Completion thyroidectomy may not be required for papillary thyroid carcinoma with multifocality, lymphovascular invasion, extrathyroidal extension to the strap muscles, or five or more central lymph node micrometastasis

Histologic parameters driving completion thyroidectomy for papillary thyroid carcinoma in a high-volume institution: A retrospective observational study

BACKGROUND

When the histological examination indicates papillary thyroid carcinoma (PTC), there is no unanimity on the need to proceed with completion thyroidectomy (CT). This study aims to assess the histologic parameters that influenced the decision to perform CT.

MATERIALS AND METHODS

This study included PTC patients who underwent thyroid lobectomy between 2019 and 2022. Group A included patients who underwent thyroid lobectomy without further treatments, whereas Group B included those who underwent CT based on histological findings. Differences in terms of histologic parameters were analyzed.

RESULTS

Group A included 291 patients (68.3 ​%), whereas Group B 135 patients (31.7 ​%). Multivariate analysis identified associations between CT and tumor size (p ​< ​0.001), aggressive variant (p ​= ​0.009), and vascular invasion (p ​< ​0.001). ROC curve analysis established a tumor size cut-off of 21 ​mm for CT. At ROC curve analysis, the cut-off number of aggressive factors required for CT was 2.

CONCLUSION

A thorough comprehensive assessment encompassing all pathological characteristics might be necessary in case of PTC with aggressive histologic features after thyroid lobectomy.

Clinical Significance of Gross Extrathyroidal Extension to Only the Strap Muscle According to Tumor Size in Differentiated Thyroid Cancer: A Systematic Review and Meta-Analysis

OBJECTIVES

The presence of extrathyroidal extension (ETE) in patients with differentiated thyroid cancer (DTC) serves as a significant prognostic indicator. Consequently, the staging of DTC is categorized into extensive ETE and gross ETE that solely impacts the strap muscles (gross strap muscle invasion [gSMI]). However, there is a lack of sufficient evidence concerning the relationship between gSMI and prognosis, particularly in terms of tumor size.

METHODS

Relevant literature was searched in Medline, Embase, Cochrane Library, and KoreaMed. All procedures were conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and carried out by two independent reviewers. The meta-analysis utilized a random-effects model to account for the diversity of the studies. Risk of Bias for Nonrandomized Studies (RoBANS) version 2.0, an evaluation tool for non-randomized studies, was employed to assess the quality of the selected research. Clinical data from observational studies that examined the relationship between the degree of ETE and prognosis were gathered, and a meta-analysis was conducted.

RESULTS

Eighteen observational studies were included in this analysis. Subgroup analyses were conducted for each outcome. The findings revealed that the recurrence rate (odds ratio [OR], 2.498), disease-specific mortality (risk ratio [RR], 2.984), overall mortality (RR, 1.361), and lymph node (LN) metastasis (OR, 5.355) were significantly higher in patients with gSMI than in those without ETE. However, when the analysis was restricted to tumors measuring 4 cm or smaller, no significant differences in prognostic outcomes were observed, with the exception of LN metastasis.

CONCLUSION

gSMI negatively impacts prognosis; however, this correlation diminishes with smaller tumor sizes. Thus, a more cautious approach is warranted during the treatment process.

Lobectomy in patients with differentiated thyroid cancer: experience of a Chilean tertiary center

PURPOSE

Thyroid lobectomy (TL) is an appropriate treatment for up to 4 cm intrathyroidal differentiated thyroid cancer (DTC). There is scarce data regarding TL outside first-world centers. Our aim is to report a cohort of patients with DTC treated with TL in Chile.

METHODS

We included DTC patients treated with TL, followed for at least 6 months, characterized their clinicopathological features and classified their risk of recurrence and response to treatment.

RESULTS

Eighty-two patients followed for a median of 2.3 years (0.5-7.0). Seventy-three (89%) patients had papillary, 8 (9.8%) follicular and 1 (1.2%) high-grade DTC. The risk of recurrence was low in 56 (68.3%) and intermediate in 26 (31.7%). Eight (9.8%) patients required early completion thyroidectomy and radioiodine. At last follow-up, 52 (70.3%) had excellent, 19 (25.7%) had indeterminate, and 1 (1.4%) had structural incomplete response.

CONCLUSION

In a developing country, TL is an adequate option for appropriately selected DTC patients.

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.

Controversies in the Management of Intermediate-Risk Differentiated Thyroid Cancer

BACKGROUND

Intermediate-risk thyroid cancer accounts for up to two-thirds of all cases of differentiated thyroid cancer (DTC), yet it is subject to substantial variations in risk stratification and management strategies.

METHODS

This comprehensive review examines the current controversies regarding diagnosis and management of intermediate risk DTC.

RESULTS

The evolution of risk stratification systems is discussed, highlighting limitations such as heterogeneity in patient cohorts, variability in outcome definitions, and the need for more precise risk estimation tools incorporating genetic profiles and individual risk modifiers. The role of radioactive iodine therapy in intermediate-risk DTC is examined, considering evolving evidence, conflicting study results, and the necessity for personalized treatment decisions based on risk modifiers, potential morbidity, and patient preferences. Furthermore, the shift from total thyroidectomy to lobectomy in certain intermediate-risk cases is explored, emphasizing the need for tailored surgical approaches and the impact on long-term outcomes, recurrence rates, and quality of life.

CONCLUSION

Management of intermediate-risk DTC remains controversial. This review summarizes current evidence to aid decision-making. Further research, prospective trials, and collaboration are crucial to address these complexities and personalize care for patients.

The preferred surgical choice for intermediate-risk papillary thyroid cancer: total thyroidectomy or lobectomy? A systematic review and meta-analysis

BACKGROUND

The optimal surgical approach for intermediate-risk papillary thyroid carcinoma (IR-PTC) (according to ATA definition), whether total thyroidectomy (TT) or lobectomy (LT), has remained a contentious clinical gray area for several decades. This systematic review and meta-analysis aim to provide robust evidence and address this clinical dilemma comprehensively.

MATERIALS AND METHODS

A comprehensive literature search was conducted in Pubmed, Embase, Web of Science, and the Cochrane Library from 1st January 2009 to 29th December 2023 to evaluate the impact of different surgical options (TT or LT) on patients with IR-PTC. The primary outcomes included survival, recurrence rates, and postoperative complications. I2 and sensitivity analysis was used to explore the heterogeneity.

RESULTS

A total of 8 studies involving 2984 participants were included in this meta-analysis and systematic review. The results indicated that LT was a superior choice for mitigating complications compared to TT [risk ratio (RR), 0.32; 95% CI: 0.24-0.44, P <0.01], particularly for transient complications (RR, 0.24; 95% CI: 0.08-0.65, P <0.01), such as the transient parathyroid dysfunction (RR, 0.04; 95% CI: 0.01-0.15, P <0.01). However, TT did not increase the risk of recurrent laryngeal nerve palsy (RR, 0.78; 95% CI: 0.24-2.47, P =0.67), hemorrhage/seroma (RR, 0.77; 95% CI: 0.48-1.25, P =0.30), and permanent complications (RR, 0.18; 95% CI: 0.02-1.42, P =0.10). Besides, both LT and TT presented similar effect on survival outcomes (overall survival: RR, 1.00; 95% CI: 0.97-1.03, P =0.92, disease-specific survival: RR, 0.99; 95% CI: 0.97-1.02, P =0.69, recurrence-free survival: RR, 1.00; 95% CI: 0.96-1.05, P =0.86), recurrence (RR, 1.05; 95% CI: 0.76-1.46, P =0.76).

CONCLUSION

The present meta-analysis revealed that TT did not yield improved outcomes in IR-PTC patients, but was associated with an increased incidence of temporary complications. In light of these findings, it may be advisable to consider LT as the optimal choice for IR-PTC patients.

Initial versus Staged Thyroidectomy for Differentiated Thyroid Cancer: A Retrospective Multi-Dimensional Cohort Analysis of Effectiveness and Safety

The optimal surgical approach for differentiated thyroid cancer remains controversial, with debate regarding the comparative risks of upfront total thyroidectomy versus staged completion thyroidectomy following the initial lobectomy. This study aimed to assess the complication rates associated with these two strategies and identify the optimal timing for completion thyroidectomy using a multi-dimensional analysis of four cohorts: an institutional series (n = 148), the National Surgical Quality Improvement Program (NSQIP) database (n = 39,992), the TriNetX repository (n > 30,000), and a pooled literature review (10 studies, n = 6015). Institutional data revealed higher overall complication rates with total thyroidectomy (18.3%) compared to completion thyroidectomy (6.8%), primarily due to increased temporary hypocalcemia (10% vs. 0%, p = 0.004). The NSQIP analysis demonstrated that total thyroidectomy was associated with a 72% increased risk of transient hypocalcemia (p < 0.001) and a 25% increased risk of permanent hypocalcemia (p < 0.001). TriNetX data confirmed these findings and identified obesity and concurrent neck dissection as risk factors for complications. A meta-analysis showed that total thyroidectomy increased the rates of transient (RR = 1.63) and permanent (RR = 1.23) hypocalcemia (p < 0.001). Institutional and TriNetX data suggested that performing completion thyroidectomy between 1 and 6 months after the initial lobectomy minimized permanent complication rates compared to delays beyond 6 months. In conclusion, for differentiated thyroid cancer, total thyroidectomy is associated with higher risks of transient and permanent hypocalcemia compared to staged completion thyroidectomy. However, performing completion thyroidectomy within 1-6 months of the initial lobectomy may mitigate the risk of permanent complications. These findings can inform personalized surgical decision-making for patients with differentiated thyroid cancer.

The Impact of Total Tumor Diameter on Lymph Node Metastasis and Tumor Recurrence in Papillary Thyroid Carcinomas

(1) Introduction: The impact of multifocality/bilaterality on the prognosis of papillary thyroid carcinoma (PTC) is a matter of debate. In order to clarify this debate, several studies have attempted to identify additional parameters associated with poor prognosis, including total tumor diameter (TTD), in the context of multifocal PTCs. In this context, this study was carried out to investigate the impact of TTD on tumor recurrence and lymph node metastasis (LNM) in PTCs. (2) Materials and Methods: The sample of this single-center retrospective study consisted of 706 patients diagnosed with PTC. TTD was calculated as the sum of the largest diameters of tumor foci in multifocal tumors. The resulting TTDs were grouped into TTDs ≤ 10 mm, TTDs > 10 mm, TTDs ≤ 20 mm, and TTDs > 20 mm, using 10 mm and 20 mm as cutoff values. (3) Results: There was no significant difference between multifocal papillary microcarcinomas (PTMCs) with a TTD of >10 mm and unifocal PTCs with a primary tumor diameter (PTD) of >10 mm except for advanced age and lymphovascular invasion (LVI). In addition, perineural invasion (PNI) and TTD > 10 mm were found to be significant risk factors for LNM, and PNI, TTD > 10 mm, TTD > 20 mm, and bilaterality were found to be significant risk factors for recurrence. LVI, and TTD > 10 mm were found to be independent significant predictors for recurrence, and LVI and extrathyroidal extension (ETE) were found to be independent significant predictors for LNM. (4) Conclusions: Considering TTD > 10 mm in recurrence risk categorization models and adopting a clinical approach that takes into account multifocal PTMCs with TTD > 10 mm along with unifocal PTCs with PTD > 10 mm may be more useful in terms of clinical management of the disease.

Partial Thyroidectomy With Incidental Metastatic Lymph Nodes

Importance

The need for completion thyroidectomy in patients with incidental metastatic lymph nodes after partial thyroidectomy is unclear.

Objective

To investigate the outcomes of patients with incidental metastatic lymph nodes following partial thyroidectomy.

Design, Setting, and Participants

A retrospective review of a prospectively maintained thyroid cancer database from 1985 to 2015 was carried out at a head and neck surgery practice at a tertiary referral cancer center. A total of 74 patients who underwent thyroid lobectomy or thyroid isthmusectomy between 1985 and 2015 and were found to have incidental metastatic lymph nodes on final pathologic analysis and were selected to be observed without immediate completion thyroidectomy were included. A separate group of additional 11 patients who underwent immediate completion thyroidectomy was also identified and reviewed.

Main Outcome and Measure

Analysis took place from February to May 2022. Recurrence-free survival outcomes of patients found to have incidental metastatic lymph nodes on final pathologic analysis following partial thyroidectomy with no immediate completion thyroidectomy.

Results

A total of 74 patients were observed, with a median (IQR) age of 39 (28-49) years; 44 (59%) were women. Sixty-four patients underwent thyroid lobectomy and 10 patients had isthmusectomy. Classic papillary thyroid carcinoma was the most common histologic type (34 [46%]). Vascular invasion and microscopic extrathyroidal extension were present in 11 patients (16%) and 22 patients (30%), respectively. Positive margins were identified in 5 patients (7.8%). Size of metastatic lymph nodes ranged between 0.07 cm and 1.2 cm. No extranodal extension was reported. A total of 52 patients (70%) were classified as intermediate risk for recurrence based on the American Thyroid Association risk stratification system. The median (IQR) follow up was 48.15 (15.4-86.1) months, during which only 1 patient had a regional recurrence. Another patient underwent delayed completion thyroidectomy for a contralateral lobe malignant abnormality. Recurrence-free survival, disease-specific survival, and overall survival were 97.4%, 100%, and 96.2%, respectively. A separate group of 11 patients who underwent immediate completion thyroidectomy were reviewed. These patients were more likely to have tall-cell papillary thyroid carcinoma (6 [55%] vs 13 [18%]), multifocality (9 [82%] vs 28 [41%]), microscopic extrathyroidal extension (8 [73%] vs 22 [30%]), and positive margins (3 [30%] vs 5 [7.8%]) compared with patients who were under observation only.

Conclusion and Relevance

Completion thyroidectomy may not be necessary in appropriately selected patients who are found to have incidental metastatic lymph nodes (N1a) after partial thyroidectomy for localized well-differentiated thyroid cancer.