The value of preoperative PET-CT in papillary thyroid cancer

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

Multimodal imaging of thyroid cancer

PURPOSE OF REVIEW

Thyroid cancer is the most common endocrine cancer in adults with rising incidence. Challenges in imaging thyroid cancer are twofold: distinguishing thyroid cancer from benign thyroid nodules, which occur in 50% of the population over 50 years; and correct staging of thyroid cancer to facilitate appropriate radical surgery in a single session. The clinical management of thyroid cancer patients has been covered in detail by the 2015 guidelines of the American Thyroid Association (ATA). The purpose of this review is to state the principles underlying optimal multimodal imaging of thyroid cancer and aid clinicians in avoiding important pitfalls.

RECENT FINDINGS

Recent additions to the literature include assessment of ultrasound-based scoring systems to improve selection of nodules for fine needle biopsy (FNB) and the evaluation of new radioactive tracers for imaging thyroid cancer.

SUMMARY

The mainstay of diagnosing thyroid cancer is thyroid ultrasound with ultrasound-guided FNB. Contrast-enhanced computed tomography and PET with [F]-fluorodeoxyglucose (FDG) and MRI are reserved for advanced and/or recurrent cases of differentiated thyroid cancer and anaplastic thyroid cancer, while [F]FDOPA and [Ga]DOTATOC are the preferred tracers for medullary thyroid cancer.

Carbon nanoparticles guide contralateral central neck dissection in patients with papillary thyroid cancer

The treatment of contralateral central neck lymph node metastasis is controversial in patients with papillary thyroid cancer. The present study reports the use of carbon nanoparticles (CNs) as lymph node tracers and discusses the potential role of predicting contralateral central neck metastasis is evaluated, so as to guide contralateral central neck dissection (CND). A total of 70 consecutive patients with papillary thyroid cancer were enrolled in the present study. All patients underwent a total or near-total thyroidectomy plus bilateral CND, during which CNs were used as a lymph node tracer. Of the 70 enrolled patients, 51 (72.86%) were confirmed to have lymph node metastasis in the central neck, 50 (71.43%) patients in the ipsilateral central neck and 14 (20.00%) in the contralateral central neck. A total of 579 (84.90%) lymph nodes were stained black by CNs. Of the 193 metastatic lymph nodes, 168 were located in the ipsilateral central compartment and the other 25 in the contralateral central compartment. A total of 147 (76.17%) metastatic lymph nodes were stained black. A total of 21 metastatic lymph nodes were found in the contralateral central compartment, 4 metastatic lymph nodes of contralateral central compartment were not black-stained. The sensitivity and specificity of CNs for contralateral metastasis was 84 and 25%, respectively. Contralateral central lymph node metastasis was significantly associated with extrathyroid extension and the presence of ipsilateral central neck lymph node metastasis. Together, the results of the present study reveal that CNs might accurately predict contralateral central lymph nodes metastasis and could be used to direct CND.

Correlation of BRAFV600E Mutation and Glucose Metabolism in Thyroid Cancer Patients: An ¹⁸F-FDG PET Study

There is significant interest in a better understanding of the genetic underpinnings of the increased glucose metabolic rates of cancer cells. Thyroid cancer demonstrates a broad variability of (18)F-FDG uptake as well as several well-characterized oncogenic mutations. In this study, we evaluated the differences in glucose metabolism of the BRAF(V600E) mutation versus BRAF wild-type (BRAF-WT) in patients with metastatic differentiated thyroid cancer (DTC) and poorly differentiated thyroid cancer (PDTC).

METHODS

Forty-eight DTC and 34 PDTC patients who underwent (18)F-FDG PET/CT for tumor staging were identified from a database search. All patients were tested for the BRAF(V600E) mutation and assigned to 1 of 2 groups: BRAF(V600E) mutated and BRAF-WT. (18)F-FDG uptake of tumor tissue was quantified by maximum standardized uptake value (SUVmax) of the hottest malignant lesion in 6 prespecified body regions (thyroid bed, lymph nodes, lung, bone, soft tissue, and other). When there were multiple lesions in 1 of the prespecified body regions, only the 1 with the highest (18)F-FDG uptake was analyzed.

RESULTS

In the DTC cohort, 24 tumors harbored a BRAF(V600E) mutation, whereas 24 tumors were BRAF-WT. (18)F-FDG uptake of BRAF(V600E)-positive lesions (median SUVmax, 6.3; n = 53) was significantly higher than that of BRAF-WT lesions (n = 39; median SUVmax, 4.7; P = 0.019). In the PDTC group, only 5 tumors were BRAF(V600E)-positive, and their (18)F-FDG uptake was not significantly different from the BRAF-WT tumors. There was also no significant difference between the SUVmax of all DTCs and PDTCs, regardless of BRAF mutational status (P = 0.90).

CONCLUSION

These data suggest that BRAF(V600E)-mutated DTCs are significantly more (18)F-FDG-avid than BRAF-WT tumors. The effect of BRAF(V600E) on tumor glucose metabolism in PDTC needs further study in larger groups of patients.

Thyroid atypia of undetermined significance or follicular lesion of undetermined significance: an indispensable Bethesda 2010 diagnostic category or waste garbage?

OBJECTIVE

The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) was introduced in thyroid cytology in 2007 and is now generally accepted. BSRTC categories include a morphologic description and risk of malignancy as well as follow-up suggestions in each group. However, the category entitled 'atypia of undetermined significance or follicular lesion of undetermined significance' (AUS/FLUS) is problematic. This category is heterogeneous and has been overused so far.

STUDY DESIGN

Twenty-six studies were included in a meta-analysis. In addition to AUS/FLUS percentage, we analysed repeated AUS/FLUS percentage, cytological and histological correlations, and risk of malignancy and neoplasm for AUS/FLUS. Furthermore, stratification, inter- and intra-observer variability, and the possibility of a switch to another category and its clinical consequences were reviewed.

RESULTS

Out of a total of 81,833 cases, AUS/FLUS accounted for 10.9%, with a 34% risk of malignancy. Persistent AUS/FLUS was found in 21.6% in repeated cytology. Cytohistological correlation was analysed from 16 studies (4,964 cases), revealing 10.4% as AUS/FLUS and a 21.5% risk of malignancy.

CONCLUSIONS

An AUS/FLUS category seems to be currently reasonable with clearly defined cytomorphological criteria which do not correspond unequivocally with those of the other categories. An AUS/FLUS category is justified and possible means of its improvement with immunohistochemistry, molecular analysis and imaging are discussed.

The pros and cons of prophylactic central neck dissection in papillary thyroid carcinoma

Prophylactic central neck dissection (pCND) for management of papillary thyroid carcinoma (PTC) is controversial. Compared to many malignancies, PTC has a high overall survival but local recurrence due to lymph node metastases continue to present management challenges. Unlike lateral cervical nodal metastasis metastasis, central neck nodal metastasis are unable to be reliably detected clinically or radiologically at pre-operative assessment. Residual disease (recurrent or persistent) typically requires re-operative surgery in the central compartment, which carries a heightened risk of significant morbidity. These nodal groups can be accessed during the index thyroidectomy for PTC. Thus, pCND offers potential to reduce the rates of recurrence and the need for re-operative surgery in the central neck. This benefit needs to be balanced with the potential morbidity risk from pCND itself at the index resection. This review will discuss the advantages and disadvantages of pCND with regard to long-term outcomes and potential morbidity. The rationale of pCND will be discussed, along with the indications for ipsilateral and contralateral pCND, the role of re-operative surgery for recurrence and the use of selective versus routine pCND. Strategies to select higher risk patients for pCND with the use of molecular markers will be addressed, along with a discussion of quality of life (QoL) research in PTC.