Does Chernobyl accident have any effect on thyroid cancers in Turkey? A retrospective review of thyroid cancers from 1982 to 2006

Deciphering novel biomarkers of lymph node metastasis of thyroid papillary microcarcinoma using proteomic analysis of ultrasound-guided fine-needle aspiration biopsy samples

Thyroid papillary microcarcinoma is now a common clinical problem. Cervical lymph node metastasis is the main metastasis mode of PTMC. However, before operation, it is still difficult to determine exactly whether PTMC patient is suffering with cervical lymph node metastasis. To resolve this dilemma, for better selection of optimum treatment plans, it is necessary to investigate the overall changes in proteomes of PTMC, and evaluate the potential of biomarkers to predict lymph node metastasis. Tandem mass tags combined with multidimensional liquid chromatography and mass spectrometry analyses were used aiming to screen the proteomic profiles of fine-needle aspiration biopsy samples. Quantitative proteomic analysis, significant pathway and functional categories were investigated. In total, 3391 proteins of the 3793 protein groups identified were quantified. Bioinformatics analysis indicated that differentially expressed proteins were involved in multiple biological functions, metastasis-related pathways. Moreover, IFN-stimulated gene 15 proteins were found to be well distinguished between patients with lymph node metastatic and patients with nonmetastatic PTMC. Knocking down ISG15 with shRNA inhibited the xenografted tumor growth. This study provided a reference proteome map for lymph node metastatic PTMC. ISG15 probably is a prognosis marker of thyroid papillary microcarcinoma patients with lymph node metastasis. SIGNIFICANCE: Nowadays, thyroid cancer has become a widespread epidemic. The rate of thyroid cancer incidence has been faster than any other cancers, reported by the American Cancer Society. Papillary thyroid microcarcinoma (PTMC) is a subset of PTC defined as PTC measuring≤1 cm in size, which comprises nearly one-half of all the cases of PTCs. Actually, the rapidly increasing global incidence of PTC is mainly attributed to the corresponding increase in the diagnosis of PTMC. Scholars have figuratively compared the increase of PTMC to the "tsunami". The treatment scheme for PTMC is still not uniform, and the controversy is mainly focused on the necessity of surgery treatment. PTMCs often have an indolent course in the absence of evidence of metastatic cervical lymph nodes, distant metastases and extrathyroidal extension. Therefore, it is important for us to reliably differentiate the small number of PTMC patients developing significant metastases progression from the larger population of patients that harbor indolent PTMCs. The present study aimed to investigate the overall changes in proteomes of PTMC, and evaluate the potential of biomarkers to predict lymph node metastasis. Tandem mass tags (TMT) combined with multidimensional liquid chromatography and mass spectrometry analyses were used aiming to screen the proteomic profiles of fine-needle aspiration biopsy (FNAB) samples. Quantitative proteomic analysis, significant pathway and functional categories were investigated. Our results showed that some differential expression proteins were likely to be important resources for finding new diagnostic biomarkers.

Prevalence of papillary thyroid cancer in subacute thyroiditis patients may be higher than it is presumed: retrospective analysis of 137 patients

Background The association of subacute thyroiditis (SAT) and papillary thyroid carcinoma is a rare finding. In this study, we aimed to investigate the prevalence of differentiated thyroid cancer in a cohort of patients followed with the diagnosis of SAT. Patients and methods We retrospectively screened medical records of Endocrinology and Metabolism outpatient clinic in the past 20 years for patients with SAT. Patients with nodules and suspicious ultrasonography findings who underwent fine needle aspiration biopsy (FNAB) and operated due to malignancy risk were identified. Results We identified 137 (100 females, 37 males) patients with reliable records to confirm the diagnosis of SAT. The mean age of female patients was 41.1 ± 9.1 (range, 20-64) and of male patients was 43.0 ± 9.3 (range, 20-65). One or more FNAB was performed in 23 of the patients (16.8%) at the beginning and/or during the follow-up period when needed. Seven patients with suspicious FNAB findings were operated, and histopathological examination of the nodules confirmed the diagnosis of papillary thyroid carcinoma in 6 patients (4.4%). Conclusions Our observations suggesting a relatively higher prevalence of thyroid cancer in a small series of SAT patients warrant further studies to identify the real frequency of differentiated thyroid cancer and its association with inflammatory pathogenesis of SAT. This finding is compatible with the trend of increased thyroid cancer incidence all over the world. A repeat ultrasonography after resolution of clinical and inflammatory findings, and FNAB should be recommended to all patients with suspicious nodules.

DID CHERNOBYL ACCIDENT CONTRIBUTE TO THE RISE OF THYROID CANCER IN TURKEY?

Context

Radioactivity has been known to be a causative factor for thyroid cancer.

Objective

To answer whether the Chernobyl nuclear accident had any harmful effect on the rate of thyroid cancers after a wait-and-see period.

Background

The Chernobyl accident in 1986 was chosen as a milestone because of its close proximity to the geographical area studied.

Design

The time periods chosen were: I. 1990-1996 (latent period), II. 1997-2003 (sensitive period), III. 2004-2015 (control period).

Subject and Methods

A retrospective study was conducted in a teaching and reference state hospital. The statistical analysis of the data of 4251 patients was made by chi-square and Fisher exact tests.

Results

A total of 4251 patients were operated on because of thyroid diseases between 1990-2015. The number of patients in regard to the three time periods were 817, 1141 and 2293, respectively. Statistically significant rise of thyroid cancer and significant geographic vulnerability among different parts of the country were detected between the first two periods, but not between the second and third. The rising rates of malignancy were 1.71% (14/817), 6.83% (78/1141) and 8.59%(197/2293). The mean ages of malignant cases were 51.07 years, 46.2 years and 41.8 years although the mean ages of benign cases were 47.91,60.2, and 61.3 years according to groups, respectively.

Conclusion

The Chernobyl nuclear accident seemed to have harmful effect on the rate of thyroid cancer or at least contributed to its increase.

The rising trend of papillary carcinoma in thyroidectomies: 14-years of experience in a referral center of Turkey

Background

During the past 25 years, the incidence of thyroid papillary carcinoma (TPC), especially the micropapillary subtype, has been increasing in different countries worldwide. The rise in the rate of thyroid malignancies were also determined in Turkey in the last two decades. This fact was attributed to the Chernobyl accident because Turkey is one of the affected countries by the radioactive fallout. The aim of this study was to assess the changes in the parameters of the thyroid and put forth the reasons in a 14-year period.

Methods

The patient records, demographic and malignancy characteristics, and operations of 1,585 patients who had a thyroidectomy from 1996 to 2009 were reviewed retrospectively. The study was divided in two equal time periods for comparison of data.

Results

A total of 216 thyroid carcinomas (13.6%) were diagnosed in the study period. There was a significant increase in the frequency of papillary (P <0.023) and micropapillary (P <0.001) carcinomas when the two different time periods were compared. The rate of follicular, medullary and other types of malignancies did not change. In the second period (2003 to 2009) of analysis, the rate of micropapillary carcinoma (P = 0.001) and within male (P = 0.031) and female (P <0.001) genders, application of total thyroidectomy (p = 0.029), and multicentric disease (P = 0.015) increased significantly. A slight decrease in the mean age of the whole number of patients and patients with papillary and micropapillary carcinomas (P >0.05) was observed. The increased number of TPC >10 mm was insignificant. Geographic region and age specific malignancy increase was not determined.

Conclusions

Micropapillary carcinoma has become a dominant type of thyroid malignancy in Turkey. The main reasons of this transition were mandatory iodization and much higher application of total thyroidectomy in surgery. Improvement in healthcare and diagnostic techniques are the complementary factors. Due to its lack of molecular and genetic basis from the perspective of thyroid cancer, the Chernobyl disaster has lost its importance in Turkey.

Distribution of Thyroid Cancer in the Eastern Part of Turkey 27 Years After the Chernobyl Accident

Background

The Chernobyl accident caused widespread effects across Europe and huge areas where radiocontaminated. The effects of the Chernobyl accident on thyroid cancer have been investigated in most European countries. According to the data of the Turkish Atomic Energy Authority, the eastern part of the Black Sea region was the most radiocontaminated area in Turkey at the time of Chernobyl accident. We therefore aimed to examine the data of thyroid cancers at our center, Rize city which is located in the eastern Black Sea region.

Methods

This retrospective study included the patients with histologically proven thyroid cancer at our center between January 2008 and May 2012. Pathologic examinations of thyroidectomy materials were reviewed. We evaluated patients’ age, gender, size of the primary tumor (all sizes, < 1 cm, 1 - 2.9 cm, 3 - 3.9 cm and ≥ 4 cm), multicentricity, histologic subtypes of thyroid cancer, the presence of lymphatic, vascular, capsule and the extrathyroidal invasion.

Results

Five hundred and forty-seven of the 3,556 patients were diagnosed with thyroid cancer. The mean age of the patients was 49.31 ± 0.49 years. The histopathologic diagnosis of patients was papillary carcinoma in 533 (97.4%) and the tumor size was < 1 cm in 53.6% of the patients. The presence of multicentricity was detected in 47% of the patients.

Conclusion

The portion of thyroid carcinomas in all thyroidectomies was 15.4% in our institution 27 years after the Chernobyl accident.

Thyroid cancer in pediatric age group: an institutional experience and review of the literature

Very few have been reported on children with differentiated thyroid cancer (DTC), although 15% of them are diagnosed below 20 years of age. Children with DTC present with more advanced disease; however, they have a more favorable outcome. In this paper, we aimed to present the data in our institution on pediatric DTC patients, making an emphasis on the risk factors of metastasis and recurrence, as well as to the outcome of treatment. Clinical data of 50 pediatric patients referred to our institution for radioiodine treatment (RAI) between 1976 and 2010 were obtained. Papillary carcinoma was the most common histopathologic diagnosis (36 patients) followed by papillary carcinoma with follicular variant (10 patients). Multifocality was reported in 66% of the pathology reports. At the time of diagnosis 35 patients had regional lymph node metastasis, 18 had local invasion, and 11 had distant metastasis. No distant metastasis was present in patients with unifocal disease (P=0.018). The mean duration of follow-up was 77.6±62.7 months. Patients with local disease had longer disease-free survival than patients with distant metastasis (P=0.033). Despite the small number of patients, the follow-up was relatively long and the presented results confirmed overall good prognosis in children with DTC.

Effects of the chernobyl disaster on thyroid cancer incidence in Turkey after 22 years

Background. Separate studies involving people who survived atomic bombs have shown that the risk for cancer remains high after 40 years, compared with the risk in the general population. An elevated risk may also remain in regions of Turkey near the Chernobyl disaster. Patients and Methods. A multidisciplinary study conducted in 2008, 22 years after the Chernobyl disaster, examined the thyroid cancer incidence in Rize, a province of Turkey located on the shore of the middle Black Sea. Approximately 100,000 people were screened, and a fine-needle aspiration biopsy was performed in 89 patients. Results. Based on postoperative histopathological examinations, thyroid cancer was diagnosed in six of the 100,000 people screened. Conclusion. Given a thyroid cancer frequency of approximately 8 in 100,000 in the Turkish population, according to the Turkish Cancer Research Association, the rate in Rize reflects no increase in the thyroid cancer incidence 22 years after the Chernobyl disaster.

Differences in the Form of Presentation between Papillary Microcarcinomas and Papillary Carcinomas of Larger Size

Papillary thyroid carcinomas (PTCs) with a diameter ≤1 cm are referred to as papillary microcarcinomas (PTMCs). The prognostic factors for PTMCs have not been defined. Different clinical and histopathologic variables were studied in 152 PTCs, including 74 PTMCs and 78 PTCs of larger size. We found that PTMCs are associated with less multifocality (P = .046) and bilaterality (P = .003), fewer lymphadenectomies (P < .001), and a higher rate of incidental tumours (P < .001). Moreover, patients with a low aggressive profile were significantly older than the remaining patients (54 ± 13.7 years versus 45.8 ± 13.1 years; P = .001). In conclusion PTMCs show significant differences compared to PTCs of larger size in the form of presentation. Furthermore, it is possible that the classic risk factors, which are well validated in PTCs, such as age, must be cautiously interpreted in the current increasing subgroup of PTMCs.

Increasing prevalence of papillary thyroid carcinoma in recent years in Greece: the majority are incidental

BACKGROUND

New cases of well-differentiated thyroid cancer (DTC) are diagnosed more frequently worldwide. We investigated trends and differences in clinical and histological characteristics of new DTC cases presenting in one large center.

METHODS

During the last 34 years 852 follicular cell-derived DTC cases (83% papillary [PTC], 17% follicular [FTC] carcinoma) presented in the Endocrine Unit of the Department of Clinical Therapeutics in Alexandra Hospital (18.8% men, mean age 42.4 +/- 14.5 years). Patients were classified in three period groups according to year of diagnosis: period 1, 1963-1982; period 2, 1983-1992; and period 3, 1993-2007. We recorded the histological type, age at diagnosis, and, in period 3, the type of pre-existing thyroid disease, the stage, and tumor size.

RESULTS

During periods 1, 2, and 3, the mean age at diagnosis was 37.7 +/- 12.3, 42.4 +/- 14.53, and 44.1 +/- 14.9 years (p = 0.001), respectively, and the male to female ratio was similar. The prevalence of FTC was 22.7%, 28.1%, and 6.5%, respectively. In period 3, 51.6% of the PTCs were microcarcinomas (microPTC) <or=10 mm; these patients tended to be older (p = 0.09). Microcarcinomas were more frequent among patients operated for pre-existing multinodular goiter (MNG) or prominent hot nodule compared to pre-existing single cold nodule (p < 0.001, Pearson chi(2)). In period 3, 88% of the microPTC diagnoses were incidental. Of the incidental microPTCs detected in MNG, 25% had capsular invasion, 4.5% had lymph node involvement, and 3.6% had soft tissue involvement.

CONCLUSIONS

We hypothesize that the prevalence of FTC during the last decade in our center in Greece was very low due to correction of iodine deficiency and a relative increase in the prevalence of microPTC. More than 50% of PTC diagnosed during the last decade were microPTCs that were detected incidentally in older persons with preexisting MNG or a prominent hot nodule. This is one of the highest, if not the highest percentage of microPTCs that were incidentally detected. Despite many of these having features of invasiveness, most appear to remain clinically silent. Research is needed to identify factors predisposing microPTCs to evolve from a subclinical to a clinically apparent form.