Incidental Papillary Thyroid Microcarcinoma Research Articles

Incidental papillary thyroid microcarcinoma: implications of recurrence and survival on management recommendations

Incidental papillary thyroid microcarcinoma: implications of recurrence and survival on management recommendations

Fate of nondiagnostic thyroid fine needle aspirations.

Thyroid nodules may be detected during the workup of thyroid hormone abnormalities and as incidental findings during unrelated imaging studies. The diagnosis of a thyroid nodule is mainly established by performing fine needle aspiration (FNA) under ultrasound guidance. Thyroid nodules are classified as nondiagnostic, defined in the Bethesda System for Reporting Thyroid Cytopathology as samples with excess blood, cyst fluid only, and lack of thyroid follicular cells. The current study evaluates a series of nondiagnostic FNAs to assess whether repeat sampling improves yield and what patient management, and outcomes are after a nondiagnostic FNA. Thyroid FNAs from 2016 to 2023 were retrieved from our institution archives. All cases were performed under ultrasound guidance and with rapid on-site evaluation. Cases were assigned the Bethesda System Category. Nondiagnostic FNAs were further reviewed for repeat FNA procedures, potential molecular testing, or diagnostic resections. In total 3104 thyroid FNAs were reviewed, with 153 (4.9%) being nondiagnostic. Of the 154 FNAs, there were 129 patients with an average age of 60 and a male-to-female ratio of 1:3.2. Of the 130 patients, there were 50 patients who underwent 55 repeat FNAs. Thirty-seven (67%) of the repeats were benign, 13 (24%) were nondiagnostic again, and 5 (9%) were atypia of undetermined significance (AUS). Molecular testing was performed on repeat FNAs diagnosed AUS. Four cases showed no mutations and had a high likelihood of being benign. One case did have an NRAS Q61R mutation, and resection revealed a noninvasive follicular thyroid neoplasm with papillary-like nuclear features. Seventeen (13% of all cases) with nondiagnostic FNA were resected. Twelve (71%) thyroidectomies showed benign adenomatous nodules. The remainder showed incidental papillary thyroid microcarcinoma (0.1 cm), an infarcted follicular adenoma, a noninvasive follicular thyroid neoplasm with papillary-like nuclear features, and metastatic renal cell carcinoma (2×). Thyroid nodules with nondiagnostic cytology are reassuring of being highly likely a benign nodule. Only 5 of the 55 (9%) repeat FNAs yielded abnormalities, with only one of those being truly a follicular neoplasm (confirmed by molecular testing and resection). No primary thyroid malignancies have been identified in follow-up (repeat FNA or surgery). Clinical and ultrasound follow-up may be more appropriate management for nondiagnostic thyroid FNAs.

Thyrotropin (TSH) and thyroid autoimmunity are predictive factors for the incidental discovery of papillary thyroid microcarcinoma during thyroidectomy.

To identify clinical, biological and pathological risk factors for the incidental discovery of papillary thyroid microcarcinomas (PTMCs) in patients undergoing thyroidectomy for presumed benign conditions. Cross sectional, single center study, involving all consecutive patients (N = 3015) who were submitted to thyroid surgery between 2001-2019. All medical files were retrospectively reviewed. A total of 1961 patients in the benign group and 145 patients in PTMC group were analyzed. No significant differences in age, sex, body mass index, smoking status, thyroid volume or weight and preoperative thyroxine treatment between benign and PTMC groups were observed. Circulating anti- thyroid antibodies, histological thyroiditis and serum thyrotropin (TSH) were significantly associated with PTMC in univariable analysis. Independent risk factors for incidental PTMC by multivariable analysis where possible (OR: 1.51, 95% CI: 0.99-2.28) and certain (OR: 1.74, 95% CI: 1.09-2.78) thyroid autoimmunity (p = 0.002) and higher serum TSH (OR: 1.25, 95% CI: 1.08-1.45, p = 0.03), whereas thyroid lobectomy was associated with a lower risk of PTMC (OR: 0.40, 95% CI: 0.24-0.67, p < 0.001). The most frequent genetic alteration was BRAFV600E mutation, found in 56.3% of PTMC submitted to DNA sequencing. No association between clinical, biological or histological characteristics of PTMC and BRAFV600E mutation was observed. Thyroid autoimmunity and higher preoperative serum TSH level were independent predictors of PTMC incidentally discovered during thyroid surgery. Larger prospective studies are needed to better identify possible risk factors for papillary thyroid carcinoma initiation and progression.

Papillary Thyroid Microcarcinoma: Differences between Lesions in Incidental and Nonincidental Settings-Considerations on These Clinical Entities and Personal Experience.

Papillary thyroid microcarcinoma (PTMC) represents 35-40% of all papillary cancers; it is defined as a nodule ≤ 10 mm at the time of histological diagnosis. The clinical significance of PTMC is still controversial, and it may be discovered in two settings: incidental PTMC (iPTMC), in which it is identified postoperatively upon histological examination of thyroid specimens following thyroid surgery for benign disease, and nonincidental PTMC (niPTMC), in which it is diagnosed before surgery. While iPTMC appears to be related to mild behavior and favorable clinical outcomes, niPTMC may exhibit markers of aggressiveness. We retrospectively review our experience, selecting 54 PTMCs: 28 classified as niPTMC (52%) and 26 classified as iPTMC (48%). Patients with niPTMC showed significant differences, such as younger age at diagnosis (p < 0.001); a lower male/female ratio (p < 0.01); a larger mean nodule diameter (p < 0.001); and a higher rate of aggressive pathological findings, such as multifocality, capsular invasion and/or lymphovascular invasion (p = 0.035). Other differences found in the niPTMC subgroup included a higher preoperative serum TSH level, higher hospital morbidity and a greater need for postoperative iodine ablation therapy (p < 0.05), while disease-free long-term survival did not differ between subgroups (p = 0.331) after a mean follow-up (FU) of 87 months, with one nodal recurrence among niPTMCs. The differences between iPTMC and niPTMC were consistent: patients operated on for total thyroidectomy and showing iPTMC can be considered healed after surgery, and follow-up should be designed to properly calibrate hormonal supplementation; conversely, niPTMC may sometimes exhibit aggressive behavior, and so the FU regimen should be closer and aimed at early detection of cancer recurrence.

Abstract #1403009: Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: First Reported Cases in the US

The incidence of papillary thyroid microcarcinoma (PTMC) is rising with increased utility and advancement of radiology imaging. Conservative treatment is highly considered given indolent nature of the disease. There has been a growing trend around the world to treat low risk PTMC with thermal ablation, such as radiofrequency ablation (RFA), a minimally invasive procedure that preserves most of thyroid parenchyma and function. This study is the first to report the efficacy and safety of RFA for low-risk PTMC in a large referral center in the US. The study included 10 patients who underwent RFA to treat low risk PTMC between July 2020 and February 2022. Patients who had cytological confirmation of single PTMC without evidence of metastasis, and ineligibility or refusal to undergo surgery were included. RFA were performed by three interventional radiologists. RFA technique and type of anesthesia were described. Thyroid function, changes in ablated tumor sizes, as well as procedure-related complications were retrospectively analyzed up to 18 months follow-up. Nine females and 1 male were included; median age was 44 years (range 29 – 69). Nine patients had normal thyroid function before and after RFA, and one patient had transient hyperthyroidism at 3 months follow up. Seven patients underwent general anesthesia, 2 patients had deep sedation, and 1 patient had moderate sedation. Mean duration of RFA was 6.32 minutes (SD +/- 4.25) with energy delivered ranging between 25 – 45 Watts. Mean volume of PTMC at baseline was 0.3 mL SD+/- 0.22. There was an increase in ablated volume at 3 months measuring 1.02 mL SD +/- 0.76, followed by a reduction in ablated nodule volume at 6 months measuring 0.42 mL SD +/- 0.38, and at 12 months measuring 0.26 mL SD +/- 0.28. The ablated nodules almost disappeared by 18 months follow-up, measuring 0.05 mL +/- 0.03 with no evidence of recurrence. There were no procedure-related major complications in any of the patients. This is the first reported cases of low risk PTMC treated with RFA in the US. The ablated volume initially increased as expected due to ablation beyond the nodules margin, followed by a gradual decrease in volume. RFA is safe and effective for the treatment of low risk PTMC. This therapy is potentially expanding in the US. Further study with longer follow up is needed to evaluate the risk of recurrence.

THADA-IGF2BP3 fusions detected in fine-needle aspiration specimens of thyroid nodules: An institutional experience.

Though the clinical significance of THADA-IGF2BP3 fusions detected in thyroid nodules preoperatively is still under investigation, the limited literature suggests these lesions are clinically low-risk. The pathology archives were searched from 2018 to 2022 for all thyroid nodules with a THADA-IGF2BP3 fusion detected via ThyroSeqV3® analysis. Patient demographics and tumor characteristics were collected. Statistical analyses were performed and p < .05 was considered statistically significant. This study was approved by the institutional review board. The case cohort included 34 thyroid nodules with THADA-IGF2BP3 fusions from 32 patients (average age-56.1 years, range: 30-86, male to female ratio-10:22). The average nodule size was 3.2cm (range: 1.3-7.3cm). At the time of biopsy, 21 cases were diagnosed as atypia of undetermined significance/follicular lesion of undetermined significance, 12 as follicular neoplasm/suspicious for follicular neoplasm and 1 as suspicious for malignancy. Surgical resection was performed in 29 patients (13 partial and 16 total thyroidectomies) to give a total of 31 nodules. Papillary thyroid carcinoma was diagnosed in 19/31 (61%) cases. No cases showed extrathyroidal extension or lymphovascular invasion. The remaining cases were considered either a low-risk neoplasm or benign. Four cases of NIFTP on final surgical pathology harbored concurrent incidental papillary thyroid microcarcinoma. One patient had the THADA-IGF2BP3 fusion detected in bilateral nodules. THADA-IGF2BP3 fusions can occur in malignant, low-risk and benign thyroid neoplasms, where malignant neoplasms show lack of aggressive features. Therefore, such entities can be classified as clinically low risk.

Progress in active surveillance for adult low-risk papillary thyroid microcarcinoma

The incidence of papillary thyroid microcarcinoma （PTMC） increases rapidly. However, epidemiological and autopsy studies show that the prevalence of low-risk papillary thyroid microcarcinoma （LR-PTMC） is very high, but the mortality is very low. There is over-diagnosis and over-treatment for LR-PTMC. Active surveillance （AS） was adopted for LR-PTMCs instead of immediate surgery, and more than 70% of the lesions remained stable or shrank in clinical observation. Therefore, AS is recommended for LR-PTMCs in clinical guidelines of several academic organizations around the world. However, PTMC is not equal to low-risk cancer. The implementation of AS strategy requires a strict grasp of indications and full consideration of population characteristics to ensure the maximum benefit of patients. This paper summarizes the present clinical progress of active surveillance for adult LR-PTMC.

Radioactive Iodine Ablation Can Reduce the Structural Recurrence Rate of Intermediate-Risk Papillary Thyroid Microcarcinoma: A Meta-Analysis.

Background The incidence of papillary thyroid microcarcinoma (PTMC) has significantly increased in recent years, and the decision to use radioactive iodine (RAI) ablation in low-risk (LR) and intermediate-risk (IR) patients is controversial. The aim of this study was to evaluate whether RAI ablation can reduce the recurrence rate in LR-IR PTMC patients. Methods A comprehensive literature search of the PubMed, Embase, Cochrane Library, and Web of Science was conducted according to the PRISMA statement. Results There were 8 studies in English that fit our search strategy, and a total of 2847 patients were evaluated. The results of the meta-analysis showed RAI ablation in LR-IR PTMC patients did not reduce cancer recurrence (risk radio (RR) 0.56, 95% CI 0.19-1.70, P = 0.31). Nevertheless, we further performed data analysis and found that IR PTMC patients without RAI ablation had a higher rate of cancer recurrence than those who underwent RAI ablation (RR 0.23, 95% CI 0.11-0.49, P = 0.0001). Furthermore, patients with risk factors for lymph node metastasis (RR 0.16, 95% CI 0.06-0.42, P = 0.0002), microscopic extrathyroidal extension (RR 0.19, 95% CI 0.06-0.60, P = 0.005), and multifocality (RR 0.13, 95% CI 0.04-0.45, P = 0.001) in the absence of RAI ablation were more likely to have recurrence. Conclusions Based on our current evidence, RAI ablation can reduce the cancer recurrence rate over 5 years in IR PTMC patients, especially when patients have some risk factors, such as lymph node metastasis, microscopic extrathyroidal extension, and multifocality.

Incidentally discovered papillary thyroid microcarcinoma in patients undergoing thyroid surgery for benign disease.

The incidence of thyroid carcinoma has grown significantly over the last few decades. A possible explanation is the increased diagnosis of small thyroid microcarcinoma (TMc). TMc reach a maximum diameter of ≤1 cm, identified during histopathology examination following a thyroidectomy performed for reasons not pertaining to malignancy. This study aims to investigate the prevalence of papillary thyroid microcarcinoma (PTMc) according to the benign pathology that refers patients to surgery and its trend evolution. Retrospective cohort analysis of 1815 patients who underwent total thyroidectomy for non-malignant diseases in the 2005-2020 period. The mean age of the subjects was 53.5 years, with a higher proportion of women (1481, 82.1%). A total of 167 PTMc (9.3%) were incidentally discovered. A multivariate logistic regression analysis was performed, showing no differences in prevalence according to sex or age in patients with PTMc compared to final benign histology. Multinodular goiter increases the risk of PTMc with an odds ratio of 2.2 (p = 0.001) compared to Hashimoto's thyroiditis and Graves' disease (GD). There is a statistically significant increase in the incidence of PTMc in the group operated in the 2017-2020 vs. 2005-2008 period (p = 0.005). The overall prevalence of PTMc in patients who underwent thyroid surgery for the benign disease was 9.3%. Thyroid nodular hyperplasia was the most frequent benign pathology associated with PTMc compared to Hashimoto's or GD. Gender and age were not correlated with the prevalence of TMc. Over the years, surgical findings of PTMc have grown, particularly in the 2017-2020 period.

Clinicopathological Findings Associated With Cervical Lymph Node Metastasis in Papillary Thyroid Microcarcinoma: A Retrospective Study in China.

ObjectiveThe incidence of papillary thyroid microcarcinoma (PTMC) has increased sharply during the past decades. Yet, whether or not nodal dissection should be performed remains controversial. This article aims to assess the high-risk factors associated with cervical lymph node metastasis (LNM) in patients with PTMC, which may potentially guide clinical management decision-making.MethodsMedical records of 449 PTMC patients who underwent thyroidectomy in our hospital from August 2016 to July 2017 were retrospectively reviewed. Clinical and pathological factors of the patients were anonymously extracted from the charts and analyzed.ResultThe patients were classified into two subgroups according to maximum tumor size measured through post-surgical pathology: smaller PTMC group (≤5 mm) and larger PTMC group (>5 mm). Larger tumor size was found to be associated with a higher rate of LNM (P = .001), particularly central lymph node metastasis (CLNM) (P = .001). Tumor size was also associated with extrathyroidal tumor extension (ETE) (P < .001), bilateral lesions (P = .015), and BRAFv600e mutation (P = .004). LNM was found to be more common in older patients (>55 y) (P = .030), and those with multifocal cancer (P < .001). In PTMC patients with unilateral lesions without ETE, tumor size was not significantly associated with LNM (P = .121).ConclusionsFor the PTMC population, tumor size was an independent risk factor for LNM, particularly for patients of old age (>55 y), and multifocality. However, in PTMC patients with unilateral lesions without extrathyroidal extension, tumor size was not related to the risk of LNM. These findings may potentially guide clinical decision-making in terms of cervical nodal dissection.

One year follow-up of US-Guided radiofrequency ablation for low-risk papillary thyroid microcarcinoma: The first experience in Taiwan

The incidence of papillary thyroid microcarcinoma (PTMC) has increased rapidly in recent decades, with a favorable overall prognosis. We aimed to evaluate the efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) for treating low-risk PTMC in Taiwan. This prospective study included patients with PTMC who were ineligible or refused surgery and underwent US-guided RFA between October 2018 and June 2020. US and computed tomography (CT) were performed before RFA to assess tumor lesions and exclude cervical lymph node metastasis. Sequential US follow-up following RFA was performed after 1, 3, 6, and 12 months, and yearly thereafter. Volume reduction ratio (VRR) and complete disappearance rate of tumor at one year were evaluated. 13 PTMCs in 12 patients were enrolled with a mean follow-up of 16.2±8.1 months (range, 1-24 months). The median largest tumor diameter and tumor volume before RFA were 0.76cm and 0.15ml (range, 0.02-0.37ml). The median (interquartile range, IQR) volume and VRR at 12 months post-RFA were 0 (0, 0.03) ml (p=0.033) and 100% (84.26%, 100%) (p=0.008). Eight tumors (61.54%) were completely disappeared at 12 months post-RFA and no tumor recurrence, lymph nodes, or distant metastasis were noted. All tumors were successfully treated without complications. Minimally invasive US-guided RFA is an effective and safe alternative for low-risk PTMC, resulting a satisfied VRR.

Papillary thyroid microcarcinoma: distinct form or cancer growth stage?

Background. Over the past decades an increase in the incidence of papillary thyroid microcarcinoma (PTMC) has been observed throughout the world owing to the improved diagnostics. There are many different opinions about the aggressiveness degree of this group of tumors, as well as about the tactics of managing patients with PTMC.Aim of the study is the identification of the prognostic factors responsible for the features of the clinical course, including the more aggressive one.Materials and methods. A study was carried out with a detailed analysis of a group of patients with papillary thyroid cancer ≤1 cm in size and the existing clinical data of regional and distant metastases. All patients underwent thyroidectomy with bilateral central cervical lymph node dissection. Factors such as gender, patient age, bilaterality, extrathyroid extension, the presence or absence of a capsule around the tumor node, the absence or presence of metastases in the central part were assessed. In 26.6% histological examination revealed metastatic lesions of the central group lymph nodes. Latent metastases were detected in 24.2% of women and 43% of men, in 36.7% of patients &lt;55 and in 14.3% of patients ≥ 55 years, in 29.5% with the absence of the node capsule and in 19.3% with encapsulated tumors, in 48.1% with multicentric growth and in 19.5% with a solitary neoplasm, in 21.7% with a tumor size ≤0.5 cm and in 27.9% with a node of 0.6–1 cm, in 24% with the absence of invasion of the thyroid capsule and in 31% with the presence of extrathyroid invasion, in 21% of patients with typical, in 26% with follicular and 43% with mixed papillary cancer. 95 patients received radioiodine therapy. No additional metastases were found in them.Results. When conducting univariate analysis, the main signs influencing the development of metastases in the central zone were age up to 55 years (p = 0.009, χ2 = 6.919) and multicentric neoplasm (p = 0.004, χ2 = 8.530); in multivariate analysis, similarly, age younger 55 years (p = 0.000, Exp B = 0.011, CI 95.0% 0.001–0.106) and multifocality (p = 0.027, Exp B = 2.686, CI 95.0% 1.119–6.448).Conclusion. PTMC is not a separate group or tumor morphotype, and the determination of treatment tactics for this group of patients should be based not only on the size of the tumor, but on the clinical and biological parameters of the tumor.

Папиллярная микрокарцинома щитовидной железы: отдельная нозология или одна из стадий развития рака?

Background. Over the past decades an increase in the incidence of papillary thyroid microcarcinoma (PTMC) has been observed throughout the world owing to the improved diagnostics. There are many different opinions about the aggressiveness degree of this group of tumors, as well as about the tactics of managing patients with PTMC. Aim of the study is the identification of the prognostic factors responsible for the features of the clinical course, including the more aggressive one. Materials and methods. A study was carried out with a detailed analysis of a group of patients with papillary thyroid cancer ≤1 cm in size and the existing clinical data of regional and distant metastases. All patients underwent thyroidectomy with bilateral central cervical lymph node dissection. Factors such as gender, patient age, bilaterality, extrathyroid extension, the presence or absence of a capsule around the tumor node, the absence or presence of metastases in the central part were assessed. In 26.6% histological examination revealed metastatic lesions of the central group lymph nodes. Latent metastases were detected in 24.2% of women and 43% of men, in 36.7% of patients <55 and in 14.3% of patients ≥ 55 years, in 29.5% with the absence of the node capsule and in 19.3% with encapsulated tumors, in 48.1% with multicentric growth and in 19.5% with a solitary neoplasm, in 21.7% with a tumor size ≤0.5 cm and in 27.9% with a node of 0.6–1 cm, in 24% with the absence of invasion of the thyroid capsule and in 31% with the presence of extrathyroid invasion, in 21% of patients with typical, in 26% with follicular and 43% with mixed papillary cancer. 95 patients received radioiodine therapy. No additional metastases were found in them. Results. When conducting univariate analysis, the main signs influencing the development of metastases in the central zone were age up to 55 years (p = 0.009, χ2 = 6.919) and multicentric neoplasm (p = 0.004, χ2 = 8.530); in multivariate analysis, similarly, age younger 55 years (p = 0.000, Exp B = 0.011, CI 95.0% 0.001–0.106) and multifocality (p = 0.027, Exp B = 2.686, CI 95.0% 1.119–6.448). Conclusion. PTMC is not a separate group or tumor morphotype, and the determination of treatment tactics for this group of patients should be based not only on the size of the tumor, but on the clinical and biological parameters of the tumor.

The Overdiagnosis of Thyroid Micropapillary Carcinoma: The Rising Incidence, Inert Biological Behavior, and Countermeasures

The incidence of papillary thyroid microcarcinoma (PTMC) has exponentially increased in the past three decades. The 2014 World Cancer Report stated that, among the new cases of thyroid carcinoma, >50% are PTMC. The incidence of thyroid cancer was growing by 20.1% annually in China. Most of PTMC have low risk and excellent prognoses. It must be realized that the problem of overdiagnosis of thyroid cancer is quite serious. In this article, we summarized the phenomenon and the cause of “overdiagnosis” of PTMC, the progress of clinical management, and the countermeasures.

Incidental micropapillary carcinoma in thyroidectomy specimens and criteria employed for Diagnosis - A Retrospective Study

Incidental Papillary thyroid Microcarcinoma (I-PTM) is a tumor focus that is clinically unsuspected before thyroid surgery and is identified in the final pathological examination of a thyroidectomy specimen. Papillary thyroid Microcarcinoma has a benign behavior with excellent prognosis in most cases and therefore several controversies regarding the need for completion surgery for excision of remaining thyroid tissue and lymphnodes exist. A total of 22 patients with PTM incidentally diagnosed on postoperative histopathological examination of the excised thyroid tissue were analyzed for assessing the rate of incidental diagnosis of PTM and their demographic features and the surgical procedures used for their treatment. I-PTM was diagnosed in 13.6 % of males and 86% of females respectively. The average age in cases with I-PTM was 40 years (range 25 to 65 years). Of the 22 cases of I-PTM, 11 were operated with a pre-diagnosis of Multi nodular goitre and 8 were operated with a pre-diagnosis of solitary nodule (colloid nodule /follicular adenoma).Total thyroidectomy was performed in 11 cases,sub-total thyroidectomy was performed in 9 cases and right hemithyroidectomy was performed in 2 cases. In one case of I-PTM lower margin of excision was involved and was subjected for radioiodine therapy at referral centre.

Clinico-pathological Characteristics of Incidental Papillary Thyroid Microcarcinoma

More than ten microscopic variants of PTC have been documented. The most common variant is classical type PTC, which may also be referred to as typical PTC or usual type PTC. The majority of PTCs are of the classical type. Diagnosis is based on typical nuclear features, which should be present in tumour cells. Papillary structures are not present in all tumours. Psammona bodies are sometimes present. Surgically treated patients between January 2017 and December 2020 were retrospectively analysed. The study involved 329 surgical patients with benign disease of the thyroid, without any diagnosis of preoperative malignancy. Generally cells with nuclear clearing were arranged around the fibrovascular core in histopathological eaxamination. No lymphovascular invasion was detected in any of the cases. Other histopathological findings accompanying I-PTM were MNG in 7 cases (64%), lymphocytic thyroiditis in 4 cases (36%) and Hashimoto’s thyroiditis in 1 case (9%).The mean size of the papillary thyroid foci was 5.7 mms.

Predictive Factors of Recurrence of Papillary Thyroid Microcarcinomas: Analysis of 2,538 Patients.

Introduction The incidence of papillary thyroid microcarcinoma (PTMC) has increased, and its treatment remains controversial. Objective To identify the clinical and pathological factors predictive of tumor recurrence. Methods We retrospectively analyzed 2,538 consecutive patients treated for PTMC, most submitted to total thyroidectomy (98%) followed by radioactive iodine (RAI) ablation (51.7%) at a cancer center from 1996 to 2015. The patients were stratified according to the American Thyroid Association (ATA) risk categories (low, intermediate, or high), and the clinicopathological features were evaluated by multivariate Cox regression analysis to identify independent prognostic factors for recurrence. Results After a mean follow-up of 58 months (range: 3 to 236.5 months), tumor recurrence was diagnosed in 63 (2.5%) patients, mostly in the lymph nodes. Distant metastasis occurred in 2 (0.1%) patients. There were no cancer-related deaths. The multivariate analysis showed that age < 55 years ( p = 0.049; hazard ratio [HR]: 2.54; 95% confidence interval [95%CI]: 0.95 to 0.99), multifocality ( p = 0.032; HR: 1.76; 95%CI: 1.05 to 2.96), and the presence of lymph-node metastasis ( p < 0.001; HR: 3.69; 95%CI: 2.07–6.57) were independent risk factors for recurrence. Recurrence was observed in 29 (1.5%) out of 1,940 low-risk patients, 32 (5.4%) out of 590 intermediate-risk patients, and in 2 (25%) out of 8 high-risk patients. Conclusions The prognosis of PTMC is excellent, favoring a conservative treatment for most patients. Age < 55 years, multifocality, and node metastasis at diagnosis, as well the ATA staging system effectively predict the risk of recurrence. The presence of these risk factors can help identify patients who should be considered for more aggressive management and more frequent follow-up.

Papillary thyroid microcarcinoma with minimal extrathyroidal extension. Is its course so indolent that it requires a less aggressive treatment?

BackgroundAlthough the incidence of papillary thyroid microcarcinoma (PTMC) has increased in recent decades, the role played by minimal extrathyroidal extension (mETE) in the prognosis of PTMC is still unclear. The aim of this study is to analyze the factors associated with PTMC with mETE and its long-term prognosis. Material and methodsWe conducted a retrospective study on patients with a histological diagnosis of PTMC. We excluded patients who had previously undergone thyroid surgery, those who had other synchronous malignancies, those with an ectopic location of the PTMC, and those lost to follow-up within two years. We compared group 1 (PTMC without extrathyroidal extension) to group 2 (PTMC with mETE) and performed a multivariate analysis. ResultsWe observed PTMC with mETE in 11.2% (n = 18) of patients. On the multivariate analysis, mETE was associated with an age ≥45 years (OR: 4.383; 95% CI: 1.051−18.283, p = .043), tumor size ≥8 mm (OR: 5.913; 95% CI: 1.795−19.481; p = .003), bilaterality (OR: 4.430; 95% CI: 1.294−15.173; p = .018) and metastatic lymph nodes (OR: 12.588; 95% CI: 2.919−54.280; p = .001). Over the mean follow-up period of 119.8 ± 65 months, one case of recurrence was detected in group 2 (0% vs. 5.6%; p = .112). No patients died of the disease. Disease-free survival was lower in group 2 (124.9 ± 5.6 vs. 97.4 ± 10.3 months; p = .034). ConclusionsThe mETE of PTMC is a factor of worse prognosis associated with the presence of metastatic lymph nodes and a lower rate of disease-free survival.

A Comparison of the Seventh and Eighth Editions of the AJCC Staging Systems to Predict Recurrence in Papillary Thyroid Microcarcinoma.

The incidence of papillary thyroid microcarcinoma has been constantly rising in recent decades. The tumor, node, metastasis staging system is designed to predict prognosis in patients with papillary thyroid carcinoma. Recent studies have shown that the American Joint Committee on Cancer (AJCC) 8th edition is superior to the 7th edition for predicting tumor recurrence in PTC patients. To date, whether the 8th edition is also better able to predict recurrence in papillary thyroid microcarcinoma (PTMC) remains unclear. We enrolled 1007 cases from our thyroid cancer database in the First Affiliated Hospital, Zhejiang University School of Medicine, from 1997 to 2011. Univariable and multivariate Cox hazard regression analyses were used to identify the association between variables and recurrence. Disease-free survival was calculated using the Kaplan-Meier method and compared using the log-rank test. A total of 1007 PTMC patients were enrolled, with a median follow-up of 67 months. Of 93 (9.2%) patients downstaged by the changes in versions, 49 (52.7%) were downstaged because the age-at-diagnosis cut-off used for staging increased from 45 to 55years, while 35 (37.6%) were downstaged due to the weakening of the effects of lymph node metastasis. The recurrence rate of PTMC was 4.17%. Univariate Cox hazards regression analyses showed that TNM stage according to the AJCC 8th edition was significantly associated with recurrence, while the recurrence survival curves showed that TNM stage (stage I vs. stage II-IV) according to the AJCC 8th edition, but not the 7th edition, was significantly associated with disease-free survival (p<0.05). The AJCC 8th edition has better ability to predict recurrence in PTMC patients than the 7th edition.

Characteristics and Prognostic Factors of Recurrence after Hemithyroidectomy in Patients with Papillary Thyroid Microcarcinoma

Background and Objectives The incidence of papillary thyroid microcarcinoma (PTMC) continues to increase worldwide. However, there is a lack of a comprehensive understanding of recurrence after hemithyroidectomy in patients with PTMC. We aimed to evaluate the characteristics and risk factors of recurrence after hemithyroidectomy in patients with PTMC.Subjects and Method We included 527 patients with PTMC who underwent hemithyroidectomy between 2009 and 2017.Results At a mean follow-up of 76.4 months after hemithyroidectomy, recurrence occurred in 4.2% (22/527) of the patients. The times of recurrence were &lt;12, 12-24, 24-36, 36-48, 48-60, and &gt;60 months after initial surgery in 1 (4.5%), 6 (27.3%), 5 (22.7%), 4 (18.2%), 4 (18.2%), and 2 (9.1%) patient(s), respectively. The most common recurrence site was the contralateral remaining thyroid lobe. In univariate analyses, only multifocality was demonstrated to be associated with an increased risk of recurrence [hazard ratio (HR), 2.834; confidence interval (CI), 1.044-7.693; &lt;i&gt;p&lt;/i&gt;=0.041). In multivariate analyses, multifocality (HR, 2.982; CI, 1.091-8.155; &lt;i&gt;p&lt;/i&gt;=0.033) and central lymph node metastasis (HR, 9.649; CI, 1.238-75.217; &lt;i&gt;p&lt;/i&gt;=0.030) were demonstrated to be associated with an increased risk of recurrence.Conclusion The follow-up after hemithyroidectomy for PTMC should focus on the postoperative 1–5-year period with meticulous inspection of the remaining thyroid lobe, particularly in patients with multifocality or central lymph node metastasis.