Managing thyroid microcarcinomas

Thyroid Carcinoma, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Differentiated thyroid carcinomas is associated with an excellent prognosis. The treatment of choice for differentiated thyroid carcinoma is surgery, followed by radioactive iodine ablation (iodine-131) in select patients and thyroxine therapy in most patients. Surgery is also the main treatment for medullary thyroid carcinoma, and kinase inhibitors may be appropriate for select patients with recurrent or persistent disease that is not resectable. Anaplastic thyroid carcinoma is almost uniformly lethal, and iodine-131 imaging and radioactive iodine cannot be used. When systemic therapy is indicated, targeted therapy options are preferred. This article describes NCCN recommendations regarding management of medullary thyroid carcinoma and anaplastic thyroid carcinoma, and surgical management of differentiated thyroid carcinoma (papillary, follicular, Hürthle cell carcinoma).

Analysis of Malignant Thyroid Nodules That Do Not Meet ACR TI-RADS Criteria for Fine-Needle Aspiration

OBJECTIVE. Compared with other guidelines, the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) has decreased the number of nodules for which fine-needle aspiration is recommended. The purpose of this study was to evaluate the characteristics of malignant nodules that would not be biopsied when the ACR TI-RADS recommendations are followed. MATERIALS AND METHODS. We retrospectively reviewed a total of 3422 thyroid nodules for which a definitive cytologic diagnosis, a definitive histologic diagnosis, or both diagnoses as well as diagnostic ultrasound (US) examinations were available. All nodules were categorized using the ACR TI-RADS, and they were divided into three groups according to the recommendation received: fine-needle aspiration (group 1), follow-up US examination (group 2), or no further evaluation (group 3). RESULTS. Of the 3422 nodules, 352 were malignant. Of these, 240 nodules were assigned to group 1, whereas 72 were assigned to group 2 and 40 were included in group 3. Sixteen of the 40 malignant nodules in group 3 were 1 cm or larger, and, on the basis of analysis of the sonographic features described in the ACR TI-RADS, these nodules were classified as having one of five ACR TI-RADS risk levels (TR1-TR5), with one nodule classified as a TR1 nodule, eight as TR2 nodules, and seven as TR3 nodules. If the current recommendation of no follow-up for TR2 nodules was changed to follow-up for nodules 2.5 cm or larger, seven additional malignant nodules and 316 additional benign nodules would receive a recommendation for follow-up. If the current size threshold (1.5 cm) used to recommend US follow-up for TR3 nodules was decreased to 1.0 cm, seven additional malignant nodules and 118 additional benign nodules would receive a recommendation for follow-up. CONCLUSION. With use of the ACR TI-RADS, most malignant nodules that would not be biopsied would undergo US follow-up, would be smaller than 1 cm, or would both undergo US follow-up and be smaller than 1 cm. Adjusting size thresholds to decrease the number of missed malignant nodules that are 1 cm or larger would result in a substantial increase in the number of benign nodules undergoing follow-up.

Thyroid follicular microcarcinoma

Differentiated thyroid cancers are the most common malignancies arising in thyroid gland. Papillary thyroid cancer presents a very favorable prognosis, while follicular type is slightly more aggressive, mainly for its attitude to hematogenous spreading with distant metastases. Papillary microcarcinoma (10 mm or less) has an excellent prognosis, largely demonstrated, and its management is changed in the last few years, reducing surgical procedure, role of radio iodine ablation (RAI) and TSH suppression. But no effective data are available for follicular thyroid microcarcinoma (mFTC); very few reports and studies are present in literature about mFTC, mainly for its low incidence. Aim of this paper is to review current literature to reach, in absence of evidence, some suggestion in managing mFTC.

Comparative study on operative trauma between microwave ablation and surgical treatment for papillary thyroid microcarcinoma

AIM

To compare the effect and postoperative trauma of ultrasound-guided percutaneous microwave ablation and surgical resection in the treatment of papillary thyroid microcarcinoma (PTMC).

METHODS

Eighty-seven patients with PTMC treated at Fudan University affiliated Shanghai Fifth People’s Hospital were enrolled as subjects. The patients were divided into a microwave ablation group (41 cases) and a surgical group (46 cases). The operative time, intraoperative blood loss, length of hospital stay, serum C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), thyroid-related hormonal changes, and complications 7 d and 30 d after surgery were observed.

RESULTS

The operative time, intraoperative blood loss, and length of hospital stay in the surgical group were significantly higher than those in the microwave ablation group (P < 0.05). The levels of CRP, IL-6, and TNF-α in the surgical group were significantly higher than those in the microwave ablation group (P < 0.05). The free triiodothyronine (FT3) and free thyroxin (FT4) levels in the surgical group were significantly lower than those in the microwave ablation group (P < 0.05). However, the postoperative thyroid stimulating hormone (TSH) level was significantly higher than that in the microwave ablation group (P < 0.05). There were significant interactions between the FT3, FT4, and TSH 7 d and 30 d after operation and the treatment methods (P < 0.05). There was no significant difference in the complications between the two groups (P > 0.05).

CONCLUSION

Microwave ablation for papillary microcarcinoma of the thyroid gland has less trauma to the body, quicker recovery, and no scars. It can effectively shorten the length of hospital stay and improve the quality of life of patients.

Too Much of a Good Thing: Radioactive Iodine Ablation Use for Micropapillary Thyroid Carcinoma

Radioactive iodine (RAI) is not routinely recommended for the adjuvant treatment of micro-papillary thyroid carcinoma (MPTC). We aimed to report on clinical and pathologic factors associated with the use of RAI in these patients. We queried the Surveillance, Epidemiology, and End Results database for patients who underwent surgery for MPTC (tumor size ≤1 cm) from 1988 to 2009. We excluded patients without a biopsy-proven diagnosis, those diagnosed at autopsy, and patients with documented extra-thyroidal extension. Multivariate logistic regression models predicted the use of RAI based on patient, tumor, and treatment-related factors. We identified 24,076 patients with MPTC that were eligible for study inclusion. Of these, 6,172 (25.6%) received RAI. Lymph node metastases were present in 23.8 per cent of those for whom lymph node status was known. On multivariate analysis, an increasing number of positive nodes, increasing tumor size, Asian race, and male gender predicted the use of RAI. RAI use was less likely in those with advancing age, an increasing number of lymph nodes examined and patients that received less than a total thyroidectomy. Among node-negative patients, Asian race and increasing tumor size predicted the use of RAI. Factors predicting decreased use of RAI were an increasing number of lymph nodes examined, unknown race, less than a total thyroidectomy, and advancing age. A significant number of MPTC patients receive potentially unnecessary RAI.

Preoperatively undiagnosed papillary thyroid carcinoma in patients thyroidectomized for benign multinodular goiter

OBJECTIVE

Incidental thyroid cancers (ITCs) are often microcarcinomas; among them, the most frequent histotype is the papillary one. The purpose of this study was to evaluate the rate of papillary thyroid cancer (PTC) in patients thyroidectomized for benign multinodular goiter.

SUBJECT AND METHODS

We retrospectively evaluated the histological incidence of PTC in 207 consecutive patients who, in a 1-year period, underwent thyroidectomy for benign multinodular goiter. All patients came from an iodine-deficient area (Orleans, France) with three nuclear power stations located in the neighboring areas of the county town.

RESULTS

Overall, 25 thyroids (12.1%) harbored 37 PTC, of which 31 were microcarcinomas. In these 25 PTC patients, mean age was 55 ± 10 years (range 30-75), female:male ratio 20:5 (4:1). In 10 patients (40% of 25 and 4.8% of 207), PTCs were bilateral, and in 7 (2 with microPTCs) the thyroid capsule was infiltrated. These 7 patients underwent central and lateral cervical lymph node dissections, which revealed lymph node metastases in one and two cases, respectively. Radioiodine treatment was performed in 7 cases. Neither mortality nor transient and permanent nerve injuries were observed. Four (16%) transient hypocalcaemias occurred as early complications. At last follow-up visit (mean length of follow-up 17.2 ± 3.4 months), all patients were doing well and free of any clinical local recurrence or distant metastases.

CONCLUSION

With a 12% risk that multinodular goiter harbors preoperatively unsuspected PTCs, which can have already infiltrated the capsule and that can be accompanied by PTC foci contralaterally, an adequate surgical approach has to be considered.

Epidemiological trends of hormone-related cancers in Slovenia

The incidence of hormone-related cancers tends to be higher in the developed world than in other countries. In Slovenia, six hormone-related cancers (breast, ovarian, endometrial, prostate, testicular, and thyroid) account for a quarter of all cancers. Their incidence goes up each year, breast and prostate cancer in particular. The age at diagnosis is not decreasing for any of the analysed cancer types. The risk of breast cancer is higher in the western part of the country, but no differences in geographical distribution have been observed for other hormone-related cancers. Furthermore, areas polluted with endocrine-disrupting chemicals that affect hormone balance such as PCBs, dioxins, heavy metals, and pesticides, do not seem to involve a greater cancer risk. We know little about how many cancers can be associated with endocrine disruptors, as there are too few reliable exposure studies to support an association.

Association between p16 Promoter Methylation and Thyroid Cancer Risk: A Meta-analysis

BACKGROUND

The aim of the meta-analysis was to derive a more precise assessment of the association between p16 promoter methylation and thyroid cancer risk.

MATERIALS AND METHODS

The PubMed, Web of Science databases and Chinese CNKI were searched for relevant articles. Ultimately, seventeen case-control studies were included with a total of 804 thyroid cancer cases and 487 controls analysis by R Software (R version 3.1.2) including meta. Crude odds ratios with 95% confidence intervals were calculated using the random-effects model which were used to assess the strength of relationship between p16 methylation and lung carcinogenesis. Funnel plots were carried out to evaluate publication bias.

RESULTS

The meta-analysis results showed that the frequency of p16 promoter methylation in cancer tissue/blood was significantly higher than that normal tissue/ blood (OR=5.46, 95%CI 3.12-9.55, P<0.0001) by random effects model with small heterogeneity.

CONCLUSIONS

Thus, p16 promoter methylation may be associated with thyroid cancer risk.

Alcohol Intake and Risk of Thyroid Cancer: A Meta-Analysis of Observational Studies

Purpose

The purpose of this study was to assess whether alcohol intake is associated with the risk of thyroid cancer by a meta-analysis of observational studies.

Materials and Methods

We searched PubMed and EMBASE in June of 2015 to locate eligible studies. We included observational studies such as cross-sectional studies, case-control studies, and cohort studies reporting odd ratios (ORs) or relative risk (RRs) with 95% confidence intervals (CIs).

Results

We included 33 observational studies with two cross-sectional studies, 20 case-controls studies, and 11 cohort studies, which involved a total of 7,725 thyroid cancer patients and 3,113,679 participants without thyroid cancer in the final analysis. In the fixed-effect model meta-analysis of all 33 studies, we found that alcohol intake was consistently associated with a decreased risk of thyroid cancer (OR or RR, 0.74; 95% CI, 0.67 to 0.83; I²=38.6%). In the subgroup meta-analysis by type of study, alcohol intake also decreased the risk of thyroid cancer in both case-control studies (OR, 0.77; 95% CI, 0.65 to 0.92; I²=29.5%; n=20) and cohort studies (RR, 0.70; 95% CI, 0.60 to 0.82; I²=0%; n=11). Moreover, subgroup meta-analyses by type of thyroid cancer, gender, amount of alcohol consumed, and methodological quality of study showed that alcohol intake was significantly associated with a decreased risk of thyroid cancer.

Conclusion

The current meta-analysis of observational studies found that, unlike most of other types of cancer, alcohol intake decreased the risk of thyroid cancer.

Detection of Tumor Multifocality Is Important for Prediction of Tumor Recurrence in Papillary Thyroid Microcarcinoma: A Retrospective Study and Meta-Analysis

Background:

The clinicopathological characteristics and conclusive treatment modality for multifocal papillary thyroid microcarcinoma (mPTMC) have not been fully established.

Methods:

A retrospective study, systematic review, and meta-analysis were conducted to elucidate the clinicopathological significance of mPTMC. We investigated the multiplicity of 383 classical papillary thyroid microcarcinomas (PTMCs) and the clinicopathological significance of incidental mPTMCs. Correlation between tumor recurrence and multifocality in PTMCs was evaluated through a systematic review and meta-analysis.

Results:

Tumor multifocality was identified in 103 of 383 PTMCs (26.9%). On linear regression analysis, primary tumor diameter was significantly correlated with tumor number (R²=0.014, p=.021) and supplemental tumor diameter (R²=0.117, p=.023). Of 103 mPTMCs, 61 (59.2%) were non-incidental, with tumor detected on preoperative ultrasonography, and 42 (40.8%) were diagnosed (incidental mPTMCs) on pathological examination. Lymph node metastasis and higher tumor stage were significantly correlated with tumor multifocality. However, there was no difference in nodal metastasis or tumor stage between incidental and non-incidental mPTMCs. On meta-analysis, tumor multifocality was significantly correlated with tumor recurrence in PTMCs (odds ratio, 2.002; 95% confidence interval, 1.475 to 2.719, p<.001).

Conclusions:

Our results show that tumor multifocality in PTMC, regardless of manner of detection, is significantly correlated with aggressive tumor behavior.

BRAF V600E and decreased NIS and TPO expression are associated with aggressiveness of a subgroup of papillary thyroid microcarcinoma

BACKGROUND

Thyroid cancer incidence has dramatically increased worldwide over the last two decades. The rise is mostly due to an increased detection of small papillary thyroid carcinomas (PTCs) (≤20  mm), predominantly microPTC (≤10  mm). Although small tumors generally have an excellent outcome, a considerable percentage may have a more aggressive disease and worse prognosis. The clinical challenge is to preoperatively identify those tumors that are more likely to recur.

AIM

To improve risk stratification and patient management, we sought to determine the prognostic value of BRAF V600E, NRAS or RET/PTC mutations in patients with PTC measuring <20  mm, mainly microPTC.

METHODS

The prevalence of RET/PTC fusion genes was examined by quantitative RT-PCR. BRAF V600E and NRAS Q61 mutations were determined by PCR sequencing. To further elucidate why some small PTC are less responsive to radioactive iodine treatment therapy, we explored if these genetic alterations may modulate the expression of iodine metabolism genes (NIS, TPO, TG, TSHR and PDS) and correlated with clinico-pathological findings that are predictors of recurrence.

RESULTS

This study shows that tumors measuring ≤20  mm exhibited higher prevalence of BRAF V600E mutation, which correlated with aggressive histopathological parameters, higher risk of recurrence, and lower expression of NIS and TPO. Although this correlation was not found when microPTC were evaluated, we show that tumors measuring 7-10  mm, which were positive for BRAF mutation, presented more aggressive features and lower expression of NIS and TPO.

CONCLUSION

We believe that our findings will help to decide the realistic usefulness of BRAF V600E mutation as a preoperative marker of poor prognosis in small PTC, primarily in microPTC.

Characteristics and Survival of Breast Cancer Patients with Multiple Synchronous or Metachronous Primary Cancers

PURPOSE

Newly developed extra-mammary multiple primary cancers (MPCs) are an issue of concern when considering the management of breast cancer survivors. This study aimed to investigate the prevalence of MPCs and to evaluate the implications of MPCs on the survival of breast cancer patients.

MATERIALS AND METHODS

A total of 8204 patients who underwent surgery at Severance Hospital between 1990 and 2012 were retrospectively selected. Clinicopathologic features and survival over follow-up periods of ≤5 and >5 years were investigated using univariate and multivariate analyses.

RESULTS

During a mean follow-up of 67.3 months, 962 MPCs in 858 patients (10.5%) were detected. Synchronous and metachronous MPCs were identified in 23.8% and 79.0% of patients, respectively. Thyroid cancer was the most prevalent, and the second most common was gynecologic cancer. At ≤5 years, patients with MPCs were older and demonstrated significantly worse survival despite a higher proportion of patients with lower-stage MPCs. Nevertheless, an increased risk of death in patients with MPCs did not reach statistical significance at >5 years. The causes of death in many of the patients with MPCs were not related to breast cancer. Stage-matched analysis revealed that the implications of MPCs on survival were more evident in the early stages of breast disease.

CONCLUSION

Breast cancer patients with MPCs showed worse survival, especially when early-stage disease was identified. Therefore, it is necessary to follow screening programs in breast cancer survivors and to establish guidelines for improving prognosis and quality of life.

Thyroid nodules ≤ 5 mm on ultrasonography: are they "leave me alone" lesions?

The incidence of small thyroid malignancy has increased. However, there is no evidence-based guideline for managing thyroid nodules ≤ 5 mm on ultrasonography (US). We evaluated how to manage thyroid nodules ≤ 5 mm. Thyroid nodules ≤ 5 mm in size on US that had undergone surgery and US-guided fine-needle aspiration were eligible. A total of 3,117 thyroid nodules in 3,012 patients were included. The size changes of malignant and benign nodules during follow-up were evaluated. Thyroid malignancies were classified according to follow-up and surgery time within and after 12 months. Clinico-pathological characteristics were compared. Of 3,117 nodules, 1,639 nodules in 1,619 patients were benign and 1,478 in 1,427 were malignant. Only 5.8 and 1.2 % of malignant nodules and 6.8 and 4.2 % of benign nodules increased in size when a 2-mm and 3-mm change on US were referenced. Of 1,079 patients with an index malignancy ≤ 5 mm, extrathyroidal extension, lymph node metastasis, recurrence, and mortality were not significantly different between patients with and without follow-up and between patients with surgery within 12 months and after 12 months. None of the patients who underwent surgery had distant metastasis and none died of thyroid malignancy. In thyroid nodules ≤ 5 mm found on US, US-FNA could be recommended in cases of increased size during US follow-up if lateral LNM was not found because a delay in surgery did not impact cancer recurrence and mortality.

Examining the Bethesda criteria risk stratification of thyroid nodules

BACKGROUND

The Bethesda criteria are proposed for appropriate stratification of malignancy risk in thyroid nodules, but controversy exists regarding their accuracy and reliability in decision making. Additionally, previous studies have suggested higher rates of both malignancy and false negative fine needle aspiration biopsy (FNA) associated with increasing nodule size. This study aims to determine the accuracy of ultrasound (US)-guided FNA using the current Bethesda criteria in surgical practice. We also aimed to investigate the relationship between nodule size and malignancy.

METHODS

A retrospective analysis of US-guided FNAs by a single surgeon during a 4.5 year period. FNA results using Bethesda criteria were compared to final surgical pathology.

RESULTS

611 patients with thyroid nodules underwent US-guided FNA. FNA results in 375 subsequently excised thyroid nodules were recorded according to the Bethesda criteria: 192 (51%) benign, 65 (17%) atypia of unknown significance/follicular lesion of undetermined significance (AUS/FLUS), 42 (11%), suspicious for follicular neoplasm (SFN), 17 (5%) suspicious for malignancy (SM), 28 (8%) malignancy, and 31 (8%) non-diagnostic. Malignancy was confirmed by surgical pathology in 15%, 34%, 50%, 88%, 100%, and 39% of the above groups respectively. Sensitivity, specificity, and false-negative rate were 61%, 99%, and 15% respectively. No correlation existed between the size of nodules with indeterminate FNA results and malignancy rate (p=0.89), or size of nodules with non-diagnostic FNA and malignancy rate (p=0.50).

CONCLUSION

The current Bethesda risk stratification system underestimated malignancy rates in benign, indeterminate and non-diagnostic cytopathologic categories in our experience. There was no positive linear correlation between nodule size and malignancy rate in these cytopathologic categories.

A review of the Fukushima nuclear reactor accident: radiation effects on the thyroid and strategies for prevention

PURPOSE OF REVIEW

This is a summary of the nuclear accident at the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Stations (FDNPS) on 11 March 2011 to be used as a review of the radiation effects to the thyroid and strategies of prevention.

RECENT FINDINGS

The amount of radioiodine released to the environment following the Fukushima accident was 120 Peta Becquerel, which is approximately one-tenth of that in the Chernobyl accident. Residents near the FDNPS were evacuated within a few days and foodstuffs were controlled within 1 or 2 weeks. Therefore, thyroid radiation doses were less than 100 mSv (intervention levels for stable iodine administration) in the majority of children, including less than 1 year olds, living in the evacuation areas. Because the incidence of childhood thyroid cancer increased in those residing near the site following the Chernobyl accident, thyroid screening of all children (0-18 years old) in the Fukushima Prefecture was started. To date, screening of more than 280 000 children has resulted in the diagnosis of thyroid cancer in 90 children (approximate incidence, 313 per million). Thus, although the dose of radiation was much lower, the incidence of thyroid cancer appears to be much higher than that following the Chernobyl accident.

SUMMARY

A comparison of the thyroidal consequences following the Fukushima and Chernobyl nuclear reactor accidents is discussed. We also summarize the recent increased incidence in thyroid cancer in the Fukushima area following the accident in relation to increased thyroid ultrasound screening and the use of advanced ultrasound techniques.

VIDEO ABSTRACT

http://links.lww.com/COE/A8.

Can increased tumoral vascularity be a quantitative predicting factor of lymph node metastasis in papillary thyroid microcarcinoma?

The aim of the present study was to evaluate the clinical implications of the vascular index (VI) as a predicting factor for central and lateral lymph node metastasis (LNM) in patients with papillary thyroid microcarcinoma (PTMC). From January 2011 to October 2011, 588 patients (495 females, 93 males) who were diagnosed with PTMC were included. Clinicopathologic characteristics of patients and ultrasound (US) features of the lesions including VI were evaluated retrospectively. The VI was measured with QLAB 7.0 quantification software using preoperative Doppler US images. Univariate and multivariate analysis were used to assess predictive factors of LNM. From 588 patients, 140 patients (23.8 %) had central LNM and 26 patients (4.4 %) had lateral LNM on pathologic results. The presence of lateral LNM [odds ratio (OR) 5.46; 95 % confidence interval (CI) = 2.19-13.64], bilaterality (OR 2.16; 95 % CI 1.17-4.01), and increased tumor size (OR 1.15; 95 % CI 1.04-1.28) were significant independent factors for predicting central LNM. The presence of central LNM (OR 5.58; 95 % CI 2.22-14.04), upper third location of malignancy (OR 2.50; 95 % CI 1.01-6.21), and tumor size (OR 1.34; 95 % CI 1.03-1.73) were significant independent factors for predicting lateral LNM. However, the VI was not a significant predicting factor for both central and lateral LNM. Therefore, the VI of PTMC may not be useful for predicting central and lateral LNM in patients with PTMC.

Taller-than-wide sign for predicting thyroid microcarcinoma: comparison and combination of two ultrasonographic planes

The aims of this study were to investigate the accuracy of using the taller-than-wide (TTW) sign in two ultrasonographic planes to predict thyroid microcarcinoma, and to confirm the hypothesis that the presence of a TTW sign in both the transverse and longitudinal ultrasonographic planes strongly suggests thyroid microcarcinoma. Nine hundred forty-two thyroid nodules ≤1 cm were submitted to surgical-histopathologic and ultrasonographic examination. TTW signs were divided into three types based on their detection only in the transverse plane (TTTW type, n = 100), only in the longitudinal plane (LTTW type, n = 61) or in both planes (BTTW type, n = 131). The areas under the receiver operating characteristic curves (A(z)) for the three different TTW signs, as well as for the combination of all TTW signs (ATTW, n = 292), were compared. The results indicated that the A(z) values of the TTTW, LTTW, BTTW and ATTW signs in predicting thyroid microcarcinoma were 0.544, 0.531, 0.627 and 0.702, respectively. The ATTW sign was the most accurate (p < 0.05), and the BTTW sign was 100% accurate for predicting thyroid microcarcinoma. However, there was no significant difference between the A(z) values for the TTTW and LTTW signs (p > 0.05). Therefore, both the LTTW and TTTW signs are reliable markers of thyroid microcarcinoma. The BTTW sign strongly suggests thyroid microcarcinoma.

Papillary thyroid microcarcinomas are different from latent papillary thyroid carcinomas at autopsy

The aim of this study was to review the literature of latent papillary thyroid carcinomas (PTCs) discovered at autopsy and describe the available pathologic and demographic differences from a group of papillary thyroid microcarcinomas (PTMCs) the reported in a previous publication. We searched the PubMed for published articles describing latent thyroid carcinomas detected at autopsy. Meta-analysis was performed to identify differences between the clinicopathologic features of PTMCs analyzed previously in our institution (Group I) and those of latent PTCs described in autopsy studies (Group II). We identified 1,355 patients with PTMC (Group I) and 989 with latent PTCs (Group II). Mean patient age was 47.3 yr in Group I and 64.5 yr in Group II. The male:female ratio was 1:10.9 in Group I and 1:1 in Group II. Most PTMCs (67.6%) were larger than 0.5 cm in size, whereas most latent PTCs were <1-3 mm in diameter. The rates of multifocality were 24.7% in Group I and 30.5% in Group II, and the rates of cervical lymph node metastasis were 33.4% in Group I and 10.0% in Group II. Currently available data indicated that clinically evident PTMCs differ from latent PTCs detected at autopsy. Therefore, these two entities should be regarded as different.

Heterogeneous echogenicity of the thyroid parenchyma does not influence the detection of multi-focality in papillary thyroid carcinoma on preoperative ultrasound staging

Heterogeneous echogenicity and micro-nodulations of diffuse thyroid disease on ultrasonography (US) might influence the diagnostic performance of pre-operative US staging, especially the detection of multi-focality. This study was designed to determine whether heterogeneous echogenicity of the thyroid parenchyma influences the diagnostic performance of US in the detection of multi-focality in papillary thyroid carcinoma. Between December 2010 and April 2011, 811 patients underwent pre-operative staging US for papillary thyroid carcinoma and surgery. Twelve radiologists performed the pre-operative US for T and N staging. Underlying parenchymal echogenicity and unilateral and bilateral multi-focality of the thyroid nodules were also evaluated. Patients were divided into two groups on the basis of the underlying echogenicity of the thyroid gland. To evaluate the diagnostic accuracy of US with respect to underlying echogenicity, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated and compared between the two groups. Among the 811 patients included, US revealed underlying heterogeneous echogenicity of the thyroid parenchyma in 204 (25.2%) and underlying homogeneous echogenicity of the thyroid parenchyma in 607 (74.8%). There were no significant differences between the two groups in the diagnostic performance of pre-operative staging US in predicting unilateral multi-focality and bilaterality. Underlying heterogeneous echogenicity in a thyroid gland with Hashimoto's thyroiditis does not significantly influence the detection of multi-focality in papillary thyroid cancer on pre-operative US staging.

Papillary thyroid microcarcinoma: how to diagnose and manage this epidemic?

The incidence of papillary thyroid microcarcinoma (PTmC) has been increasing everywhere due to the improvement of imaging and morphological diagnoses and probably also due to environmental alterations. Despite this, the mortality caused by thyroid cancer has not increased, reflecting the low clinical aggressiveness of most papillary thyroid carcinomas (PTCs) and the quality of the available treatment. The criteria used to classify PTmC remain questionable, making the clinical risk evaluation of these lesions very difficult. There is no solid basis for establishing the most appropriate tumor size (currently <10 mm) to distinguish PTmC from PTC. Moreover, PTmCs encompass all sorts of PTC histotypes, thus turning the whole group of PTmC genetically and biologically heterogeneous. In this review, we address the 2 most interesting issues from a practical standpoint: Are there any specific morphological or molecular features distinguishing PTmC from PTC? Is it possible to predict the clinical behavior of PTmC in fine needle aspiration biopsy and in surgical specimens, using morphological and/or molecular markers?

Current controversies in the initial post-surgical radioactive iodine therapy for thyroid cancer: a narrative review

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy and the fifth most common cancer in women. DTC therapy requires a multimodal approach, including surgery, which is beyond the scope of this paper. However, for over 50 years, the post-operative management of the DTC post-thyroidectomy patient has included radioactive iodine (RAI) ablation and/or therapy. Before 2000, a typical RAI post-operative dose recommendation was 100 mCi for remnant ablation, 150 mCi for locoregional nodal disease, and 175-200 mCi for distant metastases. Recent recommendations have been made to decrease the dose in order to limit the perceived adverse effects of RAI including salivary gland dysfunction and inducing secondary primary malignancies. A significant controversy has thus arisen regarding the use of RAI, particularly in the management of the low-risk DTC patient. This debate includes the definition of the low-risk patient, RAI dose selection, and whether or not RAI is needed in all patients. To allow the reader to form an opinion regarding post-operative RAI therapy in DTC, a literature review of the risks and benefits is presented.

Appropriate and accurate diagnosis of thyroid nodules: a review of thyroid fine-needle aspiration

Thyroid nodules are clinically palpable in 4-7% of adults in the United States. With ultrasound examination, thyroid nodules are identified in up to 70% of adults. In asymptomatic individuals, the potential for malignancy underlies the clinical importance of investigating thyroid nodules. Increased diagnostic accuracy has improved non-operative management of benign thyroid lesions. Appropriate management of thyroid microcarcinoma and large nodules remains a topic of debate. False-negative FNA cytology remains a concern for clinicians treating patients with thyroid nodules. Due to the challenge of interpreting FNA cytology and recent changes to the cytopathologic classification system, we reviewed the current literature on diagnosis of thyroid nodules using the recent Bethesda criteria.

Worldwide increasing incidence of thyroid cancer: update on epidemiology and risk factors

Background. In the last decades, thyroid cancer incidence has continuously and sharply increased all over the world. This review analyzes the possible reasons of this increase. Summary. Many experts believe that the increased incidence of thyroid cancer is apparent, because of the increased detection of small cancers in the preclinical stage. However, a true increase is also possible, as suggested by the observation that large tumors have also increased and gender differences and birth cohort effects are present. Moreover, thyroid cancer mortality, in spite of earlier diagnosis and better treatment, has not decreased but is rather increasing. Therefore, some environmental carcinogens in the industrialized lifestyle may have specifically affected the thyroid. Among potential carcinogens, the increased exposure to medical radiations is the most likely risk factor. Other factors specific for the thyroid like increased iodine intake and increased prevalence of chronic autoimmune thyroiditis cannot be excluded, while other factors like the increasing prevalence of obesity are not specific for the thyroid. Conclusions. The increased incidence of thyroid cancer is most likely due to a combination of an apparent increase due to more sensitive diagnostic procedures and of a true increase, a possible consequence of increased population exposure to radiation and to other still unrecognized carcinogens.