Latent thyroid carcinoma in Iceland at autopsy

Guidelines from the Brazilian society of surgical oncology regarding indications and technical aspects of neck dissection in papillary, follicular, and medullary thyroid cancers

Objective

The purpose of these guidelines is to provide specific recommendations for the surgical treatment of neck metastases in patients with papillary, follicular, and medullary thyroid carcinomas.

Materials and methods

Recommendations were developed based on research of scientific articles (preferentially meta-analyses) and guidelines issued by international medical specialty societies. The American College of Physicians' Guideline Grading System was used to determine the levels of evidence and grades of recommendations. The following questions were answered: A) Is elective neck dissection indicated in the treatment of papillary, follicular, and medullary thyroid carcinoma? B) When should central, lateral, and modified radical neck dissection be performed? C) Could molecular tests guide the extent of the neck dissection?

Results and conclusion

Recommendation 1: Elective central neck dissection is not indicated in patients with cN0 well-differentiated thyroid carcinoma or in those with noninvasive T1 and T2 tumors but may be considered in T3-T4 tumors or in the presence of metastases in the lateral neck compartments. Recommendation 2: Elective central neck dissection is recommended in medullary thyroid carcinoma. Recommendation 3: Selective neck dissection of levels II-V should be indicated to treat neck metastases in papillary thyroid cancer, an approach that decreases the risk of recurrence and mortality. Recommendation 4: Compartmental neck dissection is indicated in the treatment of lymph node recurrence after elective or therapeutic neck dissection; "berry node picking" is not recommended. Recommendation 5: There are currently no recommendations regarding the use of molecular tests in guiding the extent of neck dissection in thyroid cancer.

Prevalence of Subclinical Papillary Thyroid Cancer by Age: Meta-analysis of Autopsy Studies

CONTEXT

It is not known how underlying subclinical papillary thyroid cancer (PTC) differs by age. This meta-analysis of autopsy studies investigates how subclinical PTC prevalence changes over the lifetime.

METHODS

We searched PubMed, Embase, and Web of Science databases from inception to May 2021 for studies that reported the prevalence of PTC found at autopsy. Two investigators extracted the number of subclinical PTCs detected in selected age groups and extent of examination. A quality assessment tool was used to assess bias. Logistic regression models with random intercepts were used to pool the age-specific subclinical PTC prevalence estimates.

RESULTS

Of 1773 studies screened, 16 studies with age-specific data met the inclusion criteria (n = 6286 autopsies). The pooled subclinical PTC prevalence was 12.9% (95% CI 7.8-16.8) in whole gland and 4.6% (2.5- 6.6) in partial gland examination. Age-specific prevalence estimates were ≤40 years, 11.5% (6.8-16.1); 41-60 years, 12.1% (7.6-16.5); 61-80 years, 12.7% (8-17.5); and 81+ years, 13.4% (7.9-18.9). Sex did not affect age-specific prevalence and there was no difference in prevalence between men and women in any age group. In the regression model, the OR of prevalence increasing by age group was 1.06 (0.92-1.2, P = .37).

CONCLUSION

This meta-analysis shows the prevalence of subclinical PTC is stable across the lifespan. There is not a higher subclinical PTC prevalence in middle age, in contrast to higher observed incidence rates in this age group. These findings offer unique insights into the prevalence of subclinical PTC and its relationship to age.

Adverse Histological Features of Differentiated Thyroid Cancer Are Commonly Found in Autopsy Studies: Implications for Treatment Guidelines

Background: While the popularity of lobectomy for differentiated thyroid cancer (DTC) has increased since the 2015 ATA (American Thyroid Association) guidelines, recent studies reported that adverse histological features (minimal extrathyroidal extension [mETE], multifocality, vascular invasion, and lymph node [LN] metastases) may be found in 30-60% of lobectomy specimens, questioning the validity of this approach. Aim: To assess the prevalence adverse histological features in occult DTC detected in autopsy studies. Methods: Meta-analysis of autopsy studies of the thyroid in subjects without known history of thyroid cancer. Results: Twenty-nine studies including 8750 subjects fulfilled the inclusion criteria, with incidentally discovered DTC in 740 autopsies (8.5%). Age was reported in 17 studies, with a median age of 61 years (range 41-68 years). Multifocality was reported in 27 studies with a calculated event rate of 28.2% ([CI 23.1-33.8], I² = 46.3%), with bilateral involvement in 18% [CI 12.6-25.1]. mETE was reported in 5 studies, with an event rate of 24.5% ([CI 9.3-50.7], I² = 88.5%), and the presence of LN metastases were reported in 13 studies with an event rate of 11% ([CI 6.1-19.1], I² = 69.5%). Vascular invasion was reported in seven studies with an event rate of 16% ([CI 4-47], I² = 86.8%). Of 25 studies with whole body autopsies (722 subjects), 3 cases of distant metastases were reported, of which 2 had fatal metastatic disease (where thyroid origin was not diagnosed before death), and 1 had occult disease. Conclusions: Adverse histological features including mETE, LN metastases, multifocality, and vascular invasion are common in occult DTC. When minimal in size, these adverse histological features do not seem to be markers of aggressive disease and may not be an indication for completion thyroidectomy or radioiodine therapy.

Rethinking Low-Risk Papillary Thyroid Cancers < 1cm (Papillary Microcarcinomas): An Evidence Review for Recalibrating Diagnostic Thresholds and/or Alternative Labels

Background: Recalibrating diagnostic thresholds or using alternative labels may mitigate overdiagnosis and overtreatment of papillary microcarcinoma (mPTC). We aimed at identifying and collating relevant epidemiological evidence on mPTC, to assess the case for recalibration and/or new labels. Methods: We searched EMBASE and PubMed databases from inception to December 2020 for natural history, autopsy, diagnostic drift, and diagnostic reproducibility studies. Where a relevant systematic review was pre-identified, only new articles were additionally included. Non-English articles were excluded. One author screened titles and abstracts. Two authors screened full text articles, performed quality assessments, and extracted data. We undertook narrative synthesis of included evidence (pooled estimates from systematic reviews and single estimates from primary studies). Results: One systematic review of patients undergoing active surveillance found that after 5 years of follow-up, 5.3% (95% confidence interval [CI 4.4-6.4%]) of the mPTC lesions had increased in size by ≥3 mm, and 1.6% [CI 1.1-2.4%] of patients had lymph node metastases. Among 7 new primary studies (including 3 updates on 2 studies included in the systematic review), 1-5% of patients undergoing active surveillance had lymph node metastases after a median follow-up of 1-10 years. One systematic review found that subclinical thyroid cancer incidentally discovered at autopsy is relatively common, with a pooled prevalence of 11.2% [CI 6.7-16.1%] among studies that examined the whole thyroid. Four diagnostic drift studies evaluated the new classification of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Three studies of cases previously diagnosed as papillary thyroid cancer found 1.3-2.3% were reclassified as NIFTP (reclassifications were from follicular variation of papillary thyroid cancer [FVPTC]). One study of 48 cases previously diagnosed as mPTC found that 23.5% were reclassified as NIFTP. Thirteen reproducibility studies of papillary thyroid lesions found substantial variation in the histopathological diagnosis of thyroid lesions, including FVPTC and NIFTP classifications (no study evaluated mPTC). Conclusions: This review supports consideration of recalibrating diagnostic thresholds and/or alternative labels for low-risk mPTC.

Evaluation of Gender Inequity in Thyroid Cancer Diagnosis: Differences by Sex in US Thyroid Cancer Incidence Compared With a Meta-analysis of Subclinical Thyroid Cancer Rates at Autopsy

IMPORTANCE

Thyroid cancer is more common in women than in men, but the associated causes of these differences are not fully understood.

OBJECTIVE

To compare sex-specific thyroid cancer rates in the US to the prevalence of subclinical thyroid cancer at autopsy.

DATA SOURCES

Data on thyroid cancer incidence and mortality by sex among US adults (≥18 years) were extracted from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program (SEER) data for 1975 to 2017. Embase, PubMed, and Web of Science databases were searched for studies on the prevalence of subclinical thyroid cancer at autopsy of men and women, from inception to May 31, 2021.

STUDY SELECTION

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was used to perform a systematic search for articles reporting the prevalence of subclinical thyroid cancer in autopsy results of both women and men. Of 101 studies identified, 8 studies containing 12 data sets met inclusion criteria; ie, they examined the whole thyroid gland, stated the number of thyroids examined, and reported results by sex. Excluded studies reported thyroid cancer in Japan after the atomic bombs or Chernobyl after the nuclear disaster; did not examine the whole thyroid gland or had incomplete information on thyroid examination methods; or did not report rates by sex.

DATA EXTRACTION AND SYNTHESIS

Thyroid cancer incidence and mortality data by sex, histologic type, and tumor size were extracted from SEER. The inverse variance heterogeneity model was used to meta-analyze the prevalence and the odds ratio of subclinical thyroid cancer by sex from 8 studies (12 data sets) on thyroid cancer prevalence in autopsy results.

MAIN OUTCOMES AND MEASURES

Incidence and mortality of thyroid cancer, by histologic type and tumor size; prevalence of thyroid cancer in autopsy results.

RESULTS

In 2017, 90% of thyroid cancers diagnosed were papillary thyroid cancer (PTC) and in 2013 to 2017, the women to men incidence ratio for small (≤2 cm) PTC was 4.39:1. The incidence ratio approached 1:1 as cancer type lethality increased. The ratio of thyroid cancer mortality by gender was 1.02:1 and remained stable from 1992 to 2017. Results of the meta-analysis showed that the pooled autopsy prevalence of subclinical PTC was 14% in women (95% CI, 8%-20%) and 11% in men (95% CI, 5%-18%). The pooled odds ratio of subclinical PTC in women compared with men was 1.07 (95% CI, 0.80-1.42).

CONCLUSIONS AND RELEVANCE

This cohort study and meta-analysis found that the belief that women get thyroid cancer more often than men is an oversimplification. The gender disparity is mostly confined to the detection of small subclinical PTCs, which are equally common in both sexes at autopsy but identified during life much more often in women than men. As the lethality of the cancer type increases, the ratio of detection by gender approaches 1:1. This phenomenon may be associated with gender differences in health care utilization and patterns of clinical thinking and can harm both women, who are subject to overdetection, and men, who may be at risk of underdetection.

Medullary thyroid carcinoma with diabetic ketoacidosis: an autopsy case report and literature review

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor of parafollicular C cells. The majority of MTCs occur sporadically, but about 30% of the cases are associated with multiple endocrine neoplasia type 2 (MEN2) syndrome or familial MTC. Generally, MTCs have no clinical manifestation, but infrequently the patients develop symptoms of hypercortisolism by secreting adrenocorticotropic hormone (ACTH) or corticotropin-releasing hormone (CRH). Although ectopic Cushing syndrome is only found in 0.7% of MTC patients, it can lead to fatal consequences if left untreated. Over 50 cases of MTC-related Cushing syndrome have been reported, and few autopsy cases exist in the literature. In those cases, the tumor cells are positive for calcitonin, but mostly display negative immunostaining for ACTH or CRH. The authors report an autopsy case of a 22-year-old woman who was found dead with no medical history whose cause of death was diabetic ketoacidosis associated with MTC, which showed poor calcitonin stainability.

Contribution of Weight and Volume of the Extirpated Thyroid Gland on Voice Alterations After Total Thyroidectomy in Patients With Papillary Carcinoma of the Thyroid

PURPOSE

Voice change after thyroid surgery is common despite preservation of laryngeal nerves. In this study, we sought to find if the change in voice after total thyroidectomy is related to the weight and volume of the removed thyroid gland.

METHODS

This is a prospective cohort study of 50 patients of papillary carcinoma of the thyroid treated with total thyroidectomy from December 2016 through May 2018. Both objective and subjective voice parameters were analyzed preoperatively and at 1 and 3 months following surgery.

RESULTS

A cohort of 29 patients, with a median age of 31 years (18-64 years), comprising 22 women were eligible for final analysis. Speaking fundamental frequency showed a mean change of 17.21 Hz (SD 34.49) while the mean intensity change was 5.54 dB (SD 18.21). The mean weight and volume of thyroid gland was 18.99 g (SD 8.93) and 15.67 ml (SD 8.70), respectively. On multivariate analysis, both weight and volume affected the range of frequency (P = 0.002 and 0.035, respectively) and range of intensity (P = 0.014 and 0.008, respectively).

CONCLUSION

Larger thyroid tumors are more likely to be associated with transient change in voice quality following their surgical removal despite physical preservation of external and recurrent laryngeal nerves, which may persist up to 3 months. This study affirms that perturbations in voice after thyroidectomy can still exist in spite of clinical demonstration of integrity of neuromuscular function.

Clinicopathological characteristics and recurrence risk of papillary thyroid microcarcinoma in the elderly

Background: The optimal management for elderly patients with papillary thyroid microcarcinoma (PTMC) is not well established. The aim of the present study is to describe the clinicopathological characteristics and identify predictors of recurrence in the elderly PTMC patients.

Methods: We conducted a retrospective study of PTMC patients who underwent thyroidectomy. The clinicopathological characteristics were compared between patients with age ≥65 years and <65 years. The independent predictors of recurrence were identified by multivariate Cox regression analysis.

Results: The patients in elderly group were more likely to exhibit bilaterality (P<0.050), extrathyroidal extension (P < 0.001), and central compartment lymph node metastasis (CLNM) (P<0.010), especially the ratio of CLNM >0.5 (P<0.010), than the patients with age <65 years. The elderly patients had poorer recurrence-free survival (RFS) than those with younger ages (P=0.002). Multivariate analysis indicated tumor size >5 mm (P=0.009) and CLNM ratio >0.5 (P=0.002) were independent risk factors for recurrence of the elderly patients with PTMC.

Conclusions: The elderly PTMC patients have more aggressive biological characteristics and higher recurrence rate. More aggressive treatment and rigorous follow-up could be considered for elderly patients with tumor diameter >5 mm and CLNM ratio >0.5.

Prevalence of Differentiated Thyroid Cancer in Autopsy Studies Over Six Decades: A Meta-Analysis

Purpose

Differentiated thyroid cancer (DTC) incidence has been reported to have increased three- to 15-fold in the past few decades. It is unclear whether this represents overdiagnosis or a true increase in incidence. Therefore, the current study aimed to estimate the prevalence of incidental DTC in published autopsy series and determine whether this prevalence has been increasing over time.

Materials and Methods

PubMed, Embase, and Web of Science were searched from inception to December 2015 for relevant studies. Two authors searched for all autopsy studies that had included patients with no known history of thyroid pathology and reported the prevalence of incidental DTC (iDTC). Two authors independently extracted the data, and discrepancies were resolved by another author. The pooled prevalence of iDTC was assessed using a fixed-effects meta-analysis model with robust error variance. The time effect was studied using an inverse-variance weighted logit-linear regression model with robust error variance and a time variable.

Results

Thirty-five studies, conducted between 1949 and 2007, met the inclusion criteria and contributed 42 data sets and 12,834 autopsies. The prevalence of iDTC among the partial and whole examination subgroups was 4.1% (95% CI, 3.0% to 5.4%) and 11.2% (95% CI, 6.7% to 16.1%), respectively. Once the intensiveness of thyroid examination was accounted for in the regression model, the prevalence odds ratio stabilized from 1970 onward, and no time effect was observed.

Conclusion

The current study confirms that iDTC is common, but the observed increasing incidence is not mirrored by prevalence within autopsy studies and, therefore, is unlikely to reflect a true population-level increase in tumorigenesis. This strongly suggests that the current increasing incidence of iDTC most likely reflects diagnostic detection increasing over time.

Incidences of Unfavorable Events in the Management of Low-Risk Papillary Microcarcinoma of the Thyroid by Active Surveillance Versus Immediate Surgery

BACKGROUND

The incidence of papillary microcarcinoma (PMC) of the thyroid is rapidly increasing globally, making the management of PMC an important clinical issue. Excellent oncological outcomes of active surveillance for low-risk PMC have been reported previously. Here, unfavorable events following active surveillance and surgical treatment for PMC were studied.

METHODS

From February 2005 to August 2013, 2153 patients were diagnosed with low-risk PMC. Of these, 1179 patients chose active surveillance and 974 patients chose immediate surgery. The oncological outcomes and the incidences of unfavorable events of these groups were analyzed.

RESULTS

In the active surveillance group, 94 patients underwent surgery for various reasons; tumor enlargement and the appearance of novel lymph node metastases were the reasons in 27 (2.3%) and six patients (0.5%), respectively. One of the patients with conversion to surgery had nodal recurrence, and five patients in the immediate surgery group had a recurrence in a cervical node or unresected thyroid lobe. All of these recurrences were successfully treated. None of the patients had distant metastases, and none died of the disease. The immediate surgery group had significantly higher incidences of transient vocal cord paralysis (VCP), transient hypoparathyroidism, and permanent hypoparathyroidism than the active-surveillance group did (4.1% vs. 0.6%, p < 0.0001; 16.7% vs. 2.8%, p < 0.0001; and 1.6% vs. 0.08%, p < 0.0001, respectively). Permanent VCP occurred only in two patients (0.2%) in the immediate surgery group. The proportion of patients on L-thyroxine for supplemental or thyrotropin (TSH)-suppressive purposes was significantly larger in the immediate surgery group than in the active surveillance group (66.1% vs. 20.7%, p < 0.0001). The immediate surgery group had significantly higher incidences of postsurgical hematoma and surgical scar in the neck compared with the active surveillance group (0.5% vs. 0%, p < 0.05; and 8.0% vs. 100%, p < 0.0001, respectively).

CONCLUSIONS

The oncological outcomes of the immediate surgery and active surveillance groups were similarly excellent, but the incidences of unfavorable events were definitely higher in the immediate surgery group. Thus, active surveillance is now recommended as the best choice for patients with low-risk PMC.

Iodine intake as a risk factor for thyroid cancer: a comprehensive review of animal and human studies

Thyroid cancer (TC) is the most common endocrine malignancy and in most countries, incidence rates are increasing. Although differences in population iodine intake are a determinant of benign thyroid disorders, the role of iodine intake in TC remains uncertain. We review the evidence linking iodine intake and TC from animal studies, ecological studies of iodine intake and differentiated and undifferentiated TC, iodine intake and mortality from TC and occult TC at autopsy, as well as the case–control and cohort studies of TC and intake of seafood and milk products. We perform a new meta-analysis of pooled measures of effect from case–control studies of total iodine intake and TC. Finally, we examine the post-Chernobyl studies linking iodine status and risk of TC after radiation exposure. The available evidence suggests iodine deficiency is a risk factor for TC, particularly for follicular TC and possibly, for anaplastic TC. This conclusion is based on: a) consistent data showing an increase in TC (mainly follicular) in iodine deficient animals; b) a plausible mechanism (chronic TSH stimulation induced by iodine deficiency); c) consistent data from before and after studies of iodine prophylaxis showing a decrease in follicular TC and anaplastic TC; d) the indirect association between changes in iodine intake and TC mortality in the decade from 2000 to 2010; e) the autopsy studies of occult TC showing higher microcarcinoma rates with lower iodine intakes; and f) the case control studies suggesting lower risk of TC with higher total iodine intakes.

Patient age is significantly related to the progression of papillary microcarcinoma of the thyroid under observation

BACKGROUND

We showed previously that subclinical low-risk papillary thyroid microcarcinoma (PTMC) could be observed without immediate surgery. Patient age is an important prognostic factor of clinical papillary thyroid carcinoma (PTC). In this study, we investigated how patient age influences the observation of low-risk PTMC.

METHODS

Between 1993 and 2011, 1235 patients with low-risk PTMC chose observation without immediate surgery. They were followed periodically with ultrasound examinations. These patients were enrolled in this study. We divided them into three subsets based on age at the beginning of observation: young (<40 years), middle-aged (40-59 years), and old patients (≥60 years). Observation periods ranged from 18 to 227 months (average 75 months).

RESULTS

We set three parameters for the evaluation of PTMC progression: (i) size enlargement, (ii) novel appearance of lymph-node metastasis, and (iii) progression to clinical disease (tumor size reaching 12 mm or larger, or novel appearance of nodal metastasis). The proportion of patients with PTMC progression was lowest in the old patients and highest in the young patients. On multivariate analysis, young age was an independent predictor of PTMC progression. However, none of the 1235 patients showed distant metastasis or died of PTC during observation. Although only 51 patients (4%) underwent thyrotropin (TSH) suppression based on physician preference, the PTMC of all patients enrolled in this TSH suppression study, except one, were clinically stable. To date, 191 patients underwent surgery for various reasons after observation. None showed recurrence except for one in the residual thyroid, and none died of PTC after surgery.

CONCLUSIONS

Old patients with subclinical low-risk PTMC may be the best candidates for observation. Although PTMC in young patients may be more progressive than in older patients, it might not be too late to perform surgery after subclinical PTMC has progressed to clinical disease, regardless of patient age.

Prognosis and growth activity depend on patient age in clinical and subclinical papillary thyroid carcinoma

In this review, we focused on the patient age as an indicator of tumor growth and prognostic significance in both clinical papillary thyroid carcinoma (PTC) and subclinical papillary microcarcinoma (PMC: PTC ≤ 1 cm). In clinical PTC, young age (< 30 years) and old age (≥ 60 years) significantly affected the disease-free survival of patients, and old age was a strong predictor of carcinoma death. In contrast, in subclinical PMC, growth activity significantly decreased with patient age, and young age (< 40 years) was an independent predictor of carcinoma growth, indicating that old patients with subclinical PMC are the best candidates for observation without immediate surgery. Taken together, our findings indicate that the role of patients' age as an indicator of tumor growth differs significantly between clinical PTC and subclinical PMC.

Increasing incidence of thyroid cancer: controversies explored

Thyroid cancer is the most common endocrine malignancy and its incidence has been increasing considerably in the past few decades. Many studies have been published providing evidence for this increase; however, why thyroid cancer incidence keeps rising is still debated and there are conflicting reports of factors leading to the increase in its incidence. In this article, Nature Reviews Endocrinology asks four experts their opinions on some of the controversies surrounding the changing trends in thyroid cancer incidence.

Papillary thyroid carcinoma patients assessed to be at low or intermediary risk after primary treatment are at greater risk of long term recurrence if they are thyroglobulin antibody positive or do not have distinctly low thyroglobulin at initial assessment

BACKGROUND

In papillary thyroid carcinoma (PTC), recurrences during long-term follow-up (R-LTFU) occur even in those who appear to have an excellent prognosis after initial thyroid surgery and usually, radioactive iodine (i.e., "primary treatment"). Initial studies that predict R-LTFU are not well defined. Values for serum thyroglobulin (Tg) measurements when serum thyrotropin (TSH) is >30 μU/mL, as a result of either recombinant TSH or L-thyroxine withdrawal, referred to here as stimulated Tg (STg), have been previously evaluated. The aim of the current study was to determine the parameters associated with R-LTFU in patients with PTC categorized as having low-risk disease 9 to 12 months after their primary treatment.

METHODS

This was a retrospective study of 469 patients with PTC with a mean follow-up 5.8±3.9 years. Study patients had to have no uptake in the first postablative diagnostic (131)iodine whole body scan (WBS) performed 9-12 months after primary treatment, a normal cervical ultrasonography (C-US), and STg of <2 ng/mL if their test for antithyroglobulin antibody (anti-Tg) was negative. The first two criteria were required for patients with a positive anti-Tg test, and their nominal serum Tg concentrations were not analyzed.

RESULTS

Twelve patients developed recurrences (2.6%) in cervical region. Greater tumor size, higher STg, and positive anti-Tg tests at initial evaluation were associated with greater R-LTFU. The recurrence rates were 1.5% (7/450) and 26% (5/19), respectively, in patients with negative and positive anti-Tg tests at initial evaluation. Recurrence-free survival was lower in the patients with initial lymph node metastases, positive anti-Tg tests, and STg of ≥0.3 ng/mL at the first postablative WBS (p=0.022, 0.001, 0.035, respectively, by log-rank test). Regression analysis in patients who were anti-Tg negative revealed that STg ≥0.3 ng/mL at this first WBS was the only parameter related to recurrence (p=0.031, odds ratio: 10.30, confidence interval: 1.23-83.3).

CONCLUSION

Patients with PTC traditionally categorized as low risk during their first 9 to 12 months after primary treatment have a greater risk of R-LTFU if their postablative STg is ≥0.3 ng/mL, or they have positive anti-Tg, even at this early stage. Periodic C-US is important in these patients and should probably be more frequent in patients with PTC who have positive anti-Tg tests or STg ≥0.3 ng/mL in the first year after diagnosis.

Screening for medullary thyroid carcinoma with serum calcitonin measurements in patients with thyroid nodules in the United States and Canada

BACKGROUND

Medullary thyroid carcinoma (MTC) is a rare thyroid malignancy with the potential for aggressive behavior. Measurement of serum calcitonin (Ct) in the thyroid nodule population is the most sensitive way to detect occult MTC. An important and controversial question is whether all patients with thyroid nodules should undergo Ct measurements to detect occult MTC.

SUMMARY

The prevalence of MTC detected by performing surgery on unselected individuals with thyroid nodules with elevated serum Ct is 0.4%. The central role of pentagastrin (PG) stimulation for triaging patients with minimally elevated serum Ct to prevent unnecessary surgery is reviewed. Data concerning a large reservoir of medullary thyroid microcarcinomas are discussed.

CONCLUSION

Given the unavailability of PG in the United States and Canada, the available data argue against routine Ct measurements in all individuals with thyroid nodules in these countries because of the potential for unnecessary surgery and the uncertain benefit in diagnosing medullary microcarcinoma.

Prognostic factors of papillary and follicular carcinomas in Japan based on data of kuma hospital

There are some important prognostic factors for papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC). In this paper, clinicopathological features significantly affecting patient prognosis are described based on our data as well as others. Distant metastasis at diagnosis is the most important prognostic factor for both PTC and FTC. Other than that, preoperative and intraoperative findings are important to evaluate the biological behavior of PTC. Extrathyroid extension, large lymph-node metastasis, and extranodal tumor extension that can be evaluated preoperatively or intraoperatively are significant prognostic factors for PTC patients. In contrast, pathological findings are important not only for diagnosis of FTC, but also for the evaluation of its biological character. Grade of invasiveness (minimally or widely invasive) and degree of differentiation (well differentiated or including a poorly differentiated component) greatly affect the prognosis of FTC patients.

Thyroid ultrasonography

BACKGROUND

The recent prevalence of ultrasonography (US) has facilitated the early detection and qualitative evaluation of thyroid nodules. Furthermore, novel technical developments are extending the application range of US for other thyroid diseases.

METHODS

The use of US to differentiate between thyroid carcinoma and benign nodule, between a metastatic lymph node and a reactive node, between thyroid lymphoma and chronic thyroiditis, and between destruction-induced thyrotoxicosis and Graves' disease is introduced.

RESULTS

Classification systems for thyroid nodule have shown high diagnostic accuracy for thyroid carcinomas except follicular carcinoma. US diagnosis of lymph node metastasis showed high specificity but low sensitivity. Patients who were suspected of thyroid lymphoma based on US findings should undergo incisional biopsy or thyroidectomy for diagnosis of the histologic type if fine-needle aspiration biopsy findings suggest lymphoma. Patients should be carefully followed even if they were diagnosed as negative based on cytologic findings. Measurement of thyroid blood flow is helpful for diagnosing destruction-induced thyrotoxicosis, such as painless thyroiditis, by distinguishing the lesion from Graves' disease.

CONCLUSIONS

Ultrasonography is useful for diagnosing various thyroid diseases, including thyroid carcinoma. The remaining issue to be resolved is the diagnosis of follicular carcinoma. Trials using novel techniques to differentiate these lesions are expected.

An observational trial for papillary thyroid microcarcinoma in Japanese patients

BACKGROUND

The recent development and spread of ultrasonography and ultrasonography-guided fine needle aspiration biopsy (FNAB) has facilitated the detection of small papillary microcarcinomas of the thyroid measuring 1 cm or less (PMC). The marked difference in prevalence between clinical thyroid carcinoma and PMC detected on mass screening prompted us to observe PMC unless the lesion shows unfavorable features, such as location adjacent to the trachea or on the dorsal surface of the thyroid possibly invading the recurrent laryngeal nerve, clinically apparent nodal metastasis, or high-grade malignancy on FNAB findings. In the present study we report comparison of the outcomes of 340 patients with PMC who underwent observation and the prognosis of 1,055 patients who underwent immediate surgery without observation.

METHODS

Between 1993 and 2004, 340 patients underwent observation and 1,055 underwent surgical treatment without observation. These 1,395 patients were enrolled in the present study. Observation periods ranged from 18 to 187 months (average 74 months).

RESULTS

The proportions of patients whose PMC showed enlargement by 3 mm or more were 6.4 and 15.9% on 5-year and 10-year follow-up, respectively. Novel nodal metastasis was detected in 1.4% at 5 years and 3.4% at 10 years. There were no factors related to patient background or clinical features linked to either tumor enlargement or the novel appearance of nodal metastasis. After observation 109 of the 340 patients underwent surgical treatment for various reasons, and none of those patients showed carcinoma recurrence. In patients who underwent immediate surgical treatment, clinically apparent lateral node metastasis (N1b) and male gender were recognized as independent prognostic factors of disease-free survival.

CONCLUSIONS

Papillary microcarcinomas that are not associated with unfavorable features can be candidates for observation regardless of patient background and clinical features. If there are subsequent signs of progression, such as tumor enlargement and novel nodal metastasis, it would not be too late to perform surgical treatment. Even though the primary tumor is small, careful surgical treatment including therapeutic modified neck dissection is necessary for N1b PMC patients.

Lateral lymph node metastasis in papillary thyroid carcinoma: results of therapeutic lymph node dissection

BACKGROUND

Cervical lymph node metastases are quite common in papillary thyroid cancer (PTC) and they usually spread in a contiguous fashion. However, "skip metastasis," defined as lateral lymph node metastasis without central lymph node metastasis, also occurs in patients with PTC. There is little information regarding skip metastasis in papillary thyroid microcarcinoma (PTMC). The goal of this study was to determine the prevalence and associated clinical and imaging features of skip metastasis in PTMC.

METHODS

We performed a retrospective study of 245 patients with PTMC who underwent either thyroidectomy and central lymph node dissection or thyroidectomy, central lymph node dissection, and lateral lymph node dissection if preoperative ultrasonography or computed tomography suggested lateral node metastasis. Clinicopathologic results were reviewed, and the patterns of cervical lymph node metastasis were analyzed.

RESULTS

Cervical lymph node metastases were present in 26.5% of cases. The frequency of lymph node metastases was 21.8% in the group that only had thyroidectomy and central lymph node dissection and 51.3% in the group that had thyroidectomy, central lymph node dissection, and lateral lymph node dissection. Younger age, larger tumor size, multiplicity, bilaterality, encapsulation, extrathyroid extension, and lymphatic invasion were associated with metastasis to nodes in the central or lateral compartment. Lateral lymph node dissection was performed in 15.9% of patients. Skip metastasis was observed in 7.7% of the cases in which combined central and lateral node dissection was performed. No features of the primary thyroid tumor could be associated with the development of skip metastasis.

CONCLUSIONS

Skip metastases occur in a minority of patients with PTMC. We recommend, therefore, that preoperative studies in patients suspected of having PTMC focus not only on nodes in the central compartment but also lateral cervical nodes since the information obtained would guide the extent of surgery.

Prognostic factors and therapeutic strategies for differentiated carcinomas of the thyroid

Differentiated thyroid carcinoma originates from thyroid follicular cells and is the most prominent malignancy of the endocrine organs. There are two histological types of differentiated carcinoma, namely, papillary and follicular carcinoma. According to reports from Western countries, papillary carcinoma comprises 85.3% of thyroid malignancies in whites, and 72.3% in blacks. In Japan, a previous study showed that the prevalence of papillary carcinoma was 78.4% based on material registered between 1977 and 1986, but according to recent findings reported in 2004 by Japanese Society of Thyroid Surgeons (JSTS), papillary carcinoma accounted for as much as 93% of all thyroid carcinomas. Papillary carcinoma frequently metastasizes to the regional lymph node and shows multicentricity in the thyroid gland. It usually shows a typical ultrasonographic appearance and can be rather easily diagnosed by fine needle aspiration biopsy (FNAB). Follicular carcinoma accounts for 10.9-20.5% of the patients in the United States. In Japan, the prevalence of follicular carcinoma was reported to be 17.2%, but it decreased to 5% in a report by JSTS in 2004. This carcinoma is only occasionally diagnosed preoperatively, because it is hard to discriminate follicular carcinoma from benign adenoma on imaging studies and cytologic findings. In contrast to papillary carcinoma, follicular carcinoma more often metastasizes to distant organs than regional lymph nodes. In Japan, the prevalence of papillary carcinoma increased and that of follicular carcinoma decreased between reports from 1977 to 1986 and that in 2004, which may be because follicular variant of papillary carcinoma was classified into follicular carcinoma in the previous results. Generally, these carcinomas show an indolent character, but when the lesion dedifferentiates and becomes undifferentiated carcinoma, it displays very rapid growth with an adverse prognosis and is regarded even as the most aggressive malignancy among human solid carcinomas. Furthermore, cases showing certain characteristics are likely to be constantly progressive and even become life-threatening. Such cases should be regarded as "high-risk" requiring careful and extensive surgical treatment and postoperative follow-up. Indeed, it is most important for physicians to correctly distinguish high-risk cases from those with an indolent character, although how to evaluate the biological characteristics of thyroid carcinoma and how to identify high-risk cases remains highly controversial. In this review, the methods of distinguishing high-risk cases and the appropriate therapeutic strategies for papillary and follicular carcinomas predominantly based on our experience are emphasized and our proposals for therapies including surgical treatment are demonstrated.

Appropriate treatment for asymptomatic papillary microcarcinoma of the thyroid

Since the 1990 s, asymptomatic papillary microcarcinoma (PMC), papillary carcinoma measuring <or= 1.0 cm, has frequently been detected using ultrasonographic screening and diagnosed by ultrasonography-guided fineneedle aspiration biopsy. Thyroid carcinoma was detected in 3.5% of otherwise healthy women aged >or= 30 years of age and most of these patients had lesions measuring <or= 1.5 cm in diameter, which is not discrepant with previous autopsy findings that latent PMC showed a high incidence. A recent observation trial showed that only 6.7% of low-risk PMC definitely became enlarged during 5 years of follow up, indicating that observation is an attractive alternative to surgery for PMC. However, PMC with clinically apparent metastasis detected on imaging is likely to show a recurrence to the lymph node and careful neck dissection as well as total thyroidectomy may be required. If surgical treatment is performed for low-risk PMC, prophylactic modified radical neck dissection is not necessary and lobectomy (with isthmectomy) and central node dissection is adequate if the tumor is located only in one lobe.

Prognosis of Patients with Benign Thyroid Diseases Accompanied by Incidental Papillary Carcinoma Undetectable on Preoperative Imaging Tests

BACKGROUND

Despite the recent wide availability of ultrasonography and fine-needle aspiration biopsy, endocrine surgeons often encounter incidental papillary carcinoma (IPC), that is a papillary carcinoma that had gone undetected by preoperative imaging studies but was identified by pathological examination of surgical specimens resected for benign thyroid diseases.

METHODS

The present study was developed to investigate the prognoses of 317 patients who underwent surgery for benign diseases involving IPC in comparison with the prognoses of 1,674 patients with clinically apparent papillary carcinoma detected preoperatively and diagnosed.

RESULTS

None of the patients underwent further surgery such as completion total thyroidectomy and node dissection immediately after the diagnosis of IPC. To date, 7 patients (2.2%) have had recurrences; 6 of those were locoregional recurrences and one was a bone metastasis. None of the patients have died of thyroid carcinoma. The disease-free survival of IPC patients was significantly better than that of clinically apparent papillary carcinoma patients and was similar to that of the subset of patients with papillary microcarcinoma without clinically apparent metastasis.

CONCLUSIONS

Because IPC is associated with good prognosis, further surgery, such as completion total thyroidectomy or lymph node dissection immediately after the diagnosis of IPC is not necessary.

A therapeutic strategy for incidentally detected papillary microcarcinoma of the thyroid

Papillary microcarcinoma of the thyroid (PMCT) is defined as papillary carcinoma measuring 1.0 cm or less. PCMT are frequently detected by ultrasonographic screening and ultrasonography-guided fine-needle aspiration biopsy. Although PMCT can pathologically show a high incidence of multifocality and lymph node metastasis in surgical specimens, most tumors grow slowly or not at all when they are monitored without surgery. In our observations only 6.7% of PMCT enlarged by 3.0 mm or more in diameter during 5 years of follow-up, and nodal metastases became detectable in 1.7% of patients overall. Observation without surgery could, therefore, be an attractive alternative for patients with low-risk PMCT; however, occult PMCT, which are diagnosed as the origin of lymph node or distant metastasis, show a worse prognosis. Even among incidentally detected PMCT, tumors with ultrasonographically detectable nodal metastasis are more likely to recur. Because such PMCT are most likely to recur in the regional lymph nodes, careful therapeutic neck dissection and total thyroidectomy are required. For incidentally detected and low-risk PMCT, careful observation without surgery might be acceptable, but careful and systematic surgery should be performed for patients with PMCT demonstrating aggressive characteristics.

Favorable surgical results in 433 elderly patients with papillary thyroid cancer

Papillary thyroid cancer (PTC) has a good prognosis among patients younger than 45 years old, but the prognosis in elder is worse and treatment strategy is not well established. We retrospectively analyzed the clinical features and outcomes of 433 patients with PTC aged 70 years or older. The patients consisted of three groups: group A (n = 327); patients receiving surgical treatment, group B (n = 51); patients with microcancer (maximal diameter, < or = 1.0 cm) who did not undergo surgical treatment, group C (n = 55); patients in whom surgery was contraindicated due to age, high surgical risk or complication by other illnesses. In group A, the mean tumor size was 2.6 +/- 1.5 cm, and 218 patients (66.7%) had pathologically confirmed lymph node metastasis; 110 patients (33.6%) had extrathyroidal invasion. The 5- and 10-year overall survival rates (OSR) in group A were 97.2% and 85%, respectively, which was significantly higher than the 5-year OSR in group C (62.6%). The 5- and 10-year disease-specific survival rates (DSSR) in group A were 98.5% and 91.3%, respectively, which was also significantly higher than the 5-year DSSR in group C (81.8%). Although the patients in group B did not receive any treatment, none of them demonstrated cause-specific death or progression of disease. Papillary thyroid cancer in elderly patients, except for microcancers, may be biologically aggressive. Thus surgery is recommended for these patients, if their general status is judged able to tolerate the stress of anesthesia and surgery.

Incidence trends for papillary thyroid carcinoma and their correlation with thyroid surgery and thyroid fine-needle aspirate cytology

CONTEXT

Papillary thyroid carcinoma (PTC) is the most prevalent endocrine malignancy. The reported incidence of PTC has more than doubled in many countries during the past half century. In Tasmania, an island state of the Commonwealth of Australia the incidence has increased by 24.7% per annum during the last two decades.

OBJECTIVE

Using the Tasmanian population as a model, this study sought to determine the relationship between changes in PTC incidence and trends for utilization of thyroid surgery and thyroid fine-needle aspiration biopsy (FNAB) cytology.

DESIGN

Hospital and pathology services in Tasmania provided data relating to all thyroid surgical, cytologic, and histopathology procedures undertaken between 1988 and 1998. The accuracy of PTC case ascertainment by the Tasmanian Cancer Registry was validated and the relationship between thyroid procedures and PTC incidence assessed.

RESULTS

A total of 3452 individuals underwent a thyroid procedure, comprising 1968 surgical and 1756 FNAB cytologic procedures. Of these, 184 patients were diagnosed with thyroid carcinoma, of whom 121 (65.8%) had PTC. Thyroidectomy and thyroid FNAB increased by 7.0% and 49.7% per annum, respectively. The likelihood of diagnosing PTC in thyroidectomy specimens increased by 99.7% per year in those patients preoperatively assessed by FNAB, compared to 10.1% per year in those for whom a preoperative FNAB was not performed. PTC incidence increased independently of PTC tumor size, although the greatest increase occurred for PTC 1 cm or less with a history of preoperative FNAB.

CONCLUSIONS

These results suggest increasing PTC incidence is largely attributable to greater diagnosis of small PTC, many of which are likely to have been asymptomatic, identified by neck ultrasonography and subsequent FNAB. However, the incidence of PTC larger than 1 cm in patients without history of preoperative FNAB has also risen, suggesting the occurrence of clinically relevant tumors may also have increased.

Prevalence of Thyroid Nodules and Carcinomas in Patients Operated on for Renal Hyperparathyroidism: Experience with 339 Consecutive Patients and Review of the Literature

The association between renal hyperparathyroidism (HPT) and differentiated thyroid carcinoma is discussed. To determine the prevalence and potential risk factors, we performed a retrospective analysis of our patients (1998-2004) and compared the data with the data from other surgical and autopsy studies. At our hospital, a total of 347 parathyroidectomies in 339 patients with renal HPT were performed. Most patients underwent preoperative ultrasound investigation of the thyroid gland and, if indicate, thyroid scintigraphy. Intraoperatively, both thyroid lobes were mobilized and palpated. Detected thyroid nodules were adequately resected and investigated histologically. A systematic analysis of the international literature was performed using the PubMed/MEDLINE system to identify publications on the prevalence of papillary thyroid carcinoma (PTC) in patients with renal HPT and in the overall population. Altogether, 133 patients (39.2%) underwent simultaneous thyroid surgery. The initial operation was hemithyroidectomy in 55 (16.2%), Dunhill operation in 36 (10.6%), unilateral subtotal resection in 17 (5.0%), bilateral subtotal resection in 5 (1.5%), and enucleation of a thyroid nodule in 18 (5.3%). A PTC was found in 8 of 339 patients (2.4%) and a follicular thyroid carcinoma in 1. Among 311 patients with primary cervical operation, 6 (1.9%) had a papillary thyroid carcinoma. All papillary tumors were classified as pT1 with a diameter of 1 to 12 mm; three were bifocal, and only one patient had positive lymph nodes. None of the analyzed factors showed a significant correlation with the occurrence of thyroid carcinoma. Depending on the screening method, the prevalence of occult PTC in European autopsy studies ranged from 5% to 9% and was markedly higher in almost all studies than in the present one. The prevalence of PTC in the present study makes an etiologic association between renal HPT and PTC unlikely. The clinical significance of these tumors remains unclear because all incidental tumors were small. However, if easily and safely feasible, relevant thyroid nodules should be removed during parathyroid surgery.

Temporal trends for thyroid carcinoma in Australia: an increasing incidence of papillary thyroid carcinoma (1982-1997)

The incidence of papillary thyroid carcinoma (PTC) has increased in many countries over the past 60 years. In Tasmania (an island state of the Australian Commonwealth with a well-documented history of iodine deficiency, subsequent supplementation and more recently a return to deficiency), there has been a fourfold rise in PTC incidence over the past two decades. The aim of this study was to evaluate thyroid carcinoma (TC) incidence trends in Australia, with particular reference to the roles of iodine nutrition, ionizing radiation, and ascertainment bias. Data from Australia's regional cancer registries were used to determine national TC incidence and mortality trends for the period 1982-1997. There were 9,053 new diagnoses of TC. Papillary, follicular, medullary, anaplastic, and "other diagnoses," accounted for 65.8%, 17.8%, 4.6%, 1.3%, and 10.5% of registered cases, respectively. TC incidence rates increased by 6.7% per year for females and 4.4% per year for males between 1982-1997 (p < 0.001). The increase was primarily because of a 10.7% per year and 8.3% per year rise in PTC incidence for females and males respectively (p < 0.001). The increase in PTC incidence was most significant for the population residing on Australia's eastern seaboard. The greatest relative and absolute increase in PTC (24.7% per year) occurred in Tasmania. These findings are consistent with a true increase in underlying PTC incidence rates. A link between current incidence trends and past iodine deficiency/radioiodine exposure during the 1950s and early 1960s is possible.

Latent carcinoma of the thyroid in Austria: a systematic autopsy study

Data concerning the incidence of latent thyroid carcinoma (LTC) in populations with endemic goiter are scarce. Despite the introduction of iodine goiter prophylaxis in the early sixties, iodine supply is still insufficient in Austria and goiter remains endemic. This is the first detailed study dealing with epidemiological features of LTC at autopsy in Austria. A total of 118 thyroid glands were included in the study. The glands were serially sectioned at 2- to 3-mm intervals, embedded in paraffin and histologically examined for the presence of LTC. In addition, the incidence and severity of lymphocytic thyroiditis (LT) were evaluated. Ten thyroids were found to contain LTC (8.6%). All were of the papillary type. The mean tumor dimension was 4.9 mm +/- 3.2, the smallest lesion measuring 1 mm. Only the largest tumor slightly exceeded the extent of a microcarcinoma and measured 10.5 mm. Multifocal disease was present in three cases (30%). The prevalence of latent papillary thyroid carcinoma (LPTC) was 6.6% (n = 4) in females and 10.5% (n = 6) in males. The mean age of the subjects with LPTC was 67.7 +/- 14.4 yr, range 37 to 77 yr. Goitrous thyroids were seen in 33 cases (28%): One gland was diffusely enlarged and 32 (27.1%) enlarged glands were nodular goiters. The overall prevalence of LT was 30.5% (n = 36) and the only type of thyroiditis observed was focal lymphocytic thyroiditis (FLT). There was no correlation between the presence of LPTC and goiter, the presence of FLT and the subjects' age and sex. The incidence of LPTC in Austria is similar to that in nongoitrous regions. The adult population at large seems to be uniformly exposed to factors involved in the initiation and early growth of papillary thyroid carcinoma (PTC). This suggests that the levels of iodine intake only play a minor role in the early phase of the carcinogenesis of PTC, but may be of some importance in the progression of LPTC to clinically evident PTC.

Medullary thyroid microcarcinoma: a clinicopathologic retrospective study of 38 patients with no prior familial disease

Thirty-eight patients (25 women, 13 men; mean age, 57.8 [32 to 91]) showing one or more medullary thyroid microcarcinomas (ie, < 1 cm), with no prior MEN II or medullary thyroid carcinoma history in their family, were reviewed. Follow-up was available for 29 patients (mean, 53.6 months [1 to 147]). 21 patients (72.4%) are alive and free of disease, four patients (13.8%) died during follow-up without disease, 2 patients are alive with disease (local recurrence and persistent hypercalcitoninemia) after 80 and 99 months, respectively, and 2 patients died of disease after 24 and 46 months. Most tumors were incidental pathological findings (19 of 38) or were discovered by systematic blood calcitonin measurement for a nodular thyroid disease (15 of 38). Only the four patients who had an unfavorable outcome were symptomatic cases (palpable micro-MTC, diarrhea, cervical lymph node metastasis and pulmonary metastatic disease). The two patients with metastatic disease at diagnosis died during follow-up. In univariate analysis, a symptomatic medullary thyroid carcinoma was a strong predictor of an unfavourable outcome (p < .00008), as were the preoperative calcitonin level (P = .007) and an elevated postoperative calcitonin level (P = .004). Among 30 histopathological criteria, only the presence of amyloid correlated with an unfavorable outcome (P = .018).

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.

Incidence and clinical characteristics of thyroid carcinoma after iodine prophylaxis in an endemic goiter country

Iodized salt prophylaxis has been performed in Austria since 1963. Through this approach, mean urinary iodine excretion has been normalized to 144+/-23.5 microg/g creatinine per day. Thus Tyrol is no longer an endemic goiter area. We have analyzed the impact of iodized salt prophylaxis on thyroid cancer (TC) comparing data from the early 1960s with those corresponding to the period 1986 to 1995, when iodine supply was normalized. The study included 439 patients from Tyrol and Southern Tyrol. The incidence of TC in Tyrol has risen during the past decades from 3.07 between in 1957 and 1970 to 7.8 between 1990 and 1994 (CR/100000/year). We observed a rise in the percentage of differentiated adenocarcinomas (56% to 91.5%) with a predominance of papillary TC (54.4%) along with a decrease of anaplastic TC. In addition to these histological features, a shift to less advanced TNM stages, eg, T1-3, N0-1a, M0, was obvious, increasing from 29% to 72.2%, whereas advanced tumors, ie, T4 or N1b or M1, decreased from 71% to 28%. These changes have significantly improved prognosis. The current 5-year survival rate is 90.7% as compared with a rate of 73% in the 1960s; the values for 7-year survival are 89% and 48%, respectively. The marked effects of age, tumor stages, and histology on prognosis were confirmed with the Kaplan-Meier method. We conclude that together with normalization of iodine supply in an endemic goiter region the epidemiological profile of TC has changed. Even though the incidence of TC has risen, prognosis has significantly improved due to a shift towards differentiated forms of TC that are diagnosed at earlier stages.