Descriptive epidemiology of thyroid cancer in the Swiss Canton of Vaud

Core needle biopsy for thyroid nodules assessment-a new horizon?

Ultrasound-guided fine-needle aspiration is the standard for evaluating thyroid nodules with a high safety profile and a relatively low number of non-diagnostic cytological findings. Nevertheless, this diagnostic method traditionally has its weak points. Several diagnostic categories such as Bethesda I, III and IV are not reliable for thyroid carcinoma risk assessment. Recent advancements in a core needle biopsy made it possible to use this tool as a new method for thyroid nodules evaluation. The main feature of this method is the use of thin needles (18-21G) and guns with an automatic trigger mechanism. The histological material collected with the use of a core needle biopsy is usually superior to cytological. Therefore, the core needle biopsy can be used as a complementary technique to a standard fine needle aspiration in difficult and dubious cases of thyroid neoplasia with uncertain malignant potential.

The association between the socioeconomic status and thyroid cancer prevalence; based on the Korean National Health and Nutrition Examination Survey 2010-2011

The incidence of thyroid cancer has recently increased in most industrialized countries, including Korea. To date, few studies have examined the association between thyroid cancer and socioeconomic status (SES). The current study was based on data collected from a total of 12,276 subjects (5,277 men and 6,999 women) by the Korean National Health and Nutrition Examination Survey (KNHANES) between 2010 and 2011. Univariate and multivariate logistic regression analysis revealed that older age (odds ration [OR], 1.03; 95% confidence interval [CI], 1.00-1.05), being female (OR, 8.16; 95%CI, 2.99-22.24), being overweight (OR, 1.04; 95%CI, 1.01-1.06), monthly household income (OR, 3.27; 95%CI, 1.16-9.20 for medium-highest household income vs lowest household income; OR, 3.30; 95%CI, 1.16-9.34 for highest household income vs lowest household income), educational level (OR, 2.74; 95%CI, 1.16-6.46 for 10-12 yr vs < 7 yr) and alcohol consumption (OR, 1.89; 95%CI 1.08-3.32) were significant risk factors for thyroid cancer. Our results indicate that the recent increase in thyroid cancer is attributable to better early detection rather than to any increase in actual prevalence.

Gender differences in thyroid cancer: a critical review

It has long been known that the incidence of thyroid cancer in women is significantly higher than that in men. The objective of this article is to review gender differences in thyroid cancer, as well as epidemiological, clinical and experimental research on the role of sex hormones, their receptors and other molecular factors in this well-established thyroid cancer gender discrepancy. Although more common in women, thyroid cancer typically presents at a more advanced stage and with a worse disease prognosis in men. Clinical evidence on the impact of estrogen and other sex hormones on thyroid cancer has remained inconclusive, although numerous experimental studies have suggested that these hormones and their receptors may play a role in tumorigenesis and tumor progression. Studies of thyroid cancer cell lines suggest that an imbalance between the two estrogen receptor (ER) isoforms, α and β, may be responsible for the cell proliferation seen with estrogen treatment. Expression studies on thyroid tumors indicate that they express ER and possibly progesterone receptors and androgen receptors, but there is conflicting evidence as to whether or not there is a difference in receptor status between thyroid cancers, benign thyroid lesions and normal thyroid tissue. There have been few studies evaluating the ERα/ERβ profiles in thyroid tumors and normal thyroid tissue. Our understanding of the underlying basis for sex differences in thyroid cancer has improved over the last few decades, but the relationship between gender and thyroid cancer risk has remained elusive. Areas for future research include ERα/ERβ profiling of normal and neoplastic thyroid tissue, association between ER status and tumor dedifferentiation, and evaluation of the signaling pathways by which estrogen and other sex steroids exert their effects on thyroid cancer cells. Sex steroid receptors, and then downstream signaling pathways, represent promising future therapeutic targets for thyroid cancer treatment, and further study is required.

Descriptive epidemiology of thyroid carcinoma in Carinthia, Austria: 1984-2001. Histopathologic features and tumor classification of 734 cases under elevated general iodination of table salt since 1990: population-based age-stratified analysis on thyroid carcinoma incidence

INTRODUCTION

The aim of the study was to investigate the current thyroid carcinoma (TC) incidence in Carinthia, a former iodine-deficient, goiter-endemic region in Austria with approximately 550,000 inhabitants from 1984 to 2001. Using age-cohort analysis we analyzed the TC incidence under the impact of two regional risk factors: the contamination of Austrian soils by the radioactive fallout in from Chernobyl 1986 and the increased iodination of table salt in a general program of goiter prophylaxis begun in 1991. To evaluate the characteristics of TC incidence, we compared the results of the periods 1984-1989, 1990-1995, and 1996-2001.

RESULTS

A total of 734 TC cases were diagnosed. Papillary, follicular, medullary, oxyphilic, and anaplastic TC accounted for 76%, 18%, 3%, 1%, and 2%, respectively. The female to male ratio was 3:1. The annual incidence rate increased by 8.05% in females and 11.6% in males. TC cases younger than 40 years of age accounted for 22.6%, with a rate increase of 18% per year in young males, the female-to-male ratio decreased from 8.3, 6.1, 2.7 younger than 40 in the compared periods. Along with a further increase in papillary TC incidence and papillary thyroid carcinoma (PTC) follicular thyroid carcinoma (FTC) ratio in the adult population, the ratio tended to decrease in the younger than 40-year-old population. T4 class TC and loco-regional lymph node involvement increased significantly.

INTERPRETATION

The observed changes in TC incidence, particularly in the young population, as in adults, could be linked to the abovementioned risk factors involved in the initiation and early growth of TC, and iodine may play a role in stimulating overall thyroid activity.

Changes in Clinical Presentation, Management and Outcome in 1348 Patients with Differentiated Thyroid Carcinoma: Experience in a Single Institute in Hong Kong, 1960–2000

The clinical features, management and outcome of 1348 patients diagnosed with differentiated thyroid carcinoma in Queen Elizabeth Hospital, Hong Kong, were analysed according to the period of diagnosis: A (before 1980), B (1981-1990) and C (1991-2000). As time advanced, ratio of papillary carcinoma (PTC) to follicular carcinoma (FTC) increased (A:B:C = 1.6: 3.1: 7.2). The mean size of the primary tumour decreased (A:B:C = 3.5 cm: 2.8 cm: 2.5 cm), with a greater percentage of microcarcinoma of 1 cm or less (A:B:C = 5.1%: 16.1%: 21.7%). At presentation, the incidence of lymph-node metastasis decreased (A:B:C = 32.7%: 31.6%: 24.8%) and that of distant metastasis decreased (A:B:C = 9%: 6.1%: 5.3%). Bilateral surgical resection was more commonly used (A:B:C = 62.8%: 89.1%: 94.8%) than lobectomy (A:B:C = 26.3%: 2.8%: 1.8%). Radiation treatment, radioactive iodine (131I; RAI) and external radiotherapy (EXT), was more commonly used (A:B:C = 53.2%: 74.7%: 85.1%). RAI was used in 84.3% (A:B:C = 50%: 71.2%: 84.3%) and EXT in 14.5% of patients in the past decade (A:B:C = 10.9%: 8.7%: 14.5%). The proportion of patients who adopted a bilateral surgery and RAI treatment increased gradually with time (A:B:C = 33%: 68%: 83.8%). The 5-year cause-specific survival (A:B:C = 90.2%: 93.7%: 95.7%), locoregional failure-free survival (A:B:C = 72.6%: 82.9%: 91.6%) and distant metastasis failure-free survival (A:B:C = 84.5%: 89.1%: 92.6%) were improved. However, the period of diagnosis was not found to be an important explanatory variable (i.e. P > 0.05) in Cox regression after adjusting for other factors, indicating that the improvement was probably related to the temporal trend of other factors: presentation at earlier stage, increased ratio of PTC:FTC and more aggressive management by bilateral surgery and radiation therapy.

Thyroid cancer in Vaud, Switzerland: an update

We reviewed the descriptive epidemiology of thyroid cancer using data from the Cancer Registry of the Canton of Vaud, Switzerland, a consistently well-surveilled population with relatively high rates of the disease, between 1974 and 1998, on the basis of a total of 596 registered cases. Overall thyroid cancer incidence tended to increase moderately in both genders over the 25-year period considered, to reach rates of 5.4 and 2.0 per 100,000 (world standard) in females and males, respectively. There were also changes in histologic classification, with some increases in papillary neoplasms and corresponding decreases in other and unclassified ones. Ten-year relative survival rates for cases diagnosed in 1988-1993 were 94% for papillary cancer in females and 69% in males, and 59% for follicular cancer in females. Corresponding figures were 12% for undifferentiated, and 31% for other and unspecified neoplasms in both sexes combined. Multivariate analysis confirmed the unfavorable influence of male gender (hazard ratio [HR] = 1.9), elderly age (HR = 16.5 for age > or = 65 vs. < 45 years) and undifferentiated histotype (HR = 3.5 vs. papillary) on the long-term prognosis of thyroid cancer, and showed no consistent evidence of appreciably improved prognosis over more recent calendar periods.

Cohort study of thyroid cancer in a San Francisco Bay area population

Using data from a large health plan, we performed a cohort study of thyroid cancer among 204,964 persons (aged 10--89 at baseline in 1964--1973, 54% female) followed for a median of 20 years. There were 196 incident thyroid cancers (73 in men, 123 in women). Risk was independently and positively related to female gender [relative risk (RR) = 1.56, 95% confidence interval (CI) = 1.12--2.19], Asian race (RR = 2.86, 95% CI = 1.76--4.65), completed college or post-graduate education (RR = 1.76, 95% CI = 1.20--2.59), history of goiter (RR = 3.36, 95% CI = 1.82--6.20), radiation of the neck region (RR = 2.33, 95% CI = 1.28--4.23) and family history of thyroid disease (RR = 2.18, 95% CI = 1.17--4.05). An inverse association was found for black race (RR = 0.55, 95% CI = 0.33--0.91). Cigarette smoking, alcohol consumption, personal history of hyperthyroidism, hypothyroidism, overweight or obesity, weight gain since age 20, height, occupational exposures, reproductive factors, oral contraceptives and hormone use did not show statistically significant relations to thyroid cancer. These results provide further evidence for a role of female gender, radiation, goiter, Asian race, high educational attainment and family history of thyroid disease in the etiology of thyroid cancer.

The relative roles of endemic goiter and socioeconomic development status in the prognosis of thyroid carcinoma

BACKGROUND

It generally is accepted that the prognosis of thyroid carcinoma is more severe in areas in which goiter is endemic. It could be assumed that this prognosis also is less favorable in developing countries.

METHODS

Clinical features and tumor histology of 1000 consecutive patients were studied: Patient data from the endemic area (EA) were compared with those from the nonendemic area (NEA). In addition, patients from the years 1966-1981 (P1) were compared with those from 1982-1991 (P2). It is obvious that the country's socioeconomic status and health care system improved between the two periods.

RESULTS

The anaplastic and follicular types of thyroid carcinoma were more frequent in EAs (14% and 42.13%, respectively) than in NEAs (6.25% and 38.40%, respectively). The frequency of the anaplastic carcinoma during P1 (16.03%) decreased by half during P2 (7.79%), whereas the frequency of follicular carcinoma remained stable (35.85% and 40.46%, respectively). Clinically, more advanced stages (tumor size, local and distant disseminations) were observed in the study country than in developed countries. A clearcut improvement was observed during P2 whereas differences between the EA and NEAs were few. Survival rates (follicular and papillary types only) were not found to be different between EAs and NEAs (5-year survival: 81.44% and 75.32%, respectively; 10-year survival: 67.93% and 69.52%, respectively). A significant (P < 0.01) increase was observed between P1 and P2 (5-year survival: 72.69% and 84.80%, respectively; 10-year survival: 58.77% and 83%, respectively).

CONCLUSIONS

Compared with endemic goiter, low socioeconomic status appeared to be the major factor accountable for the high prevalence of advanced stage cases and anaplastic carcinomas. Iodine deficiency appeared to play a specific role in the increased prevalence of follicular types of thyroid carcinoma.

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.

Thyroid cancer histotype changes as observed in a major general hospital in a 21-year period

The existing registries of thyroid carcinoma are seldom comparable as far as epidemiological data, diagnostic criteria and histopatological description are concerned. Epidemiological studies report a progressive increase in the incidence of thyroid carcinoma in the last twenty years and in both sexes this increase of incidence has been referred to papillary histotype. Data collected from surgical series show a rate of thyroid carcinomas from 7 to 20% of total thyroid surgeries. The present study was designed in order to obtain a retrospective review of the distribution of thyroid carcinoma's different histotypes in the last 21 years in a major General Hospital. Detailed analysis of patients with histologically confirmed thyroid carcinoma admitted between 1974 and 1994 to the Surgery Department of Mauriziano Hospital of Torino, Italy showed an overall 11.8% prevalence of thyroid cancer out of the total thyroid surgeries. The rate of papillary carcinoma was the highest (54.3%) followed by follicular carcinoma (27.6%), anaplastic carcinoma (11.1%), medullary carcinoma (4.6%) and others (2.4%). The papillary-to-follicular ratio varied from 0.60 in 1974-76 to 6.88 in 1992-94. Female to male ratio of all thyroid carcinoma histotypes was 2.0 or more; papillary and follicular histotypes had the highest ratio. The variations of the histotype rate observed may be consequence of the silent increase of daily iodine intake throughout the subsequent years, while improved diagnostic tools available and increased experience of the medical staff have probably increased the number on thyroid ablations performed. Our data confirm the changing epidemiology of thyroid carcinoma, reported by international literature.

Education and cancer risk

BACKGROUND

Socioeconomic factors have been associated, to a variable degree, with the risk of serious cancers.

METHODS

The relationship between education and cancer risk was analyzed using data from a series of case-control studies conducted in northern Italy between 1983 and 1990, including 119 histologically confirmed cancers of the oral cavity and pharynx, 294 of the esophagus, 564 of the stomach, 673 of the colon, 406 of the rectum, 258 of the liver, 41 of the gallbladder, 303 of the pancreas, 149 of the larynx, 2860 of the breast, 692 of the cervix, 567 of the corpus uteri, 742 of the ovary, 107 of the prostate, 365 of the bladder, 147 of the kidney, and 120 of the thyroid, 72 Hodgkin diseases, 173 non-Hodgkin lymphomas, 117 myelomas, and a total of 6147 control subjects admitted to the same network of hospitals for acute, non-neoplastic conditions.

RESULTS

Nine types of cancer were inversely related to education. Those were oral cavity and pharynx, with a relative risk (RR) of 0.3 for the highest versus the lowest level; esophagus, RR = 0.6; stomach, RR = 0.5; liver, RR = 0.7; gallbladder, RR = 0.5; larynx, RR = 0.3; cervix, RR = 0.7; endometrium, RR = 0.5; and non-Hodgkin lymphomas, RR = 0.6. Five cancer sites were directly related to education: colon, RR = 1.3; pancreas, RR = 1.3; breast, RR = 1.5; kidney, RR = 1.3; and thyroid, RR = 1.5. No consistent gradient in risk with education was observed for the six other neoplasms considered, including rectum, prostate, bladder, Hodgkin disease, and multiple myeloma. The patterns of risk for education were consistent in men and women for most cancer sites except colon, for which the direct relationship was stronger in males.

CONCLUSIONS

This study confirms the existence of and quantifies a number of strong socioeconomic correlates of cancer risk and indicates a few points open to additional investigation, such as the different pattern of risk for rectal and colon cancer, the strong negative gradient for endometrial cancer, and the absence of any clear association with education for cancers of the ovary, prostate, urinary tract, lymphomas, and myeloma.

Previous thyroid disease and risk of thyroid cancer in Switzerland

A hospital-based case-control study of 86 cases of thyroid cancer and 317 controls was done in the Swiss Canton of Vaud. Patients with thyroid cancer tended to be better educated (odds ratio [OR] 2.1 for greater than or equal to 14 vs. less than or equal to 8 years of education 95% CI 1.1-4.1) and of higher social class than controls. Cases more often had a history of benign thyroid nodules (OR 25.2, 95% CI 7.6-83.6) and non-toxic goitre (OR 5.3, 95% CI 2.5-11.2). Furthermore, patients with thyroid cancer were more likely to have resided in endemic goitre areas (OR 1.7, 95% CI 1.0-3.0) and to have had first-degree relatives affected by benign thyroid disease (OR 3.9, 95% CI 2.1-7.1). Therefore, this study offers quantitative evidence of the association between various thyroid diseases and the risk of thyroid cancer which, despite difficulties in the classification of benign and malignant thyroid diseases, is remarkably consistent in studies from different countries.