Am J Surg. Increasing incidence of differentiated thyroid cancer in the United States, Rising thyroid cancer incidence in the United States by demographic and tumor characteristics, Cancer Epidemiol Biomarkers Prev.
Thyroid cancer incidence patterns in the United States by histologic type, The prevalence and significance of incidental thyroid nodules identified on computed tomography.
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J Clin Endocrinol Metab. Risk of malignancy in thyroid incidentalomas identified by fluorodeoxyglucose—positron emission tomography. Evaluation and management of incidentally discovered thyroid nodules.
Surg Oncol. Incidental vs clinically evident thyroid cancer: a 5-year follow-up study. Head Neck. Google Scholar Crossref. Thyroid papillary cancers: microcarcinoma and carcinoma, incidental cancers and non-incidental cancers—are they different diseases? Clin Endocrinol Oxf. Natural history and clinical outcome of differentiated thyroid carcinoma: a retrospective analysis of patients treated at a single institution.
Ann Oncol. Prognostic indicators in differentiated thyroid carcinoma. Cancer Control. PubMed Google Scholar. Thyroid cancer gender disparity. Future Oncol. Owens GM. Gender differences in health care expenditures, resource utilization, and quality of care. J Manag Care Pharm. Int J Endocrinol. Pathways to the diagnosis of thyroid cancer in New South Wales: a population-based cross-sectional study. Cancer Causes Control. The increasing incidence of small thyroid cancers: where are the cases coming from?
Bhargavan M, Sunshine JH. Utilization of radiology services in the United States: levels and trends in modalities, regions, and populations. Save Preferences. Privacy Policy Terms of Use. This Issue. Views 3, Citations View Metrics.
Twitter Facebook More LinkedIn. Original Investigation. November Hershey Medical Center, Hershey. Back to top Article Information. In the case of iodine deficiency, the thyroid uptake of radioactive iodine is high, resulting in high radiation doses to the thyroid gland.
Iodine deficiency may also increase the proliferation rate of thyroid cells that may facilitate the occurrence of thyroid cancers, and this may have occurred in contaminated children in Belarus, Ukraine, and Russia 17 Morphologic characteristics of Chernobyl-related childhood papillary thyroid carcinomas are independent of radiation exposure but vary with iodine intake.
In a cohort of 4, 5-year survivors of solid childhood cancer, the thyroid cancer risk increased after splenectomy and decreased after high radiation doses to the pituitary gland. The authors hypothesized that after splenectomy, the immunological alterations could be involved in the development of thyroid carcinoma and that, after pituitary irradiation, low serum TSH levels will result in lower thyroid stimulation 12 Until recently, chemotherapy administration was not considered to be a risk factor for thyroid carcinoma after radiation therapy for a childhood cancer or as a potential radiation dose response-modifier 5 5.
However, it is currently considered that chemotherapy during childhood increases the risk of subsequent thyroid carcinoma by 4 folds if given alone and that the risk of chemotherapy is additive to the risk of radiation therapy when both are given 19 The risk of thyroid carcinoma per unit of radiation dose to the thyroid was higher in subjects with a body mass index BMI higher than 25 or a larger BSA body surface area 12 These data show that the risk for any radiation dose to the thyroid gland may be modified by many factors, but as already stated, screening biases should always be kept in mind.
Several other thyroid abnormalities may be caused by radiation exposure 28 Exposing the thyroid to radiation: a review of its current extent, risks, and implications. Endocr Rev. The risk of hypothyroidism, probably as a consequence of cellular death, increases with the radiation dose.
In a study of 4, Hiroshima and Nagasaki survivors, autoimmune thyroid diseases were not associated with radiation exposure 29 Radiation dose-response relationships for thyroid nodules and autoimmune thyroid diseases in Hiroshima and Nagasaki atomic bomb survivors years after radiation exposure.
Finally, several studies have indicated that low-doses of radiation to the thyroid could be associated with an increased prevalence of anti-thyroid antibodies 30 Autoimmune thyroid disease associated with environmental thyroidal irradiation. A familial susceptibility to radiation-induced thyroid cancer has been suggested by the pedigree of some families in which several irradiated individuals have developed a thyroid tumor more often that would be expected by chance.
Also, the association of thyroid, parathyroid, salivary gland, or neural tumors in a subject exposed to radiation to the neck suggests a predisposition to develop tumors after radiation exposure. However, the natural history of the thyroid cancer was not altered by any familial concordance 31 Familial concordance of thyroid and other head and neck tumors in an irradiated cohort: analysis of contributing factors. PTC is the most frequent form of thyroid carcinoma diagnosed after radiation exposure.
After the Chernobyl accident, most young children had a solid or follicular PTC subtype with an aggressive behavior and a short latency period, whereas older children had more frequently classical PTC that was less aggressive and was discovered after a longer latency period. Solid subtype was also frequently observed in the rare PTC that occurred in young children in the absence of any radiation exposure, demonstrating that this subtype is associated with a younger age at occurrence of the tumor 16 Differentiated thyroid carcinoma in childhood: long term follow-up of 72 patients.
Radiation exposure increases DUOX1 expression, leading to an important production of ROS in the thyroid gland after radiation exposure, and this may explain its high sensitivity to radiation 33 This DNA damage includes single- or double-strand breaks that will result in deletions and chromosomal rearrangements.
Normal thyrocytes multiply during body growth, especially before the age of 5 years, and this will favor the accumulation of genetic defects after radiation exposure.
Mitotic rate decreases with age and becomes very low in adults. This may explain the high sensitivity of the thyroid gland to the carcinogenic effects of radiation at birth, which decreases with increasing age, becoming low or not significant after the age of years 5 5.
In PTC occurring after radiation exposure, intra-chromosomal rearrangements are frequently observed. Pattern of ras and gsp oncogene mutations in radiation-associated human thyroid tumors.
Identification of kinase fusion oncogenes in post-Chernobyl radiation-induced thyroid cancers. J Clin Invest. Pattern of radiation-induced RET and NTRK1 rearrangements in post-Chernobyl papillary thyroid carcinomas: biological, phenotypic, and clinical implications. Clin Cancer Res. Oncogenic rearrangements of the RET proto-oncogene in papillary thyroid carcinomas from children exposed to the Chernobyl nuclear accident.
Cancer Res. Activated RET oncogene in thyroid cancers of children from areas contaminated by Chernobyl accident. High prevalence of RET rearrangement in thyroid tumors of children from Belarus after the Chernobyl reactor accident. Oncogenic alterations in papillary thyroid cancers of young patients. A transcriptomic signature that includes genes that are differently expressed in sporadic tumors relative to tumors occurring after external radiation exposure during childhood permits the distinction of these two groups of tumors with a sensitivity of 0.
Gene expression signature discriminates sporadic from post-radiotherapy-induced thyroid tumors. Endocr Relat Cancer.
Furthermore, this signature allows for classifying tumors from Belarus and Ukraine as either sporadic or occurring in highly contaminated subjects during the Chernobyl accident 43 Discriminating gene expression signature of radiation-induced thyroid tumors after either external exposure or internal contamination.
These data confirm previous studies 44 A radiation-induced gene signature distinguishes post-Chernobyl from sporadic papillary thyroid cancers. Copy number and gene expression alterations in radiation-induced papillary thyroid carcinoma from Chernobyl pediatric patients.
Radiation signatures in childhood thyroid cancers after the Chernobyl accident: possible roles of radiation in carcinogenesis. Cancer Sci. Strategy to find molecular signatures in a small series of rare cancers: validation for radiation-induced breast and thyroid tumors. PloS One. The risk of developing a thyroid cancer and its temporal pattern of occurrence is of clinical importance for the long-term surveillance of late effects of radiation to the neck.
In daily practice, the clinician could be in front of patients who have been exposed to external radiation or patients with thyroid abnormalities that require the search for a history of radiation exposure 28 In the case of external radiation exposure, the risk of radiation-induced thyroid tumor can be estimated according to the age at exposure and the dose delivered to the thyroid gland; additionally, it is important to search for other effects of radiation and a personal or family history of head and neck tumors.
An exhaustive physical examination and ultrasonography of the thyroid gland and of lymph node areas are performed. Also abnormalities that may be induced by radiation exposure to the neck such as tumors of the salivary glands, hyperparathyroidism, and neural tumors should be screened. Laboratory tests include screening for hypothyroidism TSH and hyperparathyroidism calcium. Radiation exposure during childhood increases the risk of hyperparathyroidism, and this risk increases with radiation doses 48 Levels of parathyroid hormone and calcitonin in serum among atomic bomb survivors.
Hyperparathyroidism after radioactive iodine therapy. Am J Surg. Subjects exposed to radiation with high Tg levels and with a normal clinical examination have an increased risk of developing thyroid nodules 50 Thyroid nodules in the follow-up of irradiated individuals: comparison of thyroid ultrasound with scanning and palpation.
Patients with a history of radiation exposure during childhood Figure 1 should be submitted to follow-up for life. Patients without abnormalities can be evaluated every 1 to 5 years, according to risk factors. Figure 1 Work-up of subjects with a history of external radiation during childhood.
Solid thyroid nodules larger than 1 cm in diameter are submitted to fine needle biopsy for cytology. If multiple nodules are found, the fine needle biopsy is indicated in nodules that are suspicious at ultrasound.
Patients with sub-centimeter nodules are controlled every years with ultrasonography. Hypothyroidism is treated with levothyroxine. In addition, levothyroxine treatment is considered in euthyroid patients with high risk factors and in patients with small nodules in order to maintain the serum TSH levels in the low normal range. If the cytology suggests the presence of a papillary carcinoma, a total thyroidectomy is recommended.
Total thyroidectomy is also performed when surgery has been decided for an apparently benign nodule, with the aim of reducing the risk of nodule recurrence. Evaluation of the consequences of the Chernobyl accident has clearly demonstrated that contamination with radioactive isotopes of iodine during childhood increases the risk of developing a thyroid cancer.
Follicular cells. These cells are responsible for the production of thyroid hormone. Thyroid hormone is needed to live. The hormone controls the basic metabolism of the body. It controls how quickly calories are burned.
This can affect weight loss and weight gain, slow down or speed up the heartbeat, raise or lower body temperature, influence how quickly food moves through the digestive tract, control the way muscles contract, and control how quickly dying cells are replaced. C cells. These special cells of the thyroid make calcitonin, a hormone that participates in calcium metabolism.
A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread. Papillary thyroid cancer. Papillary thyroid cancer develops from follicular cells and usually grow slowly. It is the most common type of thyroid cancer. It is usually found in 1 lobe. It is a differentiated thyroid cancer, meaning that the tumor looks similar to normal thyroid tissue under a microscope.
Papillary thyroid cancer can often spread to lymph nodes. Follicular thyroid cancer. Follicular thyroid cancer also develops from follicular cells and usually grows slowly. Follicular thyroid cancer is also a differentiated thyroid cancer, but it is far less common than papillary thyroid cancer. Follicular thyroid cancer rarely spreads to lymph nodes. Follicular thyroid cancer and papillary thyroid cancer are the most common differentiated thyroid cancers.
They are very often curable, especially when found early and in people younger than Hurthle cell cancer. Hurthle cell cancer, also called Hurthle cell carcinoma, is cancer that is arises from a certain type of follicular cell.
Hurthle cell cancers are much more likely to spread to lymph nodes than other follicular thyroid cancers. Medullary thyroid cancer MTC.
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