Histological Types Of Thyroid Cancer Research Articles

Iodine supplementation in Austria: methods and results.

Until 1963 Austria was an extremely iodine-deficient area with low iodine intake and high goiter prevalence. Therefore, for the first time in 1963, salt iodination with 10 mg of potassium iodide per kilogram of salt was introduced by federal law. Twenty years after this salt iodination, however, investigations in schoolchildren demonstrated iodine deficiency grade I to II according to the World Health Organization (WHO) (urinary iodine excretion, 42-75 microg/g Crea) and goiter prevalence of far more than 10%. In 1990, salt iodination was increased to 20 mg of potassium iodide per kilogram of salt. In 1994, further investigations in schoolchildren demonstrated an increase of urinary iodine excretion (121 microg/g Crea) and a reduction of goiter prevalence below 5%, with the exception of pupils ages 14-19 (12%). In the year 2000, 10 years after the increase of salt iodination in Austria, 430 nonselected adult inhabitants of three communities in Carinthia (a county of Austria) were investigated for iodine excretion, goiter prevalence, and prevalence of thyroid autoantibodies. This study demonstrated that although iodine supply is sufficient now in Austria (males, 163.7 microg of Crea; females, 183.3 microg of iodine per gram of Crea), goiter prevalence is still high in the elderly, who lived for a longer period of iodine deficiency (34.3% in women and 21.3% in men), whereas goiter prevalence in younger people up to age 40 years is below 5%. It could also be shown that the percentage of thyroid autoantibodies is now as high as in other countries with sufficient iodine supply (3.19% in males, 5.17% in females). In addition to the changes of urinary iodine excretion and goiter prevalence because of salt iodination, changes of incidence in hyperthyroidism and histologic types of thyroid cancer are discussed in this paper. In conclusion, the introduction of salt iodination led to an improvement in iodine supply with a marked reduction of goiter prevalence in people who were born after 1963, but also to an increase in hyperthyroidism and autoimmune thyroid diseases as well as changes in histologic types of thyroid cancer.

Radiotherapy planning techniques for thyroid cancer.

External beam radiotherapy has a role in each histological type of thyroid cancer. For treatment confined to the thyroid bed, an antero--oblique wedged pair of beams is simple to apply. More frequently, however, the volume needs to include both sides of the neck and adequate dose must be given down to the level of the suprasternal notch, precluding use of lateral fields. Thus, anterior and posterior fields are usually necessary, extending from the tips of the mastoid processes or hyoid down to the carina and laterally to include both sides of the neck and supraclavicular fossae. The mandible and infraclavicular portions of both lungs are shielded, but there is no midline lead in the phase one volume. A mid-plane dose of 46 Gy given in 23 daily fractions results in an acceptable early radiation reaction and will avoid late damage to the spinal cord. Because of considerable variation of interplanar distance along the length of the volume, a lateral simulator film should be taken to determine the maximum cord dose. For most patients, a three-dimensional CT planned phase two volume will be required and should be determined prior to completing phase one. The optimum beam arrangement, usually incorporating conformal beam shaping assisted by use of a multileaf collimator, should avoid further dose to the cord. If there is additional dose to the spinal cord, this phase can be introduced before 46 Gy is reached.

Is residence in areas of endemic goiter a risk factor for thyroid cancer?

The association between an indicator of iodine deficiency and differentiated thyroid cancer has been investigated in a population-based case-control study. This included all incident cases (N = 484) of papillary and follicular thyroid cancer diagnosed during the years 1980-1992 in a Swedish Health Care Region among residents born in Sweden, and as many individually matched controls. Cases were included after a uniform review of their histopathological specimens. Residence in areas where goiter had been severely endemic in the 1930s was used as exposure indicator. Odds ratios (OR) and 95% confidence intervals as estimates of relative risk were calculated as a measure of association using logistic regression. A trend toward an association was found with a duration of residence in goiter areas between 21 and 40 years, most prominent among follicular cancer cases and in the group diagnosed at age > or = 50 years compared to not exposed. Exposure for the first time during adolescence (between 11 and 20 years) was associated with an increased risk of papillary cancer. This was especially evident among women, both when compared to not exposed and to those exposed during the first year of life; the association was strengthened after adjustment for duration of residence. These findings support the hypothesis of distinct causation patterns from iodine deficiency to the 2 most common histological types of thyroid cancer.

Endocrine gland cancer

Incidence and prognosis of cancers of the endocrine glands vary greatly by histologic type. Population-based data from SEER registries, 1973-1987, were analyzed. Thyroid cancer accounts for most (92%) of the cancers of the endocrine glands. The four major histologic types of thyroid cancer display distinct patterns, reflecting different biologic entities. Papillary carcinoma, the most common type, occurs more frequently in women than in men and in whites than in blacks and has an early onset. Follicular carcinoma, the second most common type, shows a steady increase in incidence with age and a female preponderance but no racial disparity. Medullary carcinoma, the rare differentiated thyroid tumor, has a female excess in whites only and a slow increase in incidence with age. Anaplastic carcinoma shows few racial or sex variations and reaches a substantial level only after age 50. The prognosis also varies greatly by histologic type. The overall 5-year relative survival rate is greater than 90% for papillary and follicular carcinomas, 82% for medullary carcinoma, and less than 10% for anaplastic carcinoma. Carcinomas of the suprarenal gland and thymus are rare, accounting for about 3% of endocrine cancers each. These tumors, unlike the differentiated thyroid cancer, show no female preponderance, have a higher incidence rate in blacks, and have a poorer survival rate. The marked predominance of papillary carcinoma and the continued increase in its relative frequency characterize the postgoiter era and an increased use of scintigraphy and fine needle aspiration. Underdiagnosis of small tumors may explain the observed lower incidence of papillary carcinoma in blacks.

Immunohistochemical analysis of amylase isoenzymes in thyroid cancer.

The expression of amylase in various histological types of thyroid cancer was studied by an immunohistochemical technique, using a polyclonal antiamylase antiserum and two monoclonal antibodies specific for salivary and pancreatic-type amylases, respectively. Amylase was expressed in 21 of 24 (88%) thyroid cancers by polyclonal antiserum analysis. Analysis by monoclonal antibodies, however, showed that only 13 (54%) cases and three (13%) cases contained salivary-type and pancreatic-type amylases, respectively. Moreover, immunoreactivity for pancreatic-type amylase was detected only in medullary carcinoma; other histological types were positive for salivary-type amylase. These results show that thyroid cancer frequently expresses amylase, and suggest that the differences between amylase isoenzymes in thyroid cancer may correlate with those found between cellular origin of tumour.

Thyroid and Parathyroid Cancer

The epidemiology, etiology, pathology, and management of thyroid and parathyroid carcinoma are discussed. Emphasis is placed on the clinical differences in the management and treatment of the various histologic subtypes of thyroid cancer. The biologic and prognostic differences among the various histologic types of thyroid cancer and their relationship to age are stressed.

Histological types of thyroid cancer in hong kong chinese, 1986-1988

This study aims at comparing the histological, age and sex distribution of thyroid cancer in the Hong Kong Chinese with a similar study undertaken 13 years ago. Ninety consecutive cases from 1986 to 1988 were reviewed. Only cases diagnosed by biopsy or surgical excision were included. Autopsy cases and incidental occult papillary carcinoma were excluded. The revised WHO classification was used. 72.5% were papillary carcinoma, 23.1% follicular carcinoma, 1.1% undifferentiated carcinoma, 2.2% medullary carcinoma. The overall male:female (M:F) ratio was 1:3.5. Compared to the previous study, the proportion of papillary carcinoma was altered from 59.8% to 72.5%, that of follicular carcinoma from 21.3% to 23.1%, that of undifferentiated carcinoma from 16.4% to 1.1%. Although the overall M:F ratio was similar (1:3.1 versus 1:3.5), in papillary carcinoma, the M:F ratio was altered from 1:2.8 to 1:4.7; and in follicular carcinomas from 1:5.5 to 1:2.0. There was also a shift in age incidence of follicular carcinoma in males to the older age groups. While the changes in histological types might be due to changes in classification, the changes in sex ratio and age distribution were probably genuine. These changing patterns might help to determine the aetiology of thyroid cancer.

Thyroid and Parathyroid Cancer

The epidemiology, etiology, pathology, and management of thyroid and parathyroid carcinoma are discussed. Emphasis is placed on the clinical differences in the management and treatment of the various histologic subtypes of thyroid cancer. The biologic and prognostic differences among the various histologic types of thyroid cancer and their relationship to age are stressed.

The relation of susceptibility to and biologic behavior of thyroid epithelial cell cancer to HLA-DR1.

Fifty-two patients with thyroid epithelial cell cancer were studied for evidence of association with human leukocyte antigens (HLA). Twenty-eight patients (53.8%) and 19.4% of 160 controls were HLA-DR1-positive, conferring a relative risk of 4.85 (chi 2 = 21.3, P less than 0.0001). HLA-DR1 was increased in all histologic types of thyroid cancer. Interestingly 10 of 12 patients with metastatic disease were DR1-positive compared to 18 of 41 patients without metastases (relative risk = 6.1, chi 2 = 4.7, P less than 0.05). This study suggests that major histocompatibility complex-linked gene(s) determine susceptibility to and the biologic behavior of thyroid cancer.