and eventually caused the death of the patients. In addition to morphology, immunohistochemical (cyclin D1 and p53) and molecular analyses (BRAF [v-raf Murine sarcoma viral oncogene homolog B1], KRAS [V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog], HRAS [v-Ha-ras Harvey rat sarcoma viral oncogene homolog], NRAS [neuroblastoma RAS viral oncogene homolog], and PIK3CA [phosphoinositide-3-kinase, catalytic, alpha polypeptide]) were performed. Interestingly, all 3 cases presented with massive lymph node metastases that showed morphological evidence of "tumor progression" (tall cell features, poorly differentiated areas, and high-grade cytologic features). Cyclin D1 was consistently immunoreactive in both primary and metastatic site, whereas p53 was negative. BRAF V600E was absent in both sites, and KRAS, HRAS, NRAS, and PIK3CA were consistently wild type. These data suggest that, in cases of metastatic papillary thyroid microcarcinoma, an accurate morphologic analysis of the metastatic deposits could contribute to a more accurate prediction of tumor behavior.

Prognosis of multifocal papillary thyroid carcinoma

This study was to investigate the clinical features and therapeutic outcomes of multifocal papillary thyroid microcarcinoma (PTMC). A total of 2,418 papillary thyroid carcinoma (PTC) patients had undergone thyroidectomy in one medical center between 1977 and 2010. There were 483 (20.0%) diagnosed with multifocal PTC. The percentage of multifocal PTC was higher in PTMC patients (22.0%) than in non-PTMC patients (19.5%). Demographic and clinical characteristics of PTMC and multifocal PTC in PTC patients were traced. Multifocal PTC patients presented with smaller tumors at an older age, and a higher percentage underwent total or complete thyroidectomy. These patients also showed a higher incidence of postoperative disease progression than did unifocal PTC patients. Comparison of 483 patients with multifocal PTMC and non-PTMC tumors showed a higher incidence of postoperative disease progression in patients with non-PTMC; otherwise, there was no statistical difference in disease-specific and total mortality between these two groups. In conclusion, the incidence of multifocal PTMC was not lower than that of non-PTMC, and postoperative therapies were necessary for both multifocal PTMC and non-PTMC patients.