The Chernobyl nuclear power plant accident happened on April 26, 1986. We investigated the cause of the striking increase in frequency of thyroid cancer in children who lived within a 150 km radius of Chernobyl and who were born before and after the accident. No thyroid cancer was seen in 9472 children born in 1987-89, whereas one and 31 thyroid cancers were recorded in 2409 children born April 27, 1986, to Dec 31, 1986, and 9720 born Jan 1, 1983, to April 26, 1986, respectively. Short-lived radioactive fallout caused by the Chernobyl accident probably induced thyroid cancer in children living near Chernobyl.
Health effects as a result of the accident at the Chernobyl nuclear power plant occurred in 1986 are considered in the paper. Wrong prognosis of the health effects with respect to mortality and morbidity among the population exposed to low radiation doses is shown. Proven increase in thyroid cancer cases among people who were children aged from 0 to 18 at the time of the accident is shown. Linear relationship between thyroid cancer cases and dose to thyroid ranged from 0.2 to 4.0 Gy is considered. An additional absolute risk of thyroid cancer in children varies in the range 1.9-2.6 cases per 10(4) person-year Gy. During the fifteen years following the accident no cases of acute and chronic radiation sickness have been revealed because the population living in contaminated areas received low radiation doses. Also, exposures to low radiation doses did not result in excess of malignant tumors among population. In some cases the outcomes of acute radiation sickness were as follows: radiation damages to the skin, cancer cataracts, development of oncopathology.
Heterotrimeric G proteins participate in the signal transduction cascade. Adult thyroid tumors have been shown to harbor specific point mutations in codons 201 and 227 of the G(s)alpha subunit of the adenylate cyclase stimulator. This protein affects the GDP/GTP turnover and finally results in an enhanced activation of G(s) and thus adenylate cyclase. We attempted to find out if G(s)alpha gene mutations were present in thyroid tumors of children from Belarus after the Chernobyl nuclear accident. Paraffin sections of 20 thyroid tumors were used for PCR amplification by oligonucleotide intron primers flanking exons 8 and 9, encompassing codon 201 and 227, respectively. By direct sequencing of the 274-bp amplification product, we did not detect any mutations of the G(s)alpha gene in codon 201 or 227. In contrast to thyroid neoplasia of adults, G(s)alpha gene mutations do not play a role in the development of childhood thyroid tumors after the Chernobyl reactor accident.
OBJECTIVE: Several studies have suggested that patients with acromegaly have an increased risk of benign and malignant neoplasms, especially of the colon. To further investigate this relationship we evaluated cancer risk in population-based cohorts of acromegaly patients in Sweden and Denmark. METHODS: Nationwide registry-based cohorts of patients hospitalized for acromegaly (Denmark 1977-1993; Sweden 1965-1993) were linked to tumor registry data for up to 15-28 years of follow-up, respectively. Standardized incidence ratios (SIR) and 95% confidence intervals (CI) were calculated to estimate cancer risk among 1634 patients with acromegaly. RESULTS: The patterns of cancer risk in Sweden and Denmark were similar. After excluding the first year of follow-up, 177 patients with acromegaly had a diagnosis of cancer compared with an expected number of 116.5 (SIR = 1.5. 95% CI = 1.3-1.8). Increased risks were found for digestive system cancers (SIR = 2.1, 95% CI = 1.62.7), notably of the small intestine (SIR = 6.0, 95% CI = 1.2-17.4), colon (SIR = 2.6, 95% CI = 1.6-3.8), and rectum (SIR = 2.5, 95% CI= 1.3-4.2). Risks were also elevated for cancers of the brain (SIR = 2.7, 95% CI= 1.2-5.0). thyroid (SIR = 3.7, 95% CI = 1.8-10.9), kidney (SIR = 3.2, 95% CI = 1.6-5.5), and bone (SIR= 13.8, 95% CI= 1.7-50.0). CONCLUSIONS: The increased risk for several cancer sites among acromegaly patients may be due to the elevated proliferative and anti-apoptotic activity associated with increased circulating levels of insulin-like growth factor-1 (IGF-1). Pituitary irradiation given to some patients may have contributed to the excess risks of brain tumors and thyroid cancer. Our findings indicate the need for close medical surveillance of patients with acromegaly, and further studies of the IGF-I system in the etiology of various cancers.
The concept of a thyroid disease register based on a relational database system with a structured query language (SQL) is reported. More than 5000 examination findings of benign and malignant thyroid disorders have been recorded so far, covering the period from 1986 to 1996. For epidemiological studies these population-based thyroid diseases data can be allocated to a digital data map by means of the five-digit German postal code. When evaluating the data with regard to the function of the thyroid gland as an indicator of preceding nuclear power plant disasters and fallout, we found neither indicators of an increased incidence of thyroid carcinoma as an aftermath of the Chernobyl disaster nor the occurrence of clusters. The data were supplemented by the results of a survey among all Schleswig-Holstein pathologists involved in the diagnosis of thyroid diseases. Data on childhood carcinoma of the thyroid were also provided by the Childhood Tumor Register of the Institute of Pathology, University of Kiel, and by the Childhood Cancer Register of the University of Mainz.
Beginning approximately 4 years after the Chernobyl nuclear accident a steady increase in the incidence of thyroid cancer was observed in children and adolescents of the Bryansk Oblast, which received the highest level of radionuclide contaminants in Russia. We examined the spatial relationship between the residence location of patients with identified thyroid cancer (0-18 years old at the time of the accident) and a number of geographic parameters to better account for the etiology of thyroid cancer spatial distribution. Geographic parameters analyzed included spatial distribution of 137Cs and 131I in soil, population demographics, measurements and reconstructions. of absorbed thyroid 131I doses in the population, and maps of major transportation arteries. An interesting finding is the lack of a consistent correlation between the spatial distribution of radionuclides in the soil and thyroid cancer incidence. Instead, most of the thyroid cancer cases were diagnosed in settlements situated on major railways and roads. Correlating population with thyroid cancer cases and transportation arteries reveals a much higher cancer rate on or near major roads and railways than at a distance from them, again independent of radionuclide soil concentration. There are other important factors, of course, that must be considered in future evaluations of this phenomenon. These include the influence of iodine endemic zones, genetic predisposition to thyroid cancer, and duration of residence time in contaminated areas. The feasibility of radionuclide transport on railways and roads is discussed, together with the vectors for transfer of the contaminants to the human population. Developing a model to reconstruct the radiation dose to the thyroid over time in this geographic region is proposed in light of the impact of transportation arteries. Specific studies are outlined to provide the data necessary to develop this model as well as to better characterize the feasibility and scientific validity of the contribution to human health effects of this transport factor. Transport factor refers to the transport of radionuclides on transportation arteries and the transfer of these agents to the human population residing in the vicinity of these arteries. If the impact on thyroid cancer of the transport of radionuclides on major railways and roads is indeed significant, a major reappraisal of the risk of large-scale radioactive release into the environment is necessary.
We investigated cancer risk among mothers of 2365 children who were diagnosed with cancer between 1973 and 1989 in Sweden. From the date of birth of the child until 31 December 1989, 38 cases of cancer were diagnosed among the mothers. The expected number of cases, according to national rates, was 30.9. Cancer of the thyroid was the only site showing a significantly increased risk among the mothers (observed = 6, expected = 1.2, P
Thyroid cancer is a relatively rare cancer (5 new cases/y/10(5) inhabitants). An excess of thyroid carcinoma has been found in some but not in all goiter endemic areas. Follicular and anaplastic carcinomas have been found particularly frequent in regions of goitre endemia. A significant increase of thyroid carcinoma has also been found in iodine sufficient areas (Norway, Iceland, Hawaii). In several surveys a positive correlation has been found between parity and incidence of differentiated thyroid carcinoma. Natural goitrogens and chemotherapeutic agents have been proved to induce hyperplasia but their role in carcinogenesis of exposed populations is not yet definitely ascertained. Exposure to external radiation is carcinogenic for the thyroid both in human and in experimental animals. Patients treated for hyperthyroidism or thyroid cancer or given diagnostic doses of 131-I (0.5 Gy/test) indicate that under these conditions 131-I is not carcinogenic. Findings on population exposed to radioactive fallout showed an increased incidence of thyroid carcinomas compared to unexposed populations. After the Chernobyl accident (1986) particular attention was given to calculate the risk of thyroid cancer caused by the fallout of 131-I. Up to now a considerable increase of thyroid carcinoma has been reported in children of a region near Chernobyl (Belarus).