High Prevalence of Occult Papillary Thyroid Carcinoma in a Surgical Series for Benign Thyroid Disease

Incidence, detection and outcome of differentiated thyroid cancer in Western Sweden

Background

It is unclear whether the increasing incidence of thyroid cancer (TC) due to increased diagnosis of small and indolent tumours might mask a real increase of clinically significant cancers. The aim of this study was to correlate surgery, pathology and outcome data of individual patients to the mode of primary detection (palpation, by imaging or incidental) to assess if TC incidence has increased.

Methods

The Swedish Cancer Registry identified all patients with TC in Västra Götaland County representing approximately 1.6 million inhabitants. Clinical information was retrieved from medical records of patient cohorts from three study intervals (2001–2002, 2006–2007 and 2011–2014) comprising 60 per cent of all TC patients. Data were also obtained from the NORDCAN registry to compare of TC incidence with other Nordic countries.

Results

Between 2001 and 2014, the annualized standard incidence rate/100 000 population (ASR) of TC increased from 3.14 to 10.71 in women and from 1.12 to 3.77 in men. This was higher than the mean incidence for Sweden but similar to that in Norway and Finland. Differentiated TC (DTC) increased more than threefold. The majority of tumours (64 per cent) were detected by palpation. Larger tumours (10–20, 21–40 and greater than 40 mm) increased as much as microcarcinomas (less than 10 mm). Only 5 per cent of the tumours were detected by imaging. All disease-specific deaths (8.5 per cent of DTC in the first two cohorts) and most patients with recurrent or persistent disease (6.6 per cent of DTC cases) were diagnosed due to tumour-related symptoms.

Conclusion

DTC in Western Sweden gradually increased between 2001 and 2014. The majority of tumours were detected by palpation suggesting a real increase in the incidence of clinically significant thyroid malignancies.

Active surveillance for patients with very low-risk thyroid cancer

Over the past 30 years in the United States, increasing identification of small thyroid nodules has led to a dramatic rise in the detection of small thyroid cancers, many of which are unlikely to progress to overt clinical disease. Because autopsy studies reveal that up to 30% of people harbor clinically occult thyroid cancers, the growing use of diagnostic technologies has identified an increasing number of small, clinically low risk papillary thyroid cancers (PTCs). In recent years, clinical practice has evolved to de-intensify the treatment for PTCs, with fewer total thyroidectomy and nodal dissection procedures being performed, in favor of more limited operations. In addition, vigilant observation of selected low risk cancers has demonstrated outcomes comparable to those patients who undergo immediate surgical intervention. Active surveillance has emerged as a new option within the treatment algorithm of PTCs. There is now robust data from cancer centers in Japan and Korea which have reported excellent oncologic outcomes among patients undergoing active surveillance for PTC, as well as more recent, similar data from the United States. American Thyroid Association guidelines now include the option of active surveillance for appropriately selected patients with low-risk PTC. With active surveillance now one option within the standard of care for patients with certain thyroid cancers, surgeons have become critical to facilitating shared decision-making for patients facing this diagnosis.

Geographic influences in the global rise of thyroid cancer

The incidence of thyroid cancer is on the rise, and this disease is projected to become the fourth leading type of cancer across the globe. From 1990 to 2013, the global age-standardized incidence rate of thyroid cancer increased by 20%. This global rise in incidence has been attributed to several factors, including increased detection of early tumours, the elevated prevalence of modifiable individual risk factors (for example, obesity) and increased exposure to environmental risk factors (for example, iodine levels). In this Review, we explore proven and novel hypotheses for how modifiable risk factors and environmental exposures might be driving the worldwide increase in the incidence of thyroid cancer. Although overscreening and the increased diagnosis of possibly clinically insignificant disease might have a role in certain parts of the world, other areas could be experiencing a true increase in incidence due to elevated exposure risks. In the current era of personalized medicine, national and international registry data should be applied to identify populations who are at increased risk for the development of thyroid cancer.

Hyperthyroidism and Concurrent Thyroid Cancer

Aims and Background

The aim of this study was to analyze the frequency of coexisting hyperthyroidism and thyroid malignancy in endemic goiter areas and review the current literature on the subject.

Methods

During the period January 1984 to June 1998, 1853 patients were examined for hyperthyroidism at the Spedali Civili Hospital of Brescia, Italy; 512 (27.6%) subjects underwent surgery. Of these patients 108 (21%) had Graves’ disease, 251 (49%) multinodular toxic goiter (MTG) and 153 (30%) uninodular toxic goiter (UTG).

Results

Malignancy was found in 24 (4.7%) patients: 19 females and 5 males with a mean age of 52.2 years (range, 21-76 years). The frequency of cancer in Graves’ disease was 6.4%, 5 females and 2 males; in MTG 3.9%, 2 females and 8 males, and in UTG 4.4%, 7 females and 1 male.

Conclusions

Our data confirm previous reports on the frequency of thyroid cancer in hyperthyroidism. This association is more relevant than previously suspected. The frequent coexistence of hyperthyroidism and neoplasia, demonstrated by our study and the most recent literature, underlines the importance of studying and excluding the possibility of neoplastic degeneration by means of a systematic approach.

Frequency of Thyroid Carcinoma in a Recent Series of 539 Consecutive Thyroidectomies for Multinodular Goiter

Aims and background

The aim of the study was to analyze the frequency of thyroid carcinoma in a consecutive series of 539 thyroidectomies for multinodular goiter (MNG) and to assess the influence of sex and age as cancer risk factors.

Methods

In a 2-year period, 539 patients underwent subtotal or total thyroidectomy for MNG at the Institute of General Surgery, University of Padova, Padova, Italy: 455 were females and 84 males (F/M = 5.5/1); mean age was 46 years (min. 17, max 78). Only 17 patients (3.1%) (16 females and 1 male) were aged 21 years or less.

Results

A malignancy was found in 41 patients: 38 females and 3 males; 39 older and 2 younger than 21 years. The frequency of cancer in MNG was 7.6%: 8.3% in females and 3.6% in males; 7.5% in patients older than 21 and 11.7% under 21 years.

Conclusions

The combination of MNG and carcinoma should always be carefully considered but not overemphasized, and the policy of surgically treating all patients with MNG is not justified. Sex and age cannot be considered as factors of a higher risk of cancer.

Levothyroxine or minimally invasive therapies for benign thyroid nodules

BACKGROUND

Thyroid nodules (TN) are common in the adult population. Some physicians use suppressive levothyroxine (LT4) therapy to achieve a reduction in the number and volume of TN. In addition, minimally invasive treatments, such as percutaneous ethanol injection (PEI) sclerotherapy, laser photocoagulation (LP), and microwave (MW), radiofrequency (RF) and high-intensity focused ultrasound (HIFU) ablation, have been proposed, especially for pressure symptoms and cosmetic complaints, as an alternative to surgery. However, the risk to benefit ratio of all treatments for benign TN is currently unknown.

OBJECTIVES

To assess the effects of LT4 or minimally invasive therapies (PEI, LP, and RF/HIFU/MW ablation) on benign TN.

SEARCH METHODS

We identified studies from computerised searches of The Cochrane Library, MEDLINE, EMBASE and LILACS (all performed up to April 2014). We also searched trial registers, examined reference lists of included randomised controlled trials (RCTs) and systematic reviews, and contacted study authors.

SELECTION CRITERIA

We included studies if they were RCTs of LT4, PEI, LP, RF, HIFU or MW therapy in participants with an established diagnosis of benign TN. We excluded trials investigating the prevention of recurrence of thyroid disease after surgery, irradiation or treatment with radioiodine.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, assessed studies for risk of bias and evaluated overall study quality utilising the GRADE instrument. We assessed the statistical heterogeneity of included studies by visually inspecting forest plots and quantifying the diversity using the I² statistic. We synthesised data using random-effects model meta-analysis or descriptive analysis, as appropriate.

MAIN RESULTS

Thirty-one studies randomised 2952 outpatients to investigate the effects of different therapies on benign TN. Studies on LT4, PEI, LP and RF ablation therapy randomised 2083, 607, 192 and 70 participants, respectively. We found no RCTs of HIFU or MW ablation therapy in benign TN. The duration of treatment varied according to the applied therapies: up to five years for LT4 and one to three PEI ablations, one to three LP sessions and one or two RF sessions. Median follow-up was 12 months for LT4 and six months for minimally invasive therapies. Evidence was of low-to-moderate quality, and risk of performance and detection bias for subjective outcomes was high in most trials.No study evaluated all-cause mortality or health-related quality of life. Only one LT4 study provided some data on the development of thyroid cancer, reporting no abnormal cytological findings. One LP study provided limited information on costs of treatment.LT4 compared with no treatment or placebo was associated with a nodule volume reduction of 50% or more in 16% compared with 10% of participants after 6 to 24 months of follow-up (risk ratio (RR) 1.57 (95% confidence interval (CI) 1.04 to 2.38); P = 0.03; 958 participants; 10 studies; moderate-quality evidence). Pressure symptoms or cosmetic complaints were not investigated in LT4 studies. LT4 therapy was generally well tolerated: three studies provided quantitative data on signs and symptoms of hyperthyroidism, which were observed in 25% of LT4-treated versus 7% of placebo-treated participants at 12 to 18 months of follow-up (269 participants; 3 trials; low-quality evidence).PEI compared with cyst aspiration only was associated with a nodule volume reduction of 50% or more in 83% compared with 44% of participants after 1 to 24 months of follow-up (RR 1.83 (95% CI 1.32 to 2.54); P = 0.0003; 105 participants; 3 studies; low-quality evidence). Improvements in neck compression symptoms after 6 to 12 months of follow-up were seen in 78% of participants receiving PEI versus 38% of those in comparator groups. No reliable summary effect estimate could be established, RR ranged from 1.0 to 3.06 in favour of PEI (370 participants; 3 trials; low-quality evidence). In all trials, participants experienced periprocedural cervical tenderness and light-to-moderate pain usually lasting from minutes to several hours. As a result of the PEI procedure, 26% of participants reported slight-to-moderate pain compared with 12% of those receiving cyst aspiration only (RR 1.78 (95% CI 0.62 to 5.12); P = 0.28; 104 participants; 3 studies; low-quality evidence).One study comparing LP with LT4 showed a nodule volume reduction of 50% or more in favour of LP after 12 months of follow-up in 33% of LP participants versus 0% of LT4 participants, respectively (62 participants; 1 trial; low-quality evidence). A total of 82% of LP-treated versus 0% of untreated participants showed improvements in pressure symptoms after 6 to 12 months of follow-up (RR 26.65 (95% CI 5.47 to 129.72); P < 0.0001; 92 participants; 3 trials; low-quality evidence). Around 20% of LP-treated participants reported light-to-moderate cervical pain lasting 48 hours or more (97 participants; 3 trials; low-quality evidence).One trial with 40 participants, comparing RF with no treatment, resulted in a mean nodule volume reduction of 76% in the RF group compared with 0% of those in the no-treatment group at six months of follow-up (low-quality evidence). These RF-treated participants had fewer pressure symptoms and cosmetic complaints after 12 months of follow-up compared with untreated participants (a 2.8 decrease versus a 1.1 increase on a six-point scale, respectively, with higher values indicating more severe symptoms; low-quality evidence). All participants complained of pain and discomfort during RF, which disappeared when the energy was reduced or turned off (low-quality evidence).

AUTHORS' CONCLUSIONS

No study evaluated all-cause mortality, health-related quality of life or provided systematic data on the development of thyroid cancer. Longest follow-up was five years and median follow-up was 12 months. Nodule volume reductions were achieved by PEI, LP and RF, and to a lesser extent, by LT4. However, the clinical relevance of this outcome measure is doubtful. PEI, LP and RF led to improvements in pressure symptoms and cosmetic complaints. Adverse events such as light-to-moderate periprocedural pain were seen after PEI, LP and RF. Future studies should focus on patient-important outcome measures, especially health-related quality of life, and compare minimally invasive procedures with surgery. RCTs with follow-up periods of several years and good-quality observational studies are needed to provide evidence on the development of thyroid cancer, all-cause mortality and long-term adverse events.

Surgical management of thyroid cancer

Thyroid cancer is the most common endocrine neoplasm; however, it only accounts for less than 1% of all human malignances. Thyroid cancers are divided into well differentiated and non-well differentiated cancers, according to their histology and behavior. The surgical management options of well-differentiated thyroid cancer include total or near-total thyroidectomy, subtotal thyroidectomy and lobectomy plus isthmusectomy. The extent of surgery for thyroid cancer continues to be an area of controversy. Complications associated with thyroid surgery are directly proportional to the extent of thyroidectomy and inversely proportional to the experience of the operating surgeon. They occur less frequently with good surgical technique and better understanding of surgical anatomy, and include wound healing and infections (seroma, hematoma and wound infection), nerve injury, hypoparathyroidism, hypothyroidism, postoperative hemorrhage and respiratory obstruction.

Papillary thyroid microcarcinomas: a comparative study of the characteristics and risk factors at presentation in two cancer registries

CONTEXT

Papillary thyroid microcarcinoma (PTMC) is an indolent neoplasia, often asymptomatic and discovered incidentally. Some PTMCs, however, exhibit a more aggressive behavior, frequently recur, and can even cause cancer-related death.

OBJECTIVE

The aim of this study was to evaluate the prevalence of PTMCs and the associated risk factors at presentation in 2 thyroid cancer registries from areas with different genetic and environmental characteristics.

DESIGN AND PATIENTS

We conducted a retrospective, observational study of all incident cases of PTMCs recorded over a 5-year period in the Sicilian Regional Registry for Thyroid Cancer (SRRTC) and in the Surveillance Epidemiology and End Results (SEER) US registry.

SETTING

The study took place at an academic hospital.

RESULTS

The incidence of PTMCs was much higher in Sicily (1777 PTMC diagnosed in 2002-2006; age-standardized incidence rate for the world population [ASRw] = 5.8 per 100 000) than in the United States (14 423 PTMC in the period 2004-2008; ASRw = 2.9 per 100 000). Within the SRRTC, a significantly higher incidence was observed in the volcanic area (ASRw = 10.4 vs 4.6 in the rest of Sicily). In Sicily, the female to male ratio was higher, and PTMC patients were younger. In both registries, a significant inverse correlation was observed between age and tumor size. Young patients (≤45 y) exhibited a higher frequency of nodal metastases.

CONCLUSIONS

PTMC incidence is twice as high in Sicily compared with the United States, and within Sicily, the incidence is twice as high in the volcanic area. In young patients, PTMCs are larger at presentation and exhibit more risk factors. In both registries, more than 35% of PTMCs exhibited 2 or more risk factors, suggesting that they may require surgery and follow-up similar to that of larger carcinomas.

Thyroid microcarcinoma

Nowadays the most commonly occurring differentiated thyroid cancer in many countries is a microcarcinoma in patients older than 45 years, incidentally found during neck ultrasound. In view of their low morbidity and mortality, the crucial point is how to manage such microcarcinomas. Recently published European and American guidelines aim to minimize the diagnostic and therapeutic procedures without affecting the diagnostic accuracy and the therapeutic effectiveness, keeping in mind that we are dealing with patients who have a normal life expectancy and to whom we have to guarantee an excellent quality of life. The present review will summarize the clinical and pathological features of thyroid microcarcinoma, including its definition, prevalence, presentation, pathology, genetic, clinical impact and will try to derive from them a rationale for therapeutic and diagnostic intervention.

Thyroid microcarcinoma

Nowadays the most commonly occurring differentiated thyroid cancer in many countries is a microcarcinoma in patients older than 45 years, incidentally found during neck ultrasound. In view of their low morbidity and mortality, the crucial point is how to manage such microcarcinomas. Recently published European and American guidelines aim to minimize the diagnostic and therapeutic procedures without affecting the diagnostic accuracy and the therapeutic effectiveness, keeping in mind that we are dealing with patients who have a normal life expectancy and to whom we have to guarantee an excellent quality of life. The present review will summarize the clinical and pathological features of thyroid microcarcinoma, including its definition, prevalence, presentation, pathology, genetic, clinical impact and will try to derive from them a rationale for therapeutic and diagnostic intervention.

Managing thyroid microcarcinomas

Papillary thyroid microcarcinomas (PTMCs) are the most common form of classic papillary thyroid carcinoma (PTC). PTMCs are typically discovered by fine-needle- aspiration biopsy (FNAB), usually with sensitive imaging studies, or are found during thyroid surgery in a patient without a previously known history of thyroid carcinoma. However, the definition of PTMC has not always been universally accepted, thus creating controversy concerning the diagnosis and treatment of PTMC. The aim of this review is to summarize the clinical features of PTMC and identify the widely differing opinions concerning the diagnosis and management of these small ubiquitous thyroid tumors.

Incidental Carcinoma in Multinodular Goiter: Risk Factors

The aim of the study was to analyze the frequency of incidental thyroid carcinoma (unknown tumor smaller than or equal to 10 mm) in a consecutive series of 462 total thyroidectomies for multinodular goiter and to investigate the clinical risk factors for this type of malignancy. A retrospective, single-center study of outcome data collected from patients with preoperative diagnosis of multinodular goiter who underwent total thyroidectomy at the General Surgery Unit of Pavia (Italy) between January 2000 and December 2008 was performed. Possible risk factors for malignancy were: gender, age, time of evolution of goiter, presence of a dominant nodule in multinodular goiter, hyperthyroidism, history of radiation to the neck, residence in an area of endemic goiter, prior thyroid surgery, calcifications in the goiter detected by neck ultrasound or chest X-rays, and a family history of thyroid diseases. In a 9-year period, 462 patients underwent total thyroidectomy. We found 41 cases of incidental thyroid carcinoma; the most common histopathological type was papillary. The multivariable analysis demonstrated that the clinical variables associated with occult carcinoma were a personal history of radiation therapy to the neck, the presence of calcifications detected by ultrasound or neck X-rays, and a family history of thyroid diseases; residence in an area of endemic goiter was a protective factor. A personal history of radiation to the neck, detection of calcifications by ultrasound or by neck X-rays, and a family history of thyroid diseases should be considered clinical risk factors for malignancy in multinodular goiter.

A combined molecular-pathologic score improves risk stratification of thyroid papillary microcarcinoma

BACKGROUND

Thyroid papillary microcarcinoma (TPMC) is an incidentally discovered papillary carcinoma that measures ≤1.0 cm in size. Most TPMCs are indolent, whereas some behave aggressively. The objective of the study was to evaluate whether the combination of v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation and specific histopathologic features allows risk stratification of TPMC.

METHODS

A group aggressive TPMCs was selected based on the presence of lymph node metastasis or tumor recurrence. Another group of nonaggressive tumors included TPMCs matched with the first group for age, sex, and tumor size, but with no extrathyroid spread. A molecular analysis was performed, and histologic slides were scored for multiple histopathologic criteria. A separate validation cohort of 40 TPMCs was evaluated.

RESULTS

BRAF mutations were detected in 77% of aggressive TPMCs and in 32% of nonaggressive tumors (P = .001). Several histopathologic features differed significantly between the groups. By using multivariate regression analysis, a molecular-pathologic (MP) score was developed that included BRAF status and 3 histopathologic features: superficial tumor location, intraglandular tumor spread/multifocality, and tumor fibrosis. By adding the histologic criteria to BRAF status, sensitivity was increased from 77% to 96%, and specificity was increased from 68% to 80%. In the independent validation cohort, the MP score stratified tumors into low-risk, moderate-risk, and high-risk groups with the probability of lymph node metastases or tumor recurrence in 0%, 20%, and 60% of patients, respectively.

CONCLUSIONS

BRAF status together with several histopathologic features allowed clinical risk stratification of TPMCs. The combined MP risk stratification model was a better predictor of extrathyroid tumor spread than either mutation or histopathologic findings alone.

Advances in ultrasound for the diagnosis and management of thyroid cancer

BACKGROUND

Ultrasonography (US) is increasingly being employed by endocrinologists and surgeons in the diagnosis and management of patients with thyroid nodules and thyroid cancer. Recent consensus guidelines from the American Thyroid Association highlight the importance of this modality by recommending that patients with thyroid nodules should undergo further evaluation with cervical US to stratify the risk of malignancy. Likewise, ultrasound is advocated for the preoperative and postoperative diagnosis of cervical lymph node metastases.

SUMMARY

This article will summarize the US characteristics that impart a suspicious appearance on thyroid nodules and cervical lymph nodes as well as those findings that are reassuring. Likewise, the indications for thyroid nodule and lymph node fine-needle aspiration will be reviewed. Finally, this article will briefly discuss adjunctive tools in US such as elastography, percutaneous ethanol ablation, and radiofrequency ablation.

CONCLUSIONS

US may be used to help stratify the risk of malignancy in thyroid nodules and cervical lymph nodes. This tool further aids in the diagnosis of malignancy when used in conjunction with fine-needle aspiration. US plays an important role as both a diagnostic and therapeutic tool in the evaluation of patients with neck masses.

Clinical efficacy of fine-needle aspiration biopsy of thyroid nodules in males

BACKGROUND

It has recently been suggested that the use of fine-needle aspiration (FNA) biopsy of thyroid nodules in male patients is associated with an unacceptably high false-negative rate in the detection of thyroid malignancy. We hypothesize that FNA biopsy is an accurate preoperative tool for detecting thyroid cancer in men, and that false negative rates are significantly lower than recently reported.

MATERIALS AND METHODS

A retrospective database analysis was performed on all male patients who underwent thyroid surgery from May 1994 through January 2007 at a single institution. The results of preoperative FNA biopsies were compared with final surgical pathologic results. FNA biopsy results were reported as benign, malignant, inconclusive (i.e., follicular neoplasm), or nondiagnostic; final surgical pathology was reported as benign or malignant.

RESULTS

Of 1205 patients who underwent thyroidectomy, 273 (23%) were male. Preoperative FNA biopsy results were obtained in 60% of these male patients and were read as benign in 45/165 (27%) patients, malignant in 47/165 (28%) patients, inconclusive in 66/165 (40%) patients, and nondiagnostic in 7/165 (4%) patients. In male patients with cytology reported as benign, 3/45 (6.7%) FNAs were determined to be malignant on final pathology.

CONCLUSIONS

Our study determined that FNA biopsy of thyroid nodules in male patients has an acceptably low false-negative rate of 6.7% and is, therefore, an accurate and useful diagnostic tool. We recommend preoperative FNA biopsy for all male patients presenting with thyroid nodules as a standard of practice.

High prevalence of carcinoma in ultrasonography-guided fine needle aspiration cytology of thyroid nodules

OBJECTIVE

The purpose of this study was to assess the rate of malignancy in thyroid nodules incidentally detected at sonography and to determine the diagnostic value of ultrasonography-guided fine needle aspiration cytology (USgFNAC) in thyroid nodules.

METHODS

Five hundred patients (84 men and 416 women) who had thyroid incidentalomas underwent USgFNAC at Konkuk University Hospital between August 2005 and July 2006. Thyroid sonography and guided aspiration was performed on all single nodules and on dominant nodules with suspected malignancy in cases of multinodular goiter.

RESULTS

Five hundred fifty-eight nodules from 500 patients were aspirated using ultrasonography guidance. The USgFNAC results for all patients were as follows: 307 (61.4%) benign, 108 (21.6%) suggestive of malignancy, 56 (11.2%) indeterminate, and 29 (5.8%) inadequate for cytologic diagnosis. The rate of malignancy was significantly higher in women than in men (23.6% in women vs 11.9% in men, p<0.01). Ultrasonographic characteristics that had a significant association with thyroid malignancy included solid echocomponent, hypoechogenecity, ill defined margin, and presence of microcalcifications (p<0.05). Eighty-eight patients underwent surgical resection. The positive predictive value of USgFNAC was 90.2% (74/82), and the accuracy index was 84.1% (74/88). In 80 patients with well-differentiated thyroid carcinoma after surgery, 49% (39/80) had lesions smaller than 1 cm.

CONCLUSION

The rate of malignancy in incidental thyroid nodules on USgFNAC was 21.6%. Ultrasonographic features could be useful in differentiating between benign and malignant nodules.

Clinical features and therapeutic implication of papillary thyroid microcarcinoma

Papillary thyroid microcarcinomas (PTMs) are small tumors (< or =1 cm of diameter) that belong to the well-differentiated low-risk carcinomas of the thyroid, which are characterized by benign behavior, probably of little clinical significance, and do not affect patients' survival. They are found in otherwise normal thyroids or in multinodular goiters with a clinical frequency varying substantially according to different series. Sometimes, PTM may be associated with lymph node metastases at presentation and/or locoregional recurrences during follow-up. Distant metastases are extremely rare, but have been reported. Although deaths related to PTM are almost unknown, PTM raises therapeutic implications. This review addresses the issue of definition, treatment, and follow-up of PTM.

Treatment for microcarcinoma of the thyroid--clinical experience

AIMS AND BACKGROUND

Papillary microcarcinoma of the thyroid is a specific subgroup of papillary thyroid carcinoma (PTC) and account for up to 30% of all PTC. According to the World Health Organization, papillary microcarcinoma of the thyroid (PMC) is defined as a papillary thyroid carcinoma measuring <or=10 mm in the greatest dimension. The relative rate of PMC is increasing in patients with differentiated thyroid carcinoma (DTC) mainly due to more frequent use and improvement of ultrasonography and fine-needle aspiration biopsy, and also more accurate histopathological examination of surgical specimens. The high incidence of PMC found in autopsy studies (up to 35%) suggests that most of them have a benign behavior. The locoregional recurrence has been reported in up to 20% of PMC patients and several cases of distant metastases have also been described. The 'ideal' therapeutic approach in PMC patients remains a subject of debate among endocrinologists and surgeons. Treatment of PMC in different departments varies from partial thyroidectomy to total thyroidectomy and radioiodine treatment. The main question in this group of patients is "How should PMC patients be treated?" The aim of this study was to investigate retrospectively the frequency and clinical behavior of PMC of the thyroid gland in our department and also to identify the optimal treatment of this group of patients.

MATERIALS AND METHODS

For this retrospective study, we evaluated 120 patients with PMC in our department (between 1997 and 2005). The mean age of patients at diagnosis was 43 +/- 13 years (range 17-67 years). The female to male ratio was 87.5% (105 females, 15 males). The mean follow-up period of patients in this study was 45 months (16-84 months). Surgical treatment of patients with PMC in our department consisted of a bilateral total thyroidectomy in 25 patients (21%), and a bilateral near total thyroidectomy in 95 patients (79%). In the evaluation of our patients, multifocal PMC had a relative frequency of 15% (18/120 patients). The patients were informed about the different therapeutic strategies and the possible necessity for more frequent radioiodine treatment to eliminate thyroid remnants. All of the patients in our retrospective study had radioiodine (RAI) ablation therapy for residual thyroid tissue.

RESULTS

All patients received an RAI treatment dose which ranged from 75-150 mCi (2.7-5.5 GBq). Our criteria for ablation are as follows: negative I-131 WBS and very low serum Tg levels (<1 ng/mL). In 112/120 patients (93.3%), the thyroid remnant was ablated with a single dose of I-131 75-150 mCi (2.7-5.5 GBq). A second radioiodine treatment was necessary in 8 patients (7%), because of locoregional recurrence (required mean cumulative doses of 8.2-11 GBq I-131). Locoregional reccurence occurred in 2 patients with unifocal tumor, without capsular invasion or lymph node metastases and in 6 patients with multifocal tumor and/or in patients with capsular invasion or lymph node metastases. After a second radioiodine treatment, all of these 8 patients were ablated. All 120 patients remained free from disease (negative I-131 whole body scan, unmeasurable thyroglobulin levels) after a median follow-up period of 45 months and there was no recorded disease-related mortality.

CONCLUSION

The treatment of patients with PMC should be no different from the treatment of patients with PTC, and thyroidectomy followed by radioiodine therapy may be a possible option for treatment of papillary microcarcinoma.

Incidence of Cancer in Nodular Goitres

Introduction: Nodular goitres occur commonly in the population and this paper aims to determine the incidence of thyroid cancer found in these goitres. Materials and Methods: This is a retrospective, consecutive analysis of the histology of 268 nodular goitres that had been operated on, from 2002 to 2004, in a single tertiary hospital in Singapore. Results: Fifty-seven goitres (21.2%) with multiple nodules were found to contain a malignancy. Forty-four thyroid cancers (77%) were of the papillary type. The mean age of presentation for benign nodular goitres was 47.9 years. The mean age of presentation for malignant thyroid tumours was 49.25 years. Conclusion: The incidence of cancer is significant in nodular goitres and these malignant tumours are usually of the papillary type. Key words: Goitres, Malignancy, Thyroid

Papillary microcarcinomas of the thyroid gland and immunohistochemical analysis of expression of p53 protein in papillary microcarcinomas

Background

Thyroid papillary microcarcinoma (TPM) is defined according to WHO criteria as a thyroid tumor smaller than 1–1.5 cm. TPMs are encountered in 0.5–35.6 % of autopsies or surgical specimens where carcinoma had been unsuspected. The purpose of the present study was to evaluate patients who had TPMs in terms of clinical findings, histopathological features and immunohistochemical evidence of expression of the tumor suppressor gene p53.

Methods

A total of 44 patients with TPMs less than 1.0 cm in diameter were included in the study. The patients were evaluated clinically and the tumors were evaluated in terms of their histopathological and immunohistochemical features, including expression of p53.

Results

The female/male ratio was 2.8/1, and the median age at time of diagnosis was 49 years (range 20–71 years). The maximum diameter of the smallest focus was 0.1 mm, and that of the largest was 10 mm microscopically. The mean diameter of all tumors was 5.7 mm. There was no correlation between tumor size and age or gender. Of the TPMs, 72 % were found in the right lobe, 24 % in the left lobe and 4 % in the isthmus. Fine-needle aspiration biopsy provided the diagnosis of TPM in only 43.2 % of the patients. All patients were treated with surgery, with 20 undergoing conservative surgery, i.e. lobectomy or isthmusectomy, and 24 undergoing total thyroidectomy. Frozen section provided the diagnosis of TPM in only 56.8 % of the patients. We found lymphocytic thyroiditis in 13.6% of patients, follicular variants in 11.9%, capsular invasion in 26.8%, lymph node involvement in 11.9%, soft tissue metastases in the neck in 12.1% and multifocality in 31.7 %, and none of these were related to age or gender (p > 0.05). No distant metastases were observed during approximately 10 years of follow up. We found p53 positivity in 34.5 % of TPM tumors. However, p53 expression was not statistically related to age or gender.

Conclusion

Our findings imply that TPMs may not be entirely innocent since they are associated with signs of poor prognosis such as capsular invasion, multifocal presentation, lymph node involvement and p53 positivity. Therefore, TPMs should be evaluated and followed like classical papillary cancers.

Clinical and histological characteristics of papillary thyroid microcarcinoma: results of a retrospective study in 243 patients

CONTEXT

The recognition of thyroid microcarcinoma has increased due to the widespread use of ultrasound-guided fine-needle aspiration biopsies.

OBJECTIVE

The objective of this study was to describe histological and clinical characteristics of papillary thyroid microcarcinoma (PTMC) less than or equal to 1 cm.

DESIGN

This study was a retrospective cohort.

SETTING

This study was conducted at a university hospital endocrine clinic.

PATIENTS

Over a 9-yr period, 243 consecutive patients with PTMC were studied.

RESULTS

PTMC was an incidental finding at surgery in 21.4% of the PTMC cases. There were no differences in the clinical characteristics between those with incidental PTMC and those with suspected thyroid carcinoma. None of the patients with a cancer less than 8 mm had distant metastases, whereas distant metastases were observed in patients with cancers >/= 8 mm (P </= 0.05). Disease-related mortality was not observed.

CONCLUSIONS

PTMC is prevalent in the population. Among patients with PTMC, tumor size more than 8 mm is associated with more aggressive disease.

Thyroid cancer review 2: management of differentiated thyroid cancers

This is the second review article on thyroid cancer dealing with the common differentiated types that comprise 90% of thyroid cancers. Despite clinical management guidelines offered by a number of organisations including the British Association of Otolaryngologists and Head and Neck Surgeon, The British Thyroid Association, The American Association Of Endocrinologists, The American Thyroid Association and the National Cancer Centre Network, debate regarding the management of differentiated thyroid cancer continues. This is because of the absence of good quality research evidence as a consequence of the natural history of this disease.

Unexpected Findings during Thyroid Surgery in a Regional Community Hospital: A 5-Year Experience of 738 Consecutive Cases

Unexpected findings during thyroid surgery in a nonuniversity setting have rarely been reported in large series. Our goal was to describe the unexpected findings during thyroid surgery in a busy regional community hospital. All thyroid operations conducted by the teaching staff at Greenville Memorial Hospital, a 735-bed nonuniversity regional hospital, from December 1998 through December 2003 were reviewed. Pre- and post-operative diagnoses, surgical procedure, and specimen histopathology were examined. Unexpected findings were defined as either thyroid pathology not anticipated based on preoperative diagnosis or as unsuspected nonthyroidal disease found during cervicotomy. During the 5-year study period, 738 patients presented with thyroid disease requiring surgery. Incidental thyroid cancer was discovered in 28 cases (3.8%), the predominance being papillary microcarcinoma. Synchronous benign thyroid disease, separate from the indication from surgery, was observed in 56 patients (7.6%). Forty patients had unexpected nodular goiter and 16 had lymphocytic thyroiditis. Primary hyperparathyroidism was observed in 33 patients (4.5%). Both solitary adenomas (22 cases) and multigland parathyroid disease (11 cases) were seen. Unexpected nonendocrine findings were less common, including solitary cases of large cell carcinoma, metastatic endometrial carcinoma, and tracheal duplication (bronchogenic cyst). In conclusion, unexpected findings during thyroid surgery at a busy community hospital are fairly common. Indeed, an unanticipated finding is encountered in one out of seven operations on the thyroid gland. Although most are of unclear clinical significance, there is a surprisingly high incidence of hyperparathyroidism. This underscores the need for preoperative screening, as the “thyroid patient” may also be the “parathyroid patient.”

Papillary thyroid microcarcinoma: A surgical perspective

Papillary thyroid microcarcinoma (PTMC) is defined as a papillary thyroid cancer measuring less than 10mm in its greatest diameter. It is the most common form of thyroid cancer, detected in up to 36% in autopsy studies. The wide availability and use of neck ultrasonography in the evaluation of carotid arteries and of the thyroid resulted in an increased detection of PTMC. PTMC is often multifocal. The diagnosis is usually based on a combination of clinical examination, laboratory investigations, and specialized radiological techniques (mainly neck ultrasonography combined with fine-needle aspiration cytology). A common scenario is the diagnosis of PTMC as an incidental finding following thyroidectomy for a presumably benign thyroid disease. Despite some controversy, most authors agree that PTMC should be treated by total or near-total thyroidectomy, provided it can be performed safely. Because of its many and major advantages, in our clinical practice, total or near-total thyroidectomy is the procedure of choice for the management of PTMC. Given the high incidence of PTMC as an incidental finding and the frequent multi-focality, we also favor total or near-total thyroidectomy for the surgical management of nodular thyroid disease (multinodular goiter or dominant presumably benign thyroid nodule/s). Despite some controversy, we perform central neck lymph node dissection electively, in the presence of cervical lymphadenopathy. Radioiodine ablation therapy may be used as an adjuvant therapy. Prognostic factors (such as tumor multicentricity, positive lymph nodes, capsular or vascular invasion) or scoring systems (such as the AMES) can be used to select patients for radioiodine adjuvant therapy. Suppression therapy is needed after surgical management. Despite the potential for neck lymph node and even distant metastases, the biological behavior of PTMC is in general benign and the prognosis is very good.

Expression profile of malignant and non-malignant diseases of the thyroid gland reveals altered expression of a common set of genes in goiter and papillary carcinomas

Using cDNA microarrays with 3800 cDNA fragments, we determined the expression profile of normal thyroid tissue, goiter, adenoma and papillary carcinoma (10 samples from each class). After background correction and statistical analysis, we identified a set of 160 genes as being differentially expressed in all pair-wise comparisons. Here we demonstrate that, at least on the basis of these differentially expressed genes, a positive correlation between goiter and papillary carcinomas could be observed. We identified a common set of genes whose expression is diminished in both goiter and papillary carcinomas as compared to normal thyroid tissue. Moreover, no genes with inverse correlation in samples from goiter and papillary carcinomas could be detected. Using Real-Time PCR and/or tissue microarrays, we confirmed the altered expression of some of the identified genes. Of notice, we demonstrate that the reduced mRNA levels of p27(kip1) observed in papillary carcinomas as compared to either goiter or normal thyroid tissues (P<0.001) is accompanied by an altered protein distribution within the cell. In papillary carcinomas, P27(KIP1) is preferentially cytoplasmic as opposed to goiter or normal thyroid tissue, where P27(KIP1) is preferentially located in the nucleus. The exploitation of the data presented here could contribute to the understanding of the molecular events related to thyroid diseases and gives support to the notion that common molecular events might be related to the frequent observation of areas of papillary carcinomas in the gland of patients with goiter.

Thyroid carcinomas involving follicular and parafollicular C cells: seventeen cases with characterization of RET oncogenic activation

Recent studies have focused on the occurrence of concomitant medullary-papillary thyroid carcinomas (MTC-PTC). The aims of this report were to compare the frequency of occult PTC in a population with MTC versus a control population that had undergone thyroidectomies and to check whether differences could be related to particular phenotype or genotype. To achieve these goals, we determined the frequency of occult PTC among patients operated for MTC (n = 82) or undergoing total thyroidectomy mainly for goiter and/or nodules (n = 7313) between 1994-2001. We then examined the clinical, histologic, and genetic characteristics (using a bio-chemical family inquiry and screening for RET germline mutations) of patients with associated PTC-MTC. Results show a significantly higher frequency of occult PTC in MTC (14.7%) than in total thyroidectomy (6.8%; p < 0.01). Seventeen cases of MTC or bilateral C-cell hyperplasia (CCH) and separate occult PTC were identified from 16 different families. Although common RET mutations providing evidence of familial forms of MTC were identified in only 3 of 16 families, clinical and histologic features usually seen in inherited forms of MTC such as young age of occurrence, bilateral CCH or associated case in family were found in 11 of the remaining 14 patients. In conclusion, results suggest that the association of MTC-PTC is not only a coincidence. Surprisingly, 11 of 17 MTC-PTC patients exhibited clinical, histologic, and/or family features usually encountered in familial forms despite the fact that no RET defect were present. This suggests the possible involvement of another gene or uncommon abnormality of RET gene.

Natural history, diagnosis, treatment and outcome of papillary thyroid microcarcinoma (PTMC): a mono-institutional 12-year experience

The clinical and histopathological records of 149 consecutive patients with papillary thyroid microcarcinoma (PTMC), homogeneously studied and operated on by the same surgeon in the period 1990 to 2001, were reviewed. After a mean 6.5-year follow-up, three cases of loco-regional recurrence (2%) were observed. These three patients had all undergone partial thyroidectomy only and tumour relapse occurred in the residual thyroid tissue. No recurrence was observed in patients treated by total thyroidectomy and I. At variance with other reported series, no lymph node recurrence was observed in our series, in particular in the group of 23 patients with evidence of nodal metastases at initial diagnosis (three of whom were revealed by I scan after surgery). Therefore, a preventive effect of I treatment in our patient population can be hypothesized. However, prolonged follow-up will be necessary to clarify this. Due to the inability of current imaging modalities to select pre-operatively PTMC patients at risk for recurrence (presence of thyroid capsular invasion, multifocality and microscopic lymph node metastases), it appears reasonable to offer the patient total thyroidectomy when a pre-operative diagnosis of PTMC is reached. Moreover, the policy of our thyroid cancer centre is that, in these patients, post-surgical I scan should be obtained in order to detect unknown metastatic deposits, and I treatment should also be considered in patients with poor clinical and histopathological prognostic factors. In contrast, in patients operated on for benign thyroid disease and with delayed diagnosis of PTMC at definitive histopathological examination, re-operation might be avoided in the presence of unifocal disease without thyroid capsular invasion and with ultrasound-'normal' residual thyroid tissue. Close clinical and ultrasound follow-up is recommended, especially in patients who have undergone conservative surgery only.

Nonpalpable thyroid carcinoma: clinical controversies on preoperative selection

This article emphasizes some controversies concerning the preoperative selection of nonpalpable thyroid tumors. The prevalence of occult thyroid carcinoma in surgical series (1.8-10%) is not higher than in autopsy thyroid series (2.7-24%). The prevalence of occult thyroid carcinoma in thyroid glands examined in the same institution by ultrasound, for a clinical thyroid abnormality or for investigation of other neck structures without clinically evident or suspected thyroid disease, varies from 3% to 8% and is very similar independent of the fact that a thyroid abnormality is or is not the indication for ultrasonography. These data suggest that the presence of a thyroid disease is not a risk factor for harboring an occult thyroid carcinoma (except for C-cell hyperplasia in the rare case of MEN 2 syndromes). As it is not cost effective to examine all the nonpalpable lesions with fine-needle aspiration (FNA) guided by ultrasounds, it is necessary to define to which extent ultrasound is useful in selecting those lesions to be examined cytologically by FNA. The use of ultrasound to select these lesions is very controversial. Ultrasound-guided cytologic diagnosis of nonpalpable nodules is not as accurate as in the case of palpable nodules. Sampling of material adequate for cytologic analysis depends on the lesion size; it is 64% for a 0.7-cm lesion and it increases to 86.7% for a mean size of 1.1 cm. For the diagnosis of occult thyroid carcinomas (< or =1 cm), sensitivity is 35.8% and false-negative results are 49.3%. Nonpalpable nodules with a size of 1.5 cm represent an absolute indication to perform an ultrasound-guided FNA because this is the size limit for dividing thyroid nodules in probably innocuous or potentially dangerous categories and because the cytologic diagnosis of nodules of this size is sufficiently reliable. For the smaller incidentally discovered thyroid nodules following ultrasound, physicians should discuss with the patient whether and when to perform an ultrasound-guided FNA considering the patient's data (risk factors, age, health state, etc.), the natural history of a small thyroid carcinoma, as well as the accuracy of ultrasound and ultrasound-guided FNA in the specific institution.

Differential expression of IGFBP-5 and two human ESTs in thyroid glands with goiter, adenoma and papillary or follicular carcinomas

Here, we describe the identification of three human genes with altered expression in thyroid diseases. One of them corresponds to insulin-like growth factor binding protein 5 (IGFBP5), which has already been described as over expressed in other cancers and, for the first time, is identified as overexpressed in thyroid tumors. The other genes, named 44 and 199, are ESTs with yet unknown function and were mapped on human chromosomes seven and four, respectively. We determined by RT-PCR the expression level of these genes in ten samples of disease-free thyroid, ten of goiter, nine of papillary carcinoma, ten of adenoma and seven of follicular carcinoma and the significance of observed differences was statistically determined. IGFBP-5 and gene 44 were significantly overexpressed in papillary carcinoma when compared to normal and goiter. Genes 44 and 199 were differentially expressed in follicular carcinoma and adenoma when compared to normal thyroid tissue.

Controversies in papillary microcarcinoma of the thyroid

Papillary thyroid carcinomas that are smaller than 1 cm are classified as papillary microcarcinomas (PMC). These lesions are frequently detected as incidental findings on autopsy or in surgical specimens. They are often multifocal. The relationship between PMC and clinical papillary thyroid carcinoma (PTC) is not clear. In patients with clinical thyroid cancer, PMC may represent intrathyroidal metastases; they may be the earliest form of future large lesions. These uncertainties raise questions about appropriate clinical management of patients with these lesions. Review of the literature substantiates the argument that clinically evident PTC may be distinctly different from solitary or multifocal PMC in terms of etiology and biologic behavior, supporting a conservative approach to management.

Pharmacotherapy for thyroid nodules. A systematic review and meta-analysis

The review highlights the uncertainty in the management of nodular thyroid disease. Thyroxine suppressive treatment is given in the hope that nodules might decrease in size, sometimes assuming that dependency on TSH is different in benign and malignant nodular disease. Follow-up of benign nodules over 10 years suggested that most remain the same, shrink, or disappear [14]. TSH suppression may lead to hyperthyroidism, reduced bone density [37.39], and atrial fibrilation; however, apart from reduction of nodule size or arrest in nodule growth, thyroxine therapy may benefit patients by reducing perinodular volume. Consequently, both pressure symptoms and cosmetic complaints could improve. Unfortunately, no information concerning symptoms or well-being is available from published randomized trials. In conclusion, more high quality studies of sufficient duration with adequate power estimation are needed. Uncertainty about predictors of response or the impact on outcomes that are important to patients leaves considerable doubt about the wisdom of applying suppressive therapy. Future studies shoudl include patient-important outcomes including thyroid cancer incidence, health-related quality of life and costs.

Fine-needle aspiration biopsy of the thyroid: comparison between thyroid palpation and ultrasonography

OBJECTIVE

To describe our experience with fine-needle aspiration biopsy (FNAB) of the thyroid and compare our results with direct palpation versus ultrasound scanning (USS) in an area of endemic goiter in Italy.

METHODS

We considered all patients submitted to ultrasound-guided FNAB of thyroid nodules during a 10-month period at our outpatient clinic and analyzed the following: (1) clinical data (number of nodules and identification of the nodule for FNAB); (2) USS data (number of nodules and identification of the nodule for FNAB on the basis of hypoechoic pattern + blurred perinodal halo + microcalcifications or intranodal color Doppler signal indicative of blood flow); (3) cytologic specimens, categorized as suspicious, malignant, negative, or nondiagnostic; and (4) histologic final report of the cytologically positive nodules.

RESULTS

The study group consisted of 348 female and 72 male patients who underwent FNAB of the thyroid at our institution. Among the 140 patients with no palpable thyroid nodules, USS showed that 106 had a single nodule and 34 had multinodular goiters. Among the 182 patients with a single palpable thyroid nodule, USS revealed that 138 had a single nodule, 42 had a multinodular goiter, and 2 had lobe enlargement without detectable nodules. All 98 patients with multinodular palpable goiter had a similar pattern on USS. Of the 420 cytologic specimens, 46(11.0%) were positive for thyroid cancer, 313 (74.5%)were negative, and 61 (14.5%) were nondiagnostic. Histologic malignant growth was confirmed in 27 cytologically positive nodules. Of these histologically malignant nodules, 12 (45%) were nonpalpable, 9 (33%) were single palpable nodules, and 6 (22%) were from a nodule with a suspicious ultrasound pattern within a multinodular goiter.

CONCLUSION

Manually guided FNAB is not feasible in nonpalpable nodules and not accurate in a multinodular goiter. Both situations are clinical challenges, and USS should be performed for accurate FNAB under these circumstances. Because 52% of histologically malignant nodules in our study were found only with the aid of ultrasound-guided FNAB, this procedure should be used where multinodular goiter is endemic. Our overall rate of nondiagnostic specimens was comparable to that reported in the literature.

Thyroid nodules: pathogenesis, diagnosis and treatment

Thyroid nodules are very frequently found and their prevalence steadily increases with age. The discovery of such lesions by high-resolution radiological imaging procedures that have been performed for other indications raises the problem of how incidentally discovered thyroid nodules should be investigated in a cost-effective manner to identify the rare patient with a clinically significant malignancy. In this review the clinical criteria that prompt the evaluation of thyroid nodules are discussed, as is the currently recommended diagnostic approach, which principally relies on fine needle aspiration biopsy. The clinical implications of the different cytological diagnoses are discussed, with a special emphasis on the management of indeterminate, microfollicular lesions. Finally, the evidence for and against suppressive thyroid hormone therapy for benign thyroid nodules and multinodular goitres is discussed, with particular consideration of high-risk patients with prior external radiation therapy to the neck region.

Multinodular goitre: 'much more to it than simply iodine deficiency'

For over a century, multinodular goitre (MNG) has been looked upon as the simple consequence of iodine deficiency. This view is now no longer tenable. Indeed, many characteristics of MNG do not fit with the iodine deficiency concept. For example, nodular goitre is a frequent disease even in those countries where the population is never exposed to iodine shortage. Moreover, neither multinodularity, nor the proverbial heterogeneity of growth and function or the autonomous, thyroid stimulating hormone (TSH)-independent growth of many goitres are compatible with the iodine deficiency concept, let alone subclinical or overt thyrotoxicosis which often complicates the course of a MNG. Recent investigations have led to the conclusion that MNGs are true benign neoplasias that are due to the high intrinsic growth potential of a variable, genetically predetermined fraction of all thyrocytes. Gross and heritable metabolic and functional differences between the individual thyrocytes, from which new follicles are generated during goitrogenesis, are the cause of the often spectacular functional and structural heterogeneity of MNG. Superimposed iodine deficiency changes the epidemiology, but not the basic mechanisms of goitrogenesis. These new pathogenetic concepts have a profound impact on the clinical management of MNG.

Thyroid incidentalomas. Prevalence, diagnosis, significance, and management

Thyroid incidentalomas are common, always impalpable, often less than 1.5 cm in size, and frequently benign. The authors recommend that low-risk patients with incidentalomas be followed up with clinical palpation in 6 to 12 months and not be subjected to routine testing with US-FNA. In the authors' strategy, fine-needle aspiration is reserved for an impalpable nodule and is performed under ultrasonographic guidance in the high-risk group of patients in whom either the imaging features or the clinical history is worrisome for malignancy. It does not seem necessary, practical, or cost-effective to perform biopsy or to excise surgically all impalpable nodules. Because of the high prevalence of thyroid incidentalomas, most of which are benign, a nonsurgical approach is logical.

Papillary microcarcinoma of the thyroid gland in renal transplant patients

Among organ transplant recipients there is a world wide increase in the number of de novo tumors as well as a decrease in the time of the first appearance after the transplantation. Between 1973 and the 31st of August 1999 1709 cadaver renal allograft transplantations were performed in our Department. Four thyroid cancers were detected among the renal transplanted patients. Two of them proved to be papillary microcarcinomas. Although the elevated risk of thyroid cancers is well established in the literature papillary microcarcinomas have never been reported before in an immunosuppressed patient. Authors highlight that the thyroid gland should always be carefully checked in organ transplant recipients, since better survival might be achieved even in the immunosuppressed population. Metastatic tumor is relatively benign which is in correlation with the literature, but there has been little experience in organ transplanted patients so far.

Extracapsular invasion of lymph node metastasis. A good indicator of disease recurrence and poor prognosis in patients with thyroid microcarcinoma

BACKGROUND

The majority of patients with thyroid microcarcinoma have a favorable prognosis. However, some patients may die from this tumor. Although the incidence of microcarcinoma is high, to the authors' knowledge no histologic risk factors have been identified. The objective of this study was to establish risk factors for patients with thyroid microcarcinoma.

METHODS

The histologic findings for 1743 surgically excised thyroid microcarcinomas (</=10 mm in greatest dimension) and simultaneously obtained lymph nodes from 324 microcancer patients were reexamined to determine risk factors. Follow-up for the patients was 11.2 +/- 6.3 years (mean +/- standard deviation). These thyroid carcinomas were classified according to the World Health Organization Histological Classification system, and lymph node involvement was classified into two groups: those patients with extracapsular invasion of the lymph node metastasis (ECI) (62 patients) and those patients without (1681 patients). A Fisher exact test, an F test, univariate and multivariate proportional hazards regression analyses, and a Kendall correlation measurement were performed.

RESULTS

No undifferentiated tumors were found among the microcarcinomas. During the follow-up period, 1643 of 1743 patients were alive without recurrence, 25 were alive with recurrence, 71 had died of thyroid-unrelated diseases including 2 patients with recurrence, and 4 had died of recurrent thyroid carcinoma. In total, recurrence was noted in 31 patients. Multivariate proportional hazards regression analysis revealed that the absence of Graves disease (risk ratio = 5) and the presence of ECI (risk ratio = 7) were significant risk factors for disease recurrence. Univariate analysis revealed that patient age and the presence of ECI were significant risk factors for thyroid carcinoma-related deaths.

CONCLUSIONS

The presence of ECI of lymph node metastasis in patients with thyroid microcarcinoma was found to be a significant indicator of disease recurrence and a poorer prognosis.

Prostate cancer screening: promise and peril--a review

This review summarizes the current status of and recommendations for prostate cancer screening with prostate-specific antigen in light of recent reductions in prostate cancer incidence and mortality. It describes how the uncertain effectiveness of aggressive treatment for prostate cancer and a reservoir of unsuspected indolent cancers make prostate cancer fit poorly into conventional screening models. The large proportion of men with unsuspected prostate cancers that may not cause morbidity or mortality and are unlikely to benefit from aggressive treatment decrease the effectiveness of a screening program. In addition, indolent, unsuspected prostate cancers in the screening population accentuate the detrimental effects of length bias on studies evaluating the effectiveness of prostate cancer screening. Screening tests for prostate cancer will continue to improve, but chemoprevention or nutritional prevention with vitamins and micronutrients such as tocopherols or selenium may prove to be effective methods of reducing prostate cancer incidence and should be aggressively investigated.

[Late effects of ionizing radiations on the thyroid gland]

The thyroid is the purest endocrine gland in the body and is likely to produce clinically significant abnormalities after external radiotherapy. Functional clinical modifications after direct irradiation exceeding 30 Gy are essentially related to hypothyroidism which may be clinically overt or subclinical with normal serum free thyroxine levels and high thyrotropin concentrations; the risk of hyperthyroidism, silent thyroiditis and Hashimoto's disease is also increased. Secondary hypothyroidism related to irradiation of the hypothalamus and the pituitary gland may arise with doses over 40-50 Gy following treatment for brain and nasopharyngeal tumors--Morphological glandular modifications induced by radiotherapy are responsible for the appearance of benign adenomas, more rarely cystic degenerations and specially well differentiated papillary or follicular carcinomas among children and adults. After irradiation during childhood for benign or malignant tumors, thyroid cancers are more frequent, higher for younger children, and the relative excess risk is increased from 15.6-to 53-fold; tumors can belatedly occur, more than 35 years after initial therapy. Thereby, in order to limit excess morbidity, it is evident that long term supervision with careful clinical and biological evaluations is necessary for patients who previously received neck, upper mediastinum and pituitary radiation therapy.

Imaging of the thyroid gland

The thyroid gland is critical in regulating metabolic functions including cardiac rate and output, lipid catabolism, skeletal growth, and oxygen and heat production. Thus, patients with hormonally active thyroid abnormalities present with wide-ranging symptoms, requiring an understanding of the gland's hormonal functions. Radiological imaging assesses the pathophysiological affects of abnormal thyroid function as well as important morphological features. Nuclear scintigraphy provides functional information about the gland, whereas cross-sectional imaging-including ultrasound, CT, and MR-provide adjunctive anatomic information. These modalities also provide information about related structures in the neck. The embryology, anatomy, and physiology of the thyroid are discussed; congenital, autoimmune, inflammatory, metabolic, and neoplastic diseases are reviewed; and the diagnostic utility of radiological imaging is addressed.

Papillary microcarcinoma of the thyroid gland

Papillary microcarcinomas are a specific subgroup of papillary thyroid cancer. They have the same histological features as papillary thyroid cancer but are 1.0 cm or less in diameter. These tumours are a common incidental finding at autopsy and in thyroid glands excised for other pathology. This tumour can metastasize to regional lymph nodes but its ability to cause significant morbidity and mortality has been questioned. As papillary microcarcinomas can represent up to 30 per cent of all papillary cancers seen in a thyroid surgeon's practice, they are an important group. The aim of this review article is to outline the natural history of papillary microcarcinoma and to offer therapeutic management strategies.

Highly aggressive behaviour of occult papillary thyroid carcinoma

Occult papillary thyroid carcinoma is generally associated with an excellent prognosis. Distant metastasis of this tumour is extremely rare. A case of occult papillary thyroid carcinoma with metastases to the lungs, cervical lymph nodes, skeleton, and the brain is reported. The tumour expressed itself in extremely aggressive clinical behaviour and responded only partially to aggressive therapy. The controversial methods of treatment for occult papillary thyroid carcinoma are also discussed.

Advances in the management of patients with thyroid disease

Discoveries related to thyroid immunology, especially concerning the thyroid-stimulating hormone (TSH) receptor, may facilitate new immunologic approaches to the therapy of Graves' disease and the thyroiditis syndromes. Advances in genetics are being applied to the thyroid hormone resistance syndromes and papillary and medullary carcinomas. The development of ever more sensitive TSH assays has led to the detection of subclinical thyroid disease, which has special implications for the sick and elderly patients. Sensitive TSH assays also allow more precise titration of levothyroxine (T4) dosages, especially for patients with a past history of thyroid cancer. Evidence continues to accumulate suggesting that postmenopausal women on T4 doses that suppress the TSH level below 0.1 ulU/mL have lower bone mineral density than matched patients with healthy TSH levels. Also, pregnant hypothyroid women need higher T4 doses to normalize the TSH levels. In the evaluation of thyroid nodules, fine-needle aspiration biopsy is the single most definitive modality in selecting the patients for surgery. Scintigraphy provides a complimentary role, especially in defining autonomously functioning thyroid adenomas (AFTA), because these should not be treated with T4 suppression. Ultrasound-guided needle biopsy is occasionally helpful with nodules that are difficult to palpate. Concern for possible tracheal compression after treatment of toxic multinodular goiter with large doses of radioactive iodine (I-131) in the range of 50 to 150 mCi (1.85 to 5.5 GBq) does not seem warranted. Work, primarily out of Italy, suggests AFTA can be ablated with repeat ethanol injections. Residual tissues after thyroidectomy for differentiated carcinoma can be "stunned" by tracer doses of 131I greater than 3.0 mCi (111 MBq), which diminishes the uptake and effectiveness of a subsequent therapy dose. Positron emission tomograph, imaging with thallium-201, and Technetium 99m Sestamibi can identify a small number of patients shown to have metastases from differentiated thyroid carcinoma by increasing thyroglobulin levels in the absence of 131I uptake. Several groups have recently advocated treating such patients empirically with 131I.