Papillary Thyroid Micro Carcinoma: The Incidence of High-Risk Features and Its Prognostic Implications

Is conservative treatment always safe in unifocal clinically T1a/node-negative papillary thyroid carcinoma?

BACKGROUND

Management of clinically unifocal node-negative papillary thyroid carcinoma ≤1 cm (PTMC) is controversial with nonsurgical treatment as a potential alternative to thyroid lobectomy (TL). However, conservative strategies, such as active surveillance or thermal ablation, do not allow the evaluation of biological aggressive features or occult lymph node metastases (LNMs), which play a primary role as prognostic factors.

METHODS

Among 4216 thyroidectomies for malignancy (between September 2014 and September 2023), TL plus ipsilateral central neck dissection was performed in 203 (4.8%) unifocal N0 PTMCs. Completion thyroidectomy was accomplished in case of positive frozen section examination of removed nodes or within 6 months from index operation in presence of biological aggressive features.

RESULTS

Seventy-six out of 203 (37.4%) patients were staged pN1a and extranodal extension was detected in 5 (6.6%) patients. At final histology, biological aggressive features, including multifocality, lymphovascular invasion (LVI), extracapsular invasion, tumor aggressive subtypes, and BRAF-V600E mutation, were detected in 69 (34%), 93 (45.8%), 3 (1.5%), 30 (14.8%), and 7 (3.5%) patients, respectively. A comparative analysis between pN0 and pN1a patients showed younger age (p < 0.001), LVI (p = 0.037), and multifocality (p < 0.001) as risk factors for occult central LNMs. After logistic regression analysis, age (p < 0.001) and multifocality (p < 0.001) were confirmed as independent risk factors for nodal involvement.

CONCLUSIONS

Although most PTMC has been widely defined as indolent disease, a non-negligible rate of patients may present one or more biologically aggressive features including nodal involvement. Nonsurgical management should be considered with caution to avoid undertreatment especially in the younger population.

Comparison of the value of ultrasound-guided fine needle aspiration biopsy and contrast-enhanced ultrasound in different sizes of thyroid nodules

The purpose of this study was to evaluate the diagnostic value of ultrasound-guided fine needle aspiration biopsy (US-FNAB) and contrast-enhanced ultrasound (CEUS) in the presence of thyroid nodules of different sizes. We retrospectively analyzed 110 patients with surgically operated unimodular thyroid nodules in Yichang City Central Hospital from July 1, 2021, to April 1, 2023, all of whom underwent conventional thyroid ultrasound, CEUS, and US-FNAB, and all of whom were classified according to the size of nodules into <0.5, 0.5 to 1, and ≥1 cm groups. The diagnostic accuracy, sensitivity, and specificity of the 2 methods for benign and malignant nodules were calculated. Among 110 thyroid nodules, 102 were malignant nodules and 8 were benign nodules. In patients with nodule diameters <1 cm the sensitivity of US-FNAB and CEUS was 87.02% and 93.89%, respectively, and the specificity was 100.00% and 66.67%, with an accuracy of 87.31% and 93.28%, respectively. In patients with nodule diameter <0.5 cm, the sensitivities of US-FNAB and CEUS were 74.29% and 100.00%, respectively, and the differences were statistically significant (P < 0.05); in patients with nodule diameter 0.5 to 1 cm, the sensitivities of US-FNAB and CEUS were 79.59% and 95.92%, respectively, and the differences were statistically significant (P < 0.05); among patients with nodule diameters ≥1 cm, the sensitivities of US-FNAB and CEUS were 88.89% and 77.78%, respectively, with no statistically significant difference (P > 0.05). For thyroid nodules ≤1 cm in diameter, the sensitivity of CEUS examination was higher than that of US-FNAB; and CEUS still has good diagnostic accuracy in the diagnosis of benign and malignant thyroid nodules <0.5 cm, CEUS is recommended for thyroid nodules diagnosed negatively by US-FNAB with a diameter of <1 cm; and CEUS should be preferred for thyroid nodules with a diameter of <0.5 cm. CEUS should be preferred for thyroid nodules <0.5 cm in diameter.

Incidental thyroid carcinoma in an endemic goiter area in Italy: histopathological features and predictors of a common finding

PURPOSE

The occurrence and histopathological features of incidental thyroid carcinoma (ITC) vary considerably among populations from different geographical regions. The aim of this study is to assess the prevalence and histopathological characteristics of ITC in patients who underwent thyroid surgery for apparently benign thyroid diseases in an endemic goiter area in Italy.

METHODS

A total of 649 consecutive patients (531 females and 118 males; mean age, 52.9 ± 11.0 years), who underwent thyroid surgery at the Endocrine Surgery Unit of the tertiary care "Renato Dulbecco" University Hospital (Catanzaro, Italy) in the period between years 2017 and 2022, were included in this retrospective study. A comprehensive histopathological examination was performed on surgically excised thyroid tissue. Logistic regression analysis was employed to identify potential predictors of ITC.

RESULTS

The histopathological examination revealed the presence of ITC in 81 patients, accounting for 12.5% of the total study population. The female to male ratio was found to be 6.4 to 1. Among the patients with ITC, 72 had papillary carcinoma (PTC), with 53 of these tumors being microcarcinomas (microPTC). Additionally, 5 patients had follicular thyroid carcinoma, 2 patients had low-risk follicular cell-derived thyroid neoplasms, 1 patient had an oncocytic carcinoma, and 1 patient had a medullary thyroid carcinoma. Logistic regression analysis demonstrated a significant association between female sex and incidental microPTC.

CONCLUSIONS

These findings provide further evidence of the common occurrence of ITC, typically in the form of microPTC, among individuals who undergo thyroid surgery for apparently benign thyroid diseases.

A clinical and molecular pathology prediction model for central lymph node metastasis in cN0 papillary thyroid microcarcinoma

BACKGROUND

The frequency of thyroid cancer has rapidly increased in recent years globally. Thus, more papillary thyroid microcarcinoma (PTMC) patients are being diagnosed, including clinical lymph node-negative (cN0) patients. Our study attempted to develop a prediction model for assessing the probability of central lymph node metastasis (CLNM) in cN0 PTMC patients.

METHODS

A total of 595 patients from the Affiliated Hospital of Qingdao University (training cohort: 456 patients) and the Affiliated Hospital of Jining Medical University (verification cohort: 139 patients) who underwent thyroid surgery between January 2020 and May 2022 were enrolled in this study. Their clinical and molecular pathology data were analyzed with multivariate logistic regression to identify independent factors, and then we established a prediction model to assess the risk of CLNM in cN0 PTMC patients.

RESULTS

Multivariate logistic regression analysis revealed that sex, Hashimoto's thyroiditis (HT), tumor size, extrathyroidal extension, TERT promoter mutations and NRAS mutation were independent factors of CLNM. The prediction model demonstrated good discrimination ability (C-index: 0.757 and 0.753 in the derivation and validation cohorts, respectively). The calibration curve of the model was near the optimum diagonal line, and decision curve analysis (DCA) showed a noticeably better benefit.

CONCLUSION

CLNM in cN0 PTMC patients is associated with male sex, tumor size, extrathyroidal extension, HT, TERT promoter mutations and NRAS mutation. The prediction model exhibits good discrimination, calibration and clinical usefulness. This model will help to assess CLNM risk and make clinical decisions in cN0 PTMC patients.

The efficacy and safety of microwave ablation versus conventional open surgery for the treatment of papillary thyroid microcarcinoma: a systematic review and meta-analysis

Background

Microwave ablation (MWA) technology has been applied to the treatment of papillary thyroid microcarcinoma (PTMC); however, its use as an alternative to conventional open surgery (OS) remains controversial, because it belongs to non-tumor radical treatment. Our article sought to compare the efficacy and safety of MWA and OS in the treatment of PTMC.

Methods

We searched seven databases for studies evaluating the treatment of patients with PTMC using MWA as intervention group and OS as control group, the main outcome contained intra-operative, post-operative and follow-up outcomes. Review Manager 5.4 was used to estimate the effects of the results of the included articles and Cochrane Risk of Bias 2.0 was used to assess the risk of bias. The data were pooled to calculate the mean differences (MD) with 95% confidence intervals (CIs) for the continuous data and the odds ratio (OR) with 95% CIs for the dichotomous data.

Results

A total of 13 studies, comprising 1,088 and 1,081 patients in the MWA and OS groups, respectively, were identified that compared the results of MWA to OS in the treatment of PTMC. All of the articles were at low risk of bias. There were no differences in terms of the recurrence rate (OR =0.80, 95% CI: 0.37 to 1.77; P=0.59) or lymph node metastasis (OR =0.71, 95% CI: 0.26 to 1.95; P=0.51) between the 2 groups. However, compared to the OS group, the MWA group had a shorter operation time (MD =-44.85, 95% CI: 5.73 to 20.68; P<0.00001), less intra-operative blood loss (MD =-23.37, 95% CI: -29.57 to -17.17; P<0.00001), a smaller surgical incision (MD =-47.04, 95% CI: -81.93 to -12.14; P=0.008), a shorter postoperative hospital stay (MD =-4.19, 95% CI: -5.46 to -2.92; P<0.00001), lower hospitalization expenses (MD =-85.65, 95% CI: -133.86 to -37.45; P<0.00001), and fewer complications (OR =0.23, 95% CI: 0.16 to 0.33; P<0.00001).

Conclusions

This meta-analysis suggests that MWA is better than OS at treating PTMC in terms of both intra-operative and post-operative outcomes. Due to the quality and number of the included studies, the long-term effects and suitability of MWA in the treatment of PTMC need to be further studied.

Lymph Node Metastases Identified at the Post-Ablation 131I SPECT/CT Scan Is a Prognostic Factor of Intermediate-Risk Papillary Thyroid Cancer

The intermediate-risk category of papillary thyroid cancer (PTC) comprises heterogeneous patients within a wide range of stages and varied care management. Understanding the risk features of recurrence observed after the initial therapy should be emphasized. We aimed to evaluate the prognostic significance of radioactive iodine-avid lymph nodes observed during the initial treatment of patients with PTC that were considered to be at intermediate risk. Data on patients with intermediate-risk PTC treated from 2012 to 2018 were retrospectively reviewed. Post-therapeutic SPECT/CT (Rx SPECT/CT) was evaluated in the enrolled patients. The clinical, pathologic, and incidence of radioiodine-avid (RAI-avid) lymph node metastasis (mLN) on Rx SPECT/CT were reviewed, and risk factors related to recurrent disease were analyzed. After a median follow-up of 37.26 (30.90, 46.33) months, structural persistent/recurrent disease was detected in 9.81% (36/367) of patients with intermediate-risk tumors. The incidence of recurrence was higher in patients who demonstrated RAI-avid mLN after the initial therapy than in those who did not (p < 0.001). In a multivariate Cox proportional hazard regression analysis, RAI-avid mLN appeared to be a robust risk factor for recurrent disease after the initial therapy (HR: 8.967, 95% CI: 3.433−23.421, p = 0.000). RAI-avid mLN is a significant risk factor for recurrent intermediate-risk PTC after the initial treatment.

Papillary thyroid microcarcinomas that metastasize to lymph nodes

PURPOSE

We aimed to determine clinicopathological features that can predict lymph node metastasis (LNM) in papillary thyroid microcarcinomas (PTMC).

METHODS

Medical records of 872 patients with papillary thyroid cancer >1 cm (PTC > 1 cm) and 1184 patients with papillary thyroid microcancer (PTMC) (≤1 cm) were reviewed retrospectively. Demographical, clinical and histopathological features of (PTC > 1 cm) and PTMC were compared. Association between clinicopathological features and LNM in PTMC was investigated.

RESULTS

The median age of patients with PTMC was significantly higher than patients with PTC > 1 cm (49 vs 46 years old, p < 0.001). Multifocality, capsular invasion, vascular invasion, extrathyroidal extension (ETE) and LNM were more frequent in patients with PTC > 1 cm compared to patients with PMTC (p < 0.001 for each). In PTMC group, those with LNM had significantly higher proportion of multifocality, capsular invasion, vascular invasion and ETE compared to those without LNM (p = 0.007, <0.001, p = 0.011 and p < 0.001, respectively). Multifocality and ETE were significant factors for LNM with logistic regression analysis. Multifocality increased the risk of LNM by 1.737 times (95% CI: 1.079-2.979) and ETE increased the risk by 3.528 times (95%: 1.914-6.503). Primary tumor diameter ≥ 5.75 mm was predictive for LNM with a sensitivity of 0.782 and a specificity of 0.517 in PTMC.

CONCLUSIONS

LNM should be investigated more carefully in patients with PTMC in the presence of tumor diameter ≥ 5.75 mm, multifocality or ETE.

Clinical Characteristics-Assisted Risk Stratification for Extent of Thyroidectomy in Patients With 1-4 cm Solitary Intrathyroidal Differentiated Thyroid Cancer

BACKGROUND

Differentiated thyroid cancer (DTC) is the most common type of thyroid cancer. The 2015 American Thyroid Association (ATA) guidelines recommend that lobectomy is suitable for solitary intrathyroidal DTC (SI-DTC) of 1-4 cm. However, some SI-DTC patients with other high-risk characteristics still have poor prognosis and require more aggressive surgical methods. This study aimed to explore the clinical characteristics that are important for the identification and treatment of high-risk patients with SI-DTC of 1-4 cm.

METHODS

The study cohort was obtained from the SEER database, consisting of data between 2004 and 2013. The outcome measures were thyroid carcinoma-specific mortality (CSM) and all-cause mortality (ACM). Patient survival curves were examined using Kaplan-Meier analyses with log-rank tests and Cox proportional hazards regression analyses. Hazard ratios (HRs) were used to show the magnitude of the effect of disease stage on DTC-specific patient mortality.

RESULTS

The study included 55,947 patients with SI-DTC of 1-4 cm and 4,765 patients with DTC >4 cm. Tumor size, surgical approach, age, sex, race, and radiation exposure were independent risk factors for CSM and ACM. SI-DTC patients with female, age ≤45, and 1 cm< tumor size ≤2 cm were at low risk of CSM [HR = 0.014 (0.002-0.115)] and ACM [HR = 0.115 (0.077-0.171)] when stratified by age, sex, and tumor size. Compared to T3 patients, CSM was not significantly different in male patients, age >45, 2 cm< tumor size ≤3 cm [HR = 0.839 (0.414-1.700)] and male patients, age >45, 1 cm< tumor size ≤2 cm [HR = 0.751 (0.410-1.377)]. Furthermore, compared to T3 patients without extrathyroidal extension (ETE) and lymph node metastasis (LNM), more subgroups of SI-DTC of 1-4 cm had a similar prognosis. In addition, patients with SI-DTC of 1-4 cm showed similar rates of CSM and ACM to T3 patients without ETE, LNM, and distant metastasis (DM). Similar results were obtained when we set the age cut-off value as 55 years, according to the 8th edition of AJCC TNM system.

CONCLUSIONS

Our study demonstrated that sex, age, and tumor size clearly differentiate SI-DTC of 1-4 cm into low-and high-risk categories. Survival rates were significantly lower in subgroups containing old males with larger tumors compared to younger females with small tumors. Total thyroidectomy may be favored in these high-risk subgroup patients.

Does the ATA Risk Stratification Apply to Patients with Papillary Thyroid Microcarcinoma?

BACKGROUND

The incidence of papillary thyroid microcarcinoma (PTMC) has increased over the past decade. The American Thyroid Association (ATA) suggests that these patients may undergo either thyroid lobectomy or active surveillance. It remains unclear whether there exists a subgroup of PTMC patients who may benefit from more aggressive treatment due to increased risk of recurrence.

METHODS

We retrospectively reviewed 357 patients with PTMC who underwent surgery at a single institution from 2004 to 2016. Patients were classified according to 2015 ATA risk stratification for structural disease recurrence. Demographic, oncologic, and clinicopathologic data were compared between groups.

RESULTS

Out of 357 patients, 246 were classified as low-risk PTMC, 93 were intermediate-risk, and 18 were high-risk. There were more male patients in the high-risk group (38.9%) than the intermediate- (31.2%) or low-risk groups (15.4%) (p < 0.001). Patients with low-risk microcarcinomas were more likely to have an incidental PTMC when compared to intermediate- or high-risk groups (98[39.8%], 15[16.1%], 1[5.6%], respectively, p < 0.001). Patients with high-risk PTMCs, compared to those with intermediate- and low-risk PTMCs, were more likely to have rising postoperative thyroglobulin levels after total thyroidectomy (6[40.0%], 4[5.1%], 9[5.7%], respectively, p = 0.001) and structural recurrence after lobectomy or total thyroidectomy (3[16.7%], 0[0%], 0[0%], respectively, p < 0.001). The median follow-up time was 17.5 (IQR 3-55) months.

CONCLUSIONS

Patients with high-risk PTMC have an increased risk of recurrence when compared to low- and intermediate-risk microcarcinomas, whereas intermediate-risk PTMC may behave similarly to low-risk tumors. ATA risk stratification may inform clinical decision making for patients with PTMC.

Appraisal of radioiodine refractory thyroid cancer: advances and challenges

The incidence of thyroid cancer ranks top among all endocrine cancers, which has increased worldwide. Some patients suffer from recurrent/residual diseases after primary treatment. The recurrent/residual disease often turns out to be radioiodine refractory and shows poor response to radioiodine therapy. A lot of studies have explored the precise appraisal of radioiodine refractory disease in recent years. The mechanism of iodine uptake and the definition of radioiodine refractory disease have been summarized and discussed. The advances in tumor characteristics, histologies, and mutant conditions have been explored for a more accurate method in the early-stage appraisal. We then offer a review of opinions in the evaluation of refractory disease during follow-up, including Tg doubling time, ¹⁸F PET/CT, ¹³¹I WBS, and others. The sensitivity and specificity have been compared between different diagnostic methods. Some novel methods may be introduced for more precise appraisal, such as a scoring system and RNA expression profiling. This review aims to provide physicians a broad insight into the appraisal of radioiodine refractory disease and to pave way for future study.