Increased risk of thyroid cancer among Norwegian women married to fishery workers--a retrospective cohort study

Development and validation of a nomogram to predict cancer-specific survival in middle-aged patients with papillary thyroid cancer: A SEER database study

Background

Thyroid cancer (TC) accounts for more than 90% of endocrine tumours and is a typical head and neck tumour in adults. The aim of this study was to develop a predictive tool to predict cancer-specific survival (CSS) in middle-aged patients with papillary thyroid carcinoma (PTC).

Methods

The patients from 2004 to 2015 were randomly divided into a training cohort (n = 25,342) and a internal validation cohort (n = 10,725). The patients from 2016 to 2018 were treated as an external validation cohort (n = 11353). COX proportional hazard model was used to screen meaningful independent risk factors. These factors were constructed into a nomogram to predict CSS in middle-aged patients with PTC. The performance and accuracy of the nomogram were then evaluated using the concordance index (C-index), calibration curve and the area under the curve (AUC). The clinical value of nomogram was evaluated by decision curve analysis (DCA).

Results

Age, gender, marriage, tumour grade, T stage, N stage, M stage, surgery, chemotherapy, and tumour size were independent prognostic factors. The C-indexes of the training, internal validation, and external validation cohorts were 0.906, 0.887, and 0.962, respectively. The AUC and calibration curves show good accuracy. DCA shows that the clinical value of the nomogram is higher than that of Tumour, Node and Metastasis (TNM) staging.

Conclusion

We developed a new prediction tool to predict CSS in middle-aged patients with PTC. The model has good performance after internal and external validation, which can be friendly to help doctors and patients predict CSS.

A nested case-control study of polychlorinated biphenyls, organochlorine pesticides, and thyroid cancer in the Janus Serum Bank cohort

BACKGROUND

Polychlorinated biphenyls (PCBs) and organochlorine pesticides have been associated with altered thyroid hormone levels in humans, but their relationship with thyroid cancer is unknown.

METHODS

We conducted a nested case-control study of thyroid cancer in the Norwegian Janus Serum Bank cohort using pre-diagnostic blood samples from 1972 to 1985. Incident thyroid cancer (n = 108) was ascertained through 2008. Controls were matched 2:1 by age, date of blood draw, gender, and county. We used gas chromatography/mass spectrometry to quantify 36 PCB congeners and metabolites of pesticides DDT, chlordane, hexachlorocyclohexane, and hexachlorobenzene. PCBs and pesticide metabolites were evaluated individually and summed by degree of chlorination and parent compound, respectively. Odds ratios (OR) and 95% confidence intervals (CI) were computed using conditional logistic regression per specified increase in lipid-adjusted concentration. We additionally stratified analyses by birth cohort (1923-1932, 1933-1942, 1943-1957).

RESULTS

Increasing concentration of DDT metabolites (OR_{per 1000 ng/g} = 0.80, 95%CI = 0.66-0.98) was inversely associated with thyroid cancer. Associations for PCBs were null or in inverse direction. We observed interactions for total PCBs, moderately-chlorinated PCBs, and chlordane metabolites with birth cohort (p ≤ 0.04). Among participants born 1943-1957, total PCBs (OR_{per 100 ng/g} = 1.25, 95%CI = 1.00-1.56), moderately-chlorinated PCBs (OR_{per 100 ng/g} = 1.31, 95%CI = 1.01-1.70), and chlordane metabolites (OR_{per 10 ng/g} = 1.78, 95%CI = 1.09-2.93) were positively associated with thyroid cancer. For individuals born before 1943, associations were generally null or in the inverse direction.

CONCLUSIONS

Emissions of PCBs and OC pesticides varied over time. Different risk patterns by birth cohort suggest the potential importance of timing of exposure in thyroid cancer risk. Further evaluation of these associations is warranted.

Protocol of a thyroid cancer longitudinal study (T-CALOS): a prospective, clinical and epidemiological study in Korea

INTRODUCTION

Thyroid cancer incidence in Korea is the highest in the world and has recently increased steeply. However, factors contributing to this sudden increase have not been fully elucidated, and few studies have explored the postoperative prognosis. The Thyroid Cancer Longitudinal Study (T-CALOS) was initiated with three aims: (1) to identify factors predicting quality of life, recurrence, and incidence of other diseases after thyroid cancer treatments; (2) to investigate environmental exposure to radiation, toxicants and molecular factors in relation to tumour aggressiveness; and (3) to evaluate gene-environment interactions that increase thyroid cancer in comparison with healthy participants from a pool of nationwide population-based healthy examinees.

METHODS AND ANALYSIS

T-CALOS enrols patients with incident thyroid cancer from three general hospitals, Seoul National University Hospital, Seoul National University Bundang Hospital and National Medical Center, Korea. The study is an ongoing project expecting to investigate 5000 patients with thyroid cancer up until 2017. Healthy examinees with a normal thyroid confirmed by sonography have been enrolled at the Healthy Examination Center at Seoul National University Hospital. We are also performing individual matching using two nationwide databases that are open to the public. Follow-up information is obtained at patients' clinical visits and by linkage to the national database. For statistical analysis, we will use conditional logistic regression models and a Cox proportional hazard regression model. A number of stratifications and sensitivity analyses will be performed to confirm the results.

ETHICS AND DISSEMINATION

Based on a large sample size, a prospective study design, comprehensive data collection and biobank, T-CALOS has been independently peer-reviewed and approved by the three hospitals and two funding sources (National Research Foundation of Korea and Korean Foundation for Cancer Research). The results of T-CALOS will be published according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria.

The impacts of organochlorines and other persistent pollutants on thyroid and metabolic health

High prevalence of thyroid and metabolic disorders has been repeatedly observed in the population living in the area of eastern Slovakia highly polluted by a mixture of PCBs, DDE and HCB since about 50 years ago. Among thyroid disorders, increase of thyroid volume as measured by ultrasound volumetry may be suggested as one of notable findings which appeared possibly related to increased OCs levels and to autoimmunity signs (e.g. positive thyroperoxidase antibodies in blood and/or hypoechogenicity image obtained by ultrasound), while some participation of individual susceptibility and also of immunogenic effect of OCs and iodine in this iodine replete country cannot be excluded. Another notable finding has been the increase of blood FT4 and TT3 positively related to high PCBs level. Such increased FT4 level has been found associated with TSH level in hyperthyroid range in about 2% of examined population from polluted area. High prevalence of thyroid autoimmune disorders strongly supported the assumption on impaired immune system and thus also on presumably increased prevalence of other autoimmune disorders in highly exposed population. In addition, markedly increased prevalence of prediabetes and diabetes significantly related to major OCs (PCBs, DDE and HCB) levels and accompanied by increasing level of cholesterol and triglycerides has been observed. The observations also suggested a role of prenatal exposure to OCs in the development of several adverse health signs (e.g. increased prevalence of thyroid antibodies, impaired fasting glucose level, increased thyroid volume, decreased thymus volume, decreased neurobehavioral performance, increased hearing and dental disorders) in young generation born to highly exposed mothers in polluted area.

Effect of long-term administration of arsenic (III) and bromine with and without selenium and iodine supplementation on the element level in the thyroid of rat

The aim of this study was to evaluate the influence of arsenic and bromine exposure with or without iodine and selenium supplementation on the element level in the thyroid of rats. Four major groups of Wistar female rats were fed with respective diets: group A - standard diet, group B - iodine rich diet (10 mg I/kg food), group C - selenium rich diet (1 mg Se/kg) and group D - iodine and selenium rich diet (as in group B and C). Each group was divided into four subgroups per 7 animals each receiving either NaAsO(2) ip (6.5 mg.kg(-1) twice a week for two weeks and 3.25 mg.kg(-1) for six weeks) or KBr in drinking water (58.8 mg.l(-1)) for 8 weeks or combined administration of both substances. Remaining subgroup served as controls. After 8 weeks thyroid glands were analyzed by ICP-MS for As, Br, Se, and I content. The exposition of rat to arsenic or bromine causes the accumulation of these elements in the thyroid gland ( approximately 18 ppm of As, approximately 90 ppm of Br) and significantly affects iodine and selenium concentration in the thyroid. In iodine and/or selenium supplemented rats the bromine intake into the thyroid was lowered to approximately 50% of the level in unsupplemented animals. Also selenium thyroid level elevated due to KBr administration was lowered by iodine supplementation in the diet. The accumulation of arsenic in the thyroid was not influenced by selenium or iodine supplementation; however, As(III) administration increased iodine thyroid level and suppressed selenium thyroid level in selenium or iodine supplemented group of animals.

Primary thyroid malignancies in Tehran, Iran

OBJECTIVE

The aim of this study was to present a descriptive epidemiology of primary thyroid cancer in Tehran, Iran, using cancer registry data.

SUBJECTS AND METHODS

All cases of thyroid cancer registered from 1998 to 2001 in Tehran Metropolitan Area Population-Based Cancer Registry were used for this study. The incidence of thyroid cancer was estimated for the area covered by the cancer registry. Survival of patients was ascertained by telephone call to the patients or the patient's family and/or linkage of registry data to mortality data from the Bureau of Vital Statistics. Patient's survival was based on sex, age and morphological type of tumour.

RESULTS

Four hundred and twenty-nine cases of primary thyroid cancer were registered in the Tehran Metropolitan Area Cancer Registry. The incidence of thyroid cancer was 3.5 and 1.0 per 100,000 population per year for females and males, respectively. Seventy percent of tumours were papillary, 11% follicular, 6.2% medullary, and the rest were other subtypes. The papillary and follicular variants occurred in younger age: 43 +/- 16 and 46 +/- 13 years, respectively; the medullary and anaplastic variants occurred in older age: over 50 years. A 5-year survival rate was 82.2%, with median survival of 66 months and 95% confidence interval of 63 and 69 months. Men and women had a similar survival experience.

CONCLUSIONS

While the incidence of thyroid cancer was slightly high, the descriptive epidemiology of thyroid cancer in Tehran did not manifest a unique feature. Tehran patients experienced a high rate of survival, and the survival time for males and females was similar.

The influence of dietary patterns on the development of thyroid cancer

To elucidate the role of diet in the development of thyroid cancer, we conducted a case-control study of 113 persons with histologically-verified thyroid cancer and 138 controls, matched by age, gender and health unit. Socio-economic data, known risk factors and food consumption of more than 100 items were recorded by interviewer-administered prestructured questionnaire. Factor analysis was used to identify possible dietary patterns and logistic regression analysis was used to explore the effect of food items or dietary patterns on thyroid cancer. After adjustment for age, gender, body mass index (BMI), and total energy intake, significant positive associations were observed for pork consumption, while negative ones were observed for tomatoes, lemons and pasta. Dietary patterns of fruits, raw vegetables and mixed raw vegetables and fruits, led to a reduced risk (corresponding odds ratios (ORs) 0.68, 0.71, 0.73) for all thyroid cancers and similar figures were obtained for papillary thyroid cancers. A dietary pattern of fish and cooked vegetables led to an increased risk (OR 2.79) of follicular cancer.

Cancer incidence among a cohort of female farm residents in New York State

A retrospective cohort study of cancer incidence among 6,310 female farm residents who were New York Farm Bureau members, or members' spouses or relatives, was conducted from 1980 through 1993. Similar to the previous findings for New York State male farmers, the female farm resident cohort experienced significantly lower cancer rates for all cancers combined, and for lung cancer, compared with rural nonfarm female residents. In addition, significantly low rates for colorectal cancer and ovarian cancer were found among the female cohort members. Nonsignificant excesses were found for thyroid and liver cancers. The findings suggest that female farm residents in this cohort might have experienced some of the same cancer-protective factors as male farmers.

The epidemiology and etiology of differentiated thyroid carcinoma

Differentiated thyroid carcinoma (DTC) is a rare tumor with a relatively good prognosis, but in about 10% of cases it may be the cause of death. Papillary carcinoma is more frequent (about 70-80% of cases) and less aggressive than follicular cancer: the papillary/follicular ratio is increased in areas of high iodine intake. In recent years many genes have been found to be mutated in DTC, the most important of these being ras, ret, trk, and met. The relationship between radiation exposure and DTC is well recognized, especially in children. Since the Chernobyl nuclear accident, a high incidence of DTC has been found in children exposed to fallout.

Advances in the pathogenesis and treatment of thyroid cancer

Thyroidectomy remains the mainstay of treatment for thyroid carcinoma. The extent of surgical resection, however, remains controversial as most patients will have excellent long-term prognosis and because some of the standard staging and prognostic information are not available at the time of surgical resection. The different staging and risk group definitions for thyroid carcinoma are not superior to the Tumor-Node-Metastasis classification of the American Joint Commission in Cancer (AJCC), which is universally available and accepted and should be used to report treatment outcomes. Recent advances in the molecular pathogenesis of thyroid malignancy will help identify high-risk patients who would benefit from aggressive surgical resection and adjuvant treatment.