Differentiated thyroid carcinoma in children: A retrospective analysis of 125 pediatric cases from a single institution in India

The Definition of Recurrence of Differentiated Thyroid Cancer: A Systematic Review of the Literature

Background: Recurrence is a key outcome to evaluate the treatment effect of differentiated thyroid carcinoma (DTC). However, no consistent definition of recurrence is available in current literature or international guidelines. Therefore, the primary aim of this systematic review was to delineate the definitions of recurrence of DTC, categorized by total thyroidectomy with radioactive iodine ablation (RAI), total thyroidectomy without RAI and lobectomy, to assess if there is a generally accepted definition among these categories. Methods: This study adhered to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. In December 2023, a systematic literature search in MEDLINE and EMBASE was performed for studies reporting on the recurrence of DTC, from January 2018 to December 2023. Studies that did not provide a definition were excluded. Primary outcome was the definition of recurrence of DTC. Secondary outcome was whether studies differentiated between recurrence and persistent disease. Two independent investigators screened the titles and abstracts, followed by full-text assessment and data extraction. The study protocol was registered in PROSPERO, CRD42021291753. Results: In total, 1450 studies were identified. Seventy studies met the inclusion criteria, including 69 retrospective studies and 1 randomised controlled trial (RCT). Median number of patients in the included studies was 438 (range 25-2297). In total, 17 studies (24.3%) reported on lobectomy, 4 studies (5.7%) on total thyroidectomy without RAI, and 49 studies (70.0%) with RAI. All studies defined recurrence using one or a combination of four diagnostic modalities cytology/pathology, imaging studies, thyroglobulin (-antibodies), and a predetermined minimum tumor-free time span. The most common definition of recurrence following lobectomy was cytology/pathology-proven recurrence (47.1% of this subgroup), following total thyroidectomy with RAI was cytology/pathology-proven recurrence and/or anomalies detected on imaging studies (22.4% of this subgroup). No consistent definition was found following total thyroidectomy without RAI. Nine studies (12.9%) differentiated between recurrence and persistent disease. Conclusion: Our main finding is that there is no universally accepted definition for recurrence of DTC in the current studies across any of the treatment categories. The findings of this study will provide the basis for a future, international Delphi-based proposal to establish a universally accepted definition of recurrence of DTC. A uniform definition could facilitate global discussion and enhance the assessment of treatment outcomes regarding recurrence of DTC.

Radioactive iodine ablation therapy reduces the risk of recurrent disease in pediatric differentiated thyroid carcinoma

BACKGROUND

While radioactive iodine (RAI) therapy in older adults with differentiated thyroid carcinoma (DTC) reduces recurrence, data in pediatrics remain limited. We conducted a meta-analysis to quantify outcomes and recurrence risk with RAI versus thyroidectomy alone in the pediatric population.

METHODS

Systematic literature review identified 34 retrospective studies including 2913 DTC patients under age 22 years (published 2005-2023). Meta-analysis calculated pooled rates of disease persistence and recurrence. Relative risk ratios compared odds of recurrence with RAI versus no RAI.

RESULTS

Patients had mean age 14.7 years (95 % CI, 14.2-15.2) and were 75.9 % female (95 % CI, 73.8-78.1 %). Majority (90.2 %) received RAI. Pooled persistence rate was 30.3 % (95 % CI, 21.7-39.5 %); higher with RAI (31.5 %; 95 % CI, 22.4-41.3 %) than no RAI (4.5 %; 95 % CI, 0.0-18.7 %) (OR 3.28; 95 % CI,1.82-5.91; p < 0.001). Recurrence rate was 8.97 % (95 % CI, 4.78-14.3 %). Those with RAI had 53.1 % lower recurrence risk versus no RAI (RR 0.47; 95 % CI, 0.27-0.82; p = 0.007). Median follow-up was 7.2 years (95 % CI, 5.8-8.5 years), with no association between follow-up duration and recurrence (r = -0.053; p = 0.80).

CONCLUSIONS

RAI therapy as an adjunct to thyroidectomy is associated with a significantly lower risk of long-term recurrence in pediatric DTC. These findings advocate for the use of RAI in preventing recurrence among high-risk pediatric patients with DTC.

Recurrence and survival for patients with thyroid carcinoma in the pediatric age group in the Emirate of Abu Dhabi: retrospective analysis of a multicentre cohort

OBJECTIVES

Pediatric thyroid cancer represents 2.3 % of thyroid cancers, and its long-term outcome data are sparse. There have not been studies in the UAE delineating its epidemiology, clinical and histological characteristics, and follow-up outcomes. We aimed to evaluate the clinical-pathological behavior, recurrence and survival rates in pediatrics with all types of thyroid cancer in the UAE.

METHODS

Multicentre retrospective chart review analysis of pediatric patients with thyroid carcinoma from January 2010 to December 2020 in Abu Dhabi, UAE.

RESULTS

Thirty-four patients were included, 85 % being females. Papillary thyroid carcinoma (PTC) was the commonest type of thyroid cancer (88 %) vs. follicular thyroid carcinoma (FTC) (11.8 %). Almost half of our patients had a multifocal disease, 26 % had lymphovascular invasion (LVI), and 21 % had extrathyroidal extension (ETE). There were no mortalities during follow-up. 85 % of patients exhibited complete remission, while 15 % of patients showed evidence of progressive residual or recurrent disease. One patient had metastasis to lymph nodes and lungs.

CONCLUSIONS

There were similar trends of incidence, sex prevalence, and histopathological patterns as the ones observed internationally. Potential risk factors in our population include a family history of thyroid cancer and obesity. The lower rate of ETE, LVI, metastasis, and recurrence indicates a possibly less aggressive disease.

Survival Trends in Pediatric Differentiated Thyroid Cancer: A Middle Eastern Perspective

Pediatric Differentiated Thyroid Cancer (pedDTC) is a rare pediatric malignancy with an increasing incidence over time. To date, there is a paucity of literature specifically addressing pedDTC within the context of Middle Eastern ethnicity. This retrospective study aimed to assess the risk-stratifying factors for overall survival (OS) and event-free survival (EFS) in pediatric DTC patients from Iraq and Jordan. The medical records of 81 patients from two tertiary cancer institutes were retrieved. Kaplan-Meier analysis was employed to investigate OS and EFS, and the Cox proportional hazards model was employed to estimate hazard ratios. All patients underwent surgery and radioactive iodine therapy, with a median age of 14 and an interquartile range of 12-15. Lymph node involvement was observed in 55% of cases, while distant metastases were present in 13.5%. After a median follow-up period of 68 months, the 10-year survival rate was determined to be 94%, while the 10-year EFS rate was 58%. EFS was negatively impacted by cervical lymph node metastases and early age of diagnosis (p ≤ 0.01, each). Therefore, pediatrics with initial cervical lymph node metastases and those diagnosed before puberty tend to experience poorer EFS, which may justify the need for more aggressive management plans.

Strategies for Radioiodine Treatment: What’s New

Radioiodine treatment (RAI) represents the most widespread and effective therapy for differentiated thyroid cancer (DTC). RAI goals encompass ablative (destruction of thyroid remnants, to enhance thyroglobulin predictive value), adjuvant (destruction of microscopic disease to reduce recurrences), and therapeutic (in case of macroscopic iodine avid lesions) purposes, but its use has evolved over time. Randomized trial results have enabled the refinement of RAI indications, moving from a standardized practice to a tailored approach. In most cases, low-risk patients may safely avoid RAI, but where necessary, a simplified protocol, based on lower iodine activities and human recombinant TSH preparation, proved to be just as effective, reducing overtreatment or useless impairment of quality of life. In pediatric DTC, RAI treatments may allow tumor healing even at the advanced stages. Finally, new challenges have arisen with the advancement in redifferentiation protocols, through which RAI still represents a leading therapy, even in former iodine refractory cases. RAI therapy is usually well-tolerated at low activities rates, but some concerns exist concerning higher cumulative doses and long-term outcomes. Despite these achievements, several issues still need to be addressed in terms of RAI indications and protocols, heading toward the RAI strategy of the future.

A ceRNA network mediated by LINC00475 in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most frequent histological type of differentiated thyroid carcinoma. Long noncoding RNAs (lncRNAs) have been widely reported to play a key role in human malignancies, and PTC is included. This study aimed to find out the functions and mechanism of lncRNA LINC00475 in PTC. LINC00475 was upregulated in PTC cells and was mainly located in the cytoplasm according to reverse-transcription polymerase chain reaction analyses and subcellular fractionation assays. As shown by cell counting kit-8 assays, ethynyl deoxyuridine incorporation assays, wound healing assays, and transwell assays, LINC00475 knockdown suppressed cell viability, proliferation, migration, and invasion. Mechanistically, LINC00475 upregulated the expression of messenger RNA zinc finger CCHC-type containing 12 (ZCCHC12) by binding to miR-376c-3p. ZCCHC12 was a direct target gene of miR-376c-3p in PTC cells. The relationship between miR-376c-3p and LINC00475 (or ZCCHC12) in PTC cells was probed by luciferase reporter assays, RNA pulldown assays, and RNA immunoprecipitation assays. In addition, both mRNA and protein levels of ZCCHC12 were downregulated due to miR-376c-3p overexpression or LINC00475 silencing. ZCCHC12 overexpression partially reversed the suppressive effect of LINC00475 knockdown on malignant behaviors of PTC cells. In conclusion, LINC00475 promotes PTC cell proliferation, migration, and invasion by upregulating ZCCHC12 via the interaction with miR-376c-3p.