Classification of papillary thyroid microcarcinoma according to size and fine-needle aspiration cytology: Behavior and therapeutic implications

Ultrasonographical, clinical and histopathological features of 1264 nodules with papillary thyroid carcinoma and microcarcinoma based on tumor size

Objective

We aimed to evaluate the patients diagnosed with papillary thyroid carcinoma (PTC) and papillary thyroid microcarcinoma (PTMC) in terms of clinical, ultrasonographical (US) and histopathological features and their relationships with tumor size.

Methods

We retrospectively evaluated 881 patients who underwent thyroid surgery in our clinic and diagnosed with PTC histopathologically were enrolled the study. Demographic characteristics, US findings and histopathological features were evaluated.

Results

In total, 1264 nodules were identified in the 881 patients. The incidentality rates were higher in the PTMC group and also in the ≤ 5 mm group. In total multifocality rate was 32.9%, and was significantly higher in PTMC group than the PTC group. PTC and > 5 mm PTMC groups compared to PTMC and ≤ 5 mm groups respectively, were more aggresive histopathological features.

Conclusion

Since the incidentality rates were found significantly more common in our patients with PTMC and those with ≤ 5 mm, ultrasonographic features of the nodules should be evaluated carefully and for cases which are suspicious with US, US-guided fine needle aspiration biopsy (FNAB) should be considered in order to make the correct treatment strategy. Also our study revealed that PTC and > 5 mm PTMC groups compared to PTMC and ≤ 5 mm groups respectively, have more aggresive histopathological features.

Papillary thyroid microcarcinoma: characteristics at presentation, and evaluation of clinical and histological features associated with a worse prognosis in a Latin American cohort

Objective We aimed to describe the presentation of papillary microcarcinoma (PTMC) and identify the clinical and histological features associated with persistence/recurrence in a Latin American cohort. Subjects and methods Retrospective study of PTMC patients who underwent total thyroidectomy, with or without radioactive iodine (RAI), and who were followed for at least 2 years. Risk of recurrence was estimated with ATA 2009 and 2015 classifications, and risk of mortality with 7th and 8th AJCC/TNM systems. Clinical data obtained during follow-up were used to detect structural and biochemical persistence/recurrence. Results We included 209 patients, predominantly female (90%), 44.5 ± 12.6 years old, 183 (88%) received RAI (90.4 ± 44.2 mCi), followed-up for a median of 4.4 years (range 2.0-7.8). The 7th and 8th AJCC/TNM system classified 89% and 95.2% of the patients as stage I, respectively. ATA 2009 and ATA 2015 classified 70.8% and 78.5% of the patients as low risk, respectively. Fifteen (7%) patients had persistence/recurrence during follow-up. In multivariate analysis, only lymph node metastasis was associated with persistence/recurrence (coefficient beta 4.0, p = 0.016; 95% CI 1.3-12.9). There were no PTMC related deaths. Conclusions Our series found no mortality and low rate of persistence/recurrence associated with PTMC. Lymph node metastasis was the only feature associated with recurrence in multivariate analysis. The updated ATA 2015 and 8th AJCC/TNM systems classified more PTMCs than previous classifications as low risk of recurrence and mortality, respectively.

The first postoperative-stimulated serum thyroglobulin is a prognostic factor for thyroid microcarcinomas

INTRODUCTION

Endogenous thyroid-stimulating hormone-stimulated thyroglobulin collected after total thyroidectomy is a useful predictor of better prognosis in patients with differentiated thyroid carcinomas in general, but studies with microcarcinomas are scarce.

OBJECTIVE

To assess whether the first postoperative stimulated thyroglobulin measurement is a prognostic factor in patients with microcarcinoma.

METHODS

The medical data of 150 differentiated thyroid carcinoma patients were studied retrospectively, and 54 (36%) cases with microcarcinoma were selected. The first postoperative stimulated thyroglobulin (1st stimulated thyroglobulin), measured after thyroidectomy, initial presentation data, and microcarcinomas treatment were assessed regarding outcome. Worse prognosis was defined as neoplasm persistence/recurrence.

RESULTS

Persistence/recurrence occurred in 27.8% of the cases. These patients were identified according to the following parameters: receiving more than one ¹³¹iodine dose (100% vs. 0%; p<0.0001); accumulated ¹³¹iodine dose (232.14±99.09 vs. 144±33.61mCi; p<0.0001); presented active disease in the last assessment (53.3% vs. 0%; p<0.0001); follow-up time (103.07±61.27 vs. 66.85±70.14 months; p=0.019); and 1st stimulated thyroglobulin (19.01±44.18 vs. 2.19±2.54ng/dL; p<0.0001). After multivariate logistic regression, only the 1stSTg [odds ratio=1.242; 95% confidence interval: 1.022-1.509; p=0.029] and follow-up time (odds ratio=1.027; 95% confidence interval: 1.007-1.048; p=0.007) were independent predictors of risk of persistence/recurrence. The cutoff point of 1.6ng/dL for the 1st stimulated thyroglobulin was significantly associated with disease persistence/recurrence [area under the curve=0.713 (p=0.019)].

CONCLUSION

The first stimulated thyroglobulin predicted disease persistence/recurrence in patients with microcarcinoma.

CIRCULATING THYROID-STIMULATING HORMONE RECEPTOR MESSENGER RNA AS A MARKER OF TUMOR AGGRESSIVENESS IN PATIENTS WITH PAPILLARY THYROID MICROCARCINOMA

BACKGROUND

We have previously shown that thyroid-stimulating hormone receptor messenger RNA (TSHR mRNA) is detectable in the peripheral blood of patients with papillary thyroid microcarcinoma (PTmC). The aim of this study was to analyze the utility of TSHR mRNA status as a marker of tumor aggressiveness in patients with PTmC.

METHODS

Preoperative TSHR mRNA values were obtained in 152 patients who underwent thyroidectomy and were found to have PTmC on final pathology. Clinical parameters were analyzed from an institutional review board-approved database using χ(2) and t tests.

RESULTS

Preoperatively, TSHR mRNA was detected in the peripheral blood in 46% of patients, which was less than that for macroscopic papillary thyroid carcinoma (PTC) (80%) but higher than for benign thyroid disease (18%) (P<.001). The focus of cancer was larger in the TSHR mRNA-positive group compared to the negative group (0.41 vs. 0.30 cm, respectively, P = .015). The prevalence of tall-cell variant was higher in the TSHR mRNA positive group. The rates of lymph node (LN) metastasis (16% vs. 10%), multifocality (46% vs. 49%), and extra-thyroidal extension (10% vs. 5%) were similar between the TSHR mRNA-positive and-negative groups, respectively. In patients 45 years or older, rate of LN metastasis was higher in those who were TSHR mRNA positive (10%) versus negative (2%) (P = .039). TSHR mRNA positivity predicted a higher likelihood of radioactive iodine treatment (36% vs. 17%, P = .009) postoperatively.

CONCLUSION

This study shows that TSHR mRNA, which is a marker of circulating thyroid cancer cells, is detectable in about half of patients with PTmC. The positivity of this marker predicts a higher likelihood of LN involvement in patients with PTmC who are 45 years or older.

Differences in the recurrence and mortality outcomes rates of incidental and nonincidental papillary thyroid microcarcinoma: a systematic review and meta-analysis of 21 329 person-years of follow-up

CONTEXT

There is controversy as to whether papillary thyroid microcarcinoma (PTMC) represents more than one disease entity with different outcomes, requiring different treatment.

OBJECTIVES

To compare characteristics, outcomes, and factors associated with prognosis of incidental and nonincidental PTMC.

SETTING AND DESIGN

Two reviewers performed searches of online databases (1966-2012), reference lists, and conference abstract books. Longitudinal studies of subjects >16 years old receiving any treatments for papillary thyroid cancer ≤10 mm in size were included. Two reviewers independently screened abstracts and articles, extracted data, and assessed quality of studies using National Institute of Clinical Excellence and PRISMA criteria.

RESULTS

Of 1102 abstracts identified, 262 studies were reviewed and 17 studies included, comprising 3523 subjects, with mean follow-up of 70 months and total follow-up of 21 329 person-years. This included 854 subjects with incidental PTMC (follow-up, 4800 person-years; mean tumor size, 4.6 mm [range 3.3-6.7 mm]) and 2669 nonincidental PTMC cases (follow-up, 16 529 person-years; mean tumor size, 6.9 mm [range 5.6-8.0 mm]). The recurrence rate in the incidental group (0.5%; 95% confidence interval [CI], 0-1%, P < .001) was significantly lower than that in the nonincidental group PTMC (7.9%; 95% CI, 5-11%), with an OR of recurrence of 14.7 (95% CI, 5.6-54.8, P < .001) for nonincidental PTMC, compared with incidental PTMC. Lymph nodes were involved in 80% (126/157) of recurrences. On meta-regression, age, sex, size, tumor multifocality, lymph node involvement, and treatment modality were not significantly associated with recurrence.

CONCLUSIONS

Our meta-analysis strongly suggests the existence of at least two distinct entities of PTMC. Incidental PTMC has different clinical characteristics and a much lower recurrence rate than nonincidental PTMC, suggesting that management protocols should be re-considered. Additional studies with standardized data collection are required to explore potential differences between subgroups of nonincidental PTMC.

Differences in the characteristics of papillary thyroid microcarcinoma ≤5 mm and >5 mm in diameter

BACKGROUND

The behavior and optimal management of papillary thyroid microcarcinomas (PTMCs) after thyroidectomy remain unclear. The purpose of this study was to compare the clinicopathologic features and tumor recurrence rates of patients with PTMCs ≤5 mm and >5 mm in diameter after total thyroidectomy.

METHODS

A group of patients with PTMCs ≤5 mm (n=83) has been compared to a group with >5 mm (n=122). All of these patients had conventional type PTMCs and were followed up for 5 years. Both the histology and the outcome have been compared.

RESULTS

Sex (p=.014) and extrathyroidal extension (p=.003) of patients in the ≤5 mm and >5 mm groups differed significantly. Two and 5 patients from these groups, respectively, experienced tumor recurrence within 5 years (2.4% vs 4.1%; p=.634).

CONCLUSION

The clinicopathologic features of PTMCs ≤5 mm and >5 mm are similar, except for sex distribution and extrathyroidal extension. The 5-year recurrence rate in the 2 groups did not differ significantly.

Distinguishing classical papillary thyroid microcancers from follicular-variant microcancers

BACKGROUND

Papillary thyroid microcarcinomas (mPTCs), tumors less than or equal to 1 cm, have been considered the same clinical entity as microfollicular-variant papillary thyroid microcarcinomas (mFVPTCs). The purpose of this study was to use population-level data to characterize differences between mFVPTC and mPTC.

MATERIALS AND METHODS

We identified adult patients diagnosed with mFVPTC or mPTC between 1998 and 2010 in the Surveillance, Epidemiology, and End Results database. Binary comparisons were made with the Student t-test and chi-squared test. Multivariate logistic regression was used to further analyze lymph node metastases and multifocality.

RESULTS

Of the 30,926 cases, 8697 (28.1%) were mFVPTC. Multifocal tumors occurred with greater frequency in the mFVPTC group compared with the mPTC group (35.4% versus 31.7%; P<0.01). Multivariate logistic regression indicated that patients with mFVPTC had a 26% increased risk of multifocality (odds ratio, 1.26; 95% confidence interval, 1.2-1.4; P<0.01). In contrast, lymph node metastases were nearly twice as common in the mPTC group compared with the mFVPTC group (6.8% versus 3.6%; P<0.01). Multivariate logistic regression confirmed that patients with mPTC had a 69% increased risk of lymph node metastases compared with patients with mFVPTC (odds ratio, 1.69; 95% confidence interval, 1.4-2.0; P<0.01).

CONCLUSIONS

Multifocality is not unique to classical mPTC and occurs more often in mFVPTC. The risk of lymph node metastases is greater for mPTC than mFVPTC. The surgeon should be aware of these features as they may influence the treatment for these microcarcinomas.

Prognostic factors in papillary microcarcinoma with emphasis on histologic subtyping: a clinicopathologic study of 148 cases

BACKGROUND

There continues to be controversy regarding which clinicopathological features confer a higher risk of adverse outcome in papillary microcarcinomas (PMC). The aim of this study was to assess the prognostic value of a meticulous histologic examination in PMC.

METHOD

All papillary thyroid carcinoma <1 cm in size without associated larger thyroid carcinomas, identified between 1977 and 2002, were categorized as PMC and subjected to a meticulous histopathologic examination by 2 thyroid pathologists.

RESULTS

148 PMC patients fulfilled the inclusion criteria. Within PMC, young age, male sex, tumor multicentricity, extrathyroidal extension, and infiltrative and larger tumor (≥0.5 cm) correlated with the presence of >1 cm metastatic node (MN) or >3 MN at presentation (p<0.05). With a median follow-up of 9.9 years, only 1 (0.7%) of 134 PMC patients died of thyroid carcinomas and 3 (2.2%) had recurrences in the neck. The patient who died had harbored a poorly differentiated carcinoma in his MN. The presence of MN and especially a large MN (>1 cm) correlated with worse recurrence-free survival (p=0.005 and p<0.0001, respectively). Except for one, all individuals with clinically adverse outcomes had >1 cm MN. Patients whose MNs were predominantly composed of poorly differentiated carcinoma or tall cell variant papillary thyroid carcinoma had a significant shorter recurrence-free survival (p<0.0001). Only 1 of 80 radioactive iodine-naïve PMC patients with absent or small MN (≤1 cm) had recurrence with a median follow-up of 9.2 years.

CONCLUSIONS

(i) The size and histotype of the MN are predictors of outcome in PMC and should be recorded. (ii) The very rare PMC patients who suffer recurrence or even die of disease have usually aggressive histopathologic features at presentation. (iii) PMC patients with nodal disease that is small or absent at presentation are at a very low risk of recurrence and may be spared radioactive iodine therapy.

BRAF: a tool in the decision to perform elective neck dissection?

BACKGROUND

Some studies have demonstrated a correlation between the presence of a BRAF mutation and aggressive characteristics, including lymph node metastasis in papillary thyroid carcinoma (PTC). Prophylactic central neck dissection (CND) has been proposed for treatment of PTC. Given the potential complications of CND, we undertook a prospective study to determine the correlation between the BRAF mutation and lymph node metastasis.

METHODS

A total of 51 patients with PTC underwent total thyroidectomy and routine prophylactic CND. All patients were tested for the BRAF mutation.

RESULTS

Positive lymph nodes were found in 54.9% of patients. The BRAF mutation was found in 15 patients (29%). BRAF was not correlated with lymph node metastases. Lymph node metastases were correlated with multifocality (p=0.005) and angiolymphatic invasion (p=0.003) in univariate analysis. Age was also significant in multivariate analysis.

CONCLUSIONS

Testing for the BRAF mutation does not help in deciding whether or not to perform CND.

The significance of neutrophil/lymphocyte ratio as a possible marker of underlying papillary microcarcinomas in thyroidal goiters: a pilot study

BACKGROUND

Preoperatively elevated neutrophil/lymphocyte ratio (NLR) is a negative prognostic factor of survival in various types of cancers. A retrospective study was conducted to examine if preoperative elevation of NLR is associated with higher risk for incidental papillary thyroid microcarcinoma (PTMC).

METHODS

The study sample consisted of 26 patients with benign goiters, 31 patients with incidental PTMC, 26 patients preoperatively diagnosed with thyroid cancer, and 26 healthy controls. NLRs were compared regarding thyroidal pathology.

RESULTS

The mean preoperative NLR was significantly elevated in patients with PTMC and thyroid cancer. In addition, the third and fourth quartiles of NLR included only patients with either PTMC or thyroid cancer. No significant differences in NLR occurred between patients with multifocal and unifocal PTMC.

CONCLUSIONS

NLRs were significantly elevated in patients with incidental PTMC and thyroid cancer. The findings of this pilot study indicate that NLR should be considered an easily accessible biomarker for detecting incidental PTCM; nevertheless, further studies are required to confirm these preliminary results.

Papillary thyroid microcarcinoma: clinicopathological characteristics and implications for treatment in 276 patients

BACKGROUND

There is debate concerning the clinical significance of papillary thyroid microcarcinoma (PTMC), and therefore, the rise in the incidence of PTMC creates management dilemmas. The purpose of this study was to analyse the clinicopathological characteristics of PTMC in an island region that has a high prevalence of goitre and to determine risk factors for the worst prognosis.

MATERIALS AND METHODS

Data from 1874 patients who underwent a total thyroidectomy between January 2002 and December 2008 were reviewed retrospectively. A total of 276 patients who were diagnosed with PTMC in a final pathology report were included in the study. A PTMC was defined as a papillary thyroid carcinoma with a diameter ≤ 10 mm. Clinicopathological features were evaluated by both univariate and multivariate analyses.

RESULTS

Of the 276 patients with PTMC, 219 patients (79·3%) were incidentally diagnosed. Two hundred and two patients had carcinomas of ≤ 5 mm, and 74 patients presented with carcinomas that ranged in size from 0·6 to 1·0 cm. Lymph node metastasis was diagnosed in 3·5% of patients with tumours ≤ 5 mm, and 21·6% of patients presented tumours > 5 mm. Upon multivariate analysis, clinically suspected diagnosis, a tumour size > 5 mm and an age over 45 years at diagnosis were independent risk factors for capsule invasion, while tumour multifocality, bilaterality, size of tumour > 5 mm and thyroid capsule invasion were independent risk factors for lymph node metastasis at diagnosis.

CONCLUSIONS

Patients presenting multifocal, bilateral PTMC with a maximum diameter > 5 mm and thyroid capsule invasion may have an increased risk of lymph node metastasis. These factors should be considered in the follow-up for these patients.