Autoimmune thyroiditis and exposure to iodine 131 in the Ukrainian cohort study of thyroid cancer and other thyroid diseases after the Chornobyl accident: results from the first screening cycle (1998-2000).

CONTEXT: Due to the Chornobyl accident, millions were exposed to radioactive isotopes of iodine and some received appreciable iodine 131 (131I) doses. A subsequent increase in thyroid cancer has been largely attributed to this exposure, but evidence concerning autoimmune thyroiditis (AIT) remains inconclusive. OBJECTIVE: The objective of the study was to quantify risk of AIT after 131I exposure. DESIGN/SETTING/PARTICIPANTS: Baseline data were collected from the first screening cycle (1998-2000) of a large cohort of radiation-exposed individuals (n = 12,240), residents of contaminated, iodine-deficient territories of Ukraine. Study individuals were under the age of 18 yr on April 26, 1986, and had thyroid radioactivity measurements made shortly after the accident. OUTCOMES: AIT was defined a priori based on various combinations of elevated antibodies to thyroid peroxidase (ATPO), TSH, and clinical findings; elevated ATPO were considered to be an indicator of thyroid autoimmunity. RESULTS: No significant association was found between 131I thyroid dose estimates and AIT, but prevalence of elevated ATPO demonstrated a modest, significant association with 131I that was well described by several concave models. This relationship was apparent in individuals with moderately elevated ATPO and euthyroid, thyroid disease-free individuals. CONCLUSIONS: Twelve to 14 yr after the Chornobyl accident, no radiation-related increase in prevalence of AIT was found in a large cohort study, the first in which 131I thyroid doses were estimated using individual radioactivity measurements. However, a dose-response relationship with ATPO prevalence raises the possibility that clinically important changes may occur over time. Thus, further follow-up and analysis of prospective data in this cohort are necessary.

Effect of long-term freezer storage, thawing, and refreezing on selected constituents of serum.

We determined the effect of long-term freezer storage and repeated thawing and freezing of serum on concentrations of electrolytes (sodium, potassium, calcium, and phosphate), enzymes (aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, and creatine kinase), total protein, tumor markers (carcinoembryonic antigen and alpha-fetoprotein), and other substances. Vials (1 ml) of frozen serum from a single blood drawing from 40 women with no breast disease and 70 with benign breast disease were analyzed annually from 1983 to 1987. Blood had been obtained from 40 subjects in 1978, 40 in 1980, and 30 in 1983. Thawing and refreezing studies were done in two ways: (1) serum samples from 30 subjects with benign breast disease were thawed at weekly intervals for 6 weeks and (2) serum samples from 30 patients with stage IV breast cancer were analyzed for alpha-fetoprotein and carcinoembryonic antigen, and serum specimens from 23 patients with benign breast disease and 7 control subjects were analyzed for lactate dehydrogenase and creatine kinase after thawing and keeping the samples at room temperature for up to 4 hours and then refreezing them. For measuring laboratory variability, duplicate samples were processed. Long-term storage (up to 10 years) and repeated thawing and refreezing did not affect the results of any tested constituents of serum. Although most measurements showed statistically significant variability over test cycles, these differences were thought to be due to laboratory variability.

Serum bank for biological markers for breast cancer.

A bank of serum specimens from women at varying risks of breast cancer has been established. Panels of test specimens can be secured by qualified investigators to evaluate newly discovered biological markers for breast cancer, to verify preliminary data, and to compare performance of established assays among different laboratories. Panels consisting of coded 1-ml vials of sera will be sent upon request to approved investigators. The procedure for application for serum panels is described.

Identification of breast cancer patients with high risk of early recurrence after radical mastectomy: III. Steroid hormones measured in urine.

The relationship of the levels of selected urinary steroid metabolites to breast cancer recurrence after radical mastectomy was studied. An analysis of variance of the steroid measurements suggested that the measurements standardized to per gram of creatinine were the appropriate measure to use in exploring these relationships. No significant associations were found for premenopausal patients; however, for postmenopausal patients, low levels of total 17-ketosteroids were associated with a reduced two-year recurrence-free rate whereas low and high levels of OHA and high levels of total estrogens were associated a relatively low high two-year recurrence-free rate. Because of the large number of significance tests performed and the lack of consistent patterns, it is questionable whether the observed associations are of any importance. Including these steroid quantities in a multivariate regression model along with previously determined clinical prognostic factors indicated that the steroid determinations were the least important variables and did not make a significant contribution to the fit of the model.