Current evidences in poorly differentiated thyroid carcinoma: a systematic review and subsection meta-analysis for clinical decision making.

BACKGROUND: Poorly differentiated thyroid carcinoma (PDTC) is a distinct entity with intermediate prognosis between indolent follicular thyroid cancers and anaplastic carcinoma. The management guidelines are not standardized for these cancers due its low prevalence and limited available literature. Therefore, we did this systematic review with emphasis on current evidence on diagnosis, imaging, molecular markers, and management of these carcinomas. MATERIALS AND METHODS: We searched four databases, PubMed, Medline, EMBASE, and Emcare to identify studies published till October 2023. All studies reporting diagnostic tests, imaging, molecular marker expression and management of PDTC were included in the review. The meta-analysis was conducted on expression of molecular markers in these cancers following recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Random-effects meta-analysis was used to calculate pooled estimated prevalence with 95% confidence intervals. Based on the inclusion criteria, 62 articles were selected to be incorporated for the review. Differences in pathological diagnostic criteria of PDTC was noted in literature which was addressed in WHO 2022 diagnostic terminologies with expansion of the definition. Surgical management is uniformly recommended for early stage PDTC. However, literature is divided and anecdotal for recommendations on radioactive iodine (RAI), extent of neck dissection and adjuvant treatment in PDTC. Evidence for Next Generation Sequencing (NGS), novel theragnostic approaches, immunotherapy targets are evolving. Based on the subset analysis for expression of molecular markers, we found the most common markers expressed were TERT (41%), BRAF (28%) and P 53 (25%). CONCLUSION: Poorly differentiated thyroid carcinomas have a high case fatality rate (up to 31%). Eighty-five % of the patients who succumb to the disease have distant metastasis. Even though under-represented in literature, evidence-based management of these aggressive tumors can help personalize the treatment for optimal outcomes.

Lenvatinib as a Promising Treatment Option for Unresectable Hürthle Cell Carcinoma: A Case Report.

Hürthle cell carcinoma (HCC) of the thyroid gland generally has a more aggressive clinical course than other differentiated thyroid cancers (DTCs), and it is associated with a higher rate of distant metastases. In this case report, we highlight the importance of tyrosine kinase inhibitors as a management strategy for unresectable DTCs. Surgical management is challenging if the cancer is locally advanced and invades major neck structures with an increased risk of recurrence. Tyrosine kinase inhibitors (TKIs) are used in the case of advanced disease, especially in unresectable, radio-iodine refractory and with metastatic status. Lenvatinib, a TKI, used as the first line of treatment, plays a key role in improving prognosis and survival rates among patients. A 37-year-old gentleman presented with a locally advanced and widely metastasized case of large Hürthle cell carcinoma encasing the left carotid sheath and the left recurrent laryngeal nerve. Fine needle aspiration cytology (FNAC) was suggestive of HCC and a positron emission tomography-computed tomography (PET-CT) scan revealed metastases to the lungs and spine. In this case, lenvatinib was used to prevent the proliferation of malignant cells and the neovascularization of the tumor. This clinically translated into a good response in a high disease burden scenario. The patient showed positive results with lenvatinib therapy with a progression-free duration of 30 months and a reduction in the size of cancer. This case report describes the use of lenvatinib for the treatment of a large unresectable locally advanced and widely metastasized case of Hürthle cell carcinoma in a young gentleman with a response profile.