1. International Workshop on Radiation and Thyroid Cancer Summary/Conclusions and Recommendations – Day 3 From RERF LSS: Excess relative risk goes down with age of exposure. Excess absolute risk goes up with age, as the baseline goes up. Excess risk seem to linearly related to the dose of radiation to the thyroid. Higher risk at younger age of exposure. In utero risk seems to exist, but the cohort is too small for statistical significance. Session 5

2. International Workshop on Radiation and Thyroid Cancer Summary/Conclusions and Recommendations – Day 3 Russian Studies indicated: Ratio of observed to expected thyroid cancers is highest for those 5 to 10 years of age at exposure. Screening effect is highest from 5 to 10 years after exposure. Ukraine Studies indicated: No increase was seen in thyroid cancer from 1986 to 1992. The first increase seen in children, age 0 to 4 at exposure, began in 1992.

3. International Workshop on Radiation and Thyroid Cancer Summary/Conclusions and Recommendations – Day 3 Belarus Studies indicated: Increase in thyroid cancer began to be observed in Belarus in 1990. Tumors were generally small but often involved metastases, 5 to 6 years after surgery. The Marshall Islands Studies indicated: Radiation exposures were very different than Chernobyl and Fukushima. Although the number of exposed individuals is small, thyroid cancer occurrences are consistent with Chernobyl data. With a diagnosis of thyroid nodules an acceptable medical approach is to observe the nodules over time to determine if surgical removal or other treatments are advisable. The program for the surveillance of thyroid cancer in TEPCO workers is consistent with current medical practices.

4. International Workshop on Radiation and Thyroid Cancer Summary/Conclusions and Recommendations – Day 3 Session 6 Chernobyl experiences: ETHOS & CORE Projects: Increase in thyroid cancer began to be observed in Belarus in 1990. Tumors were generally small but often involved metastases, 5 to 6 years after surgery. French Experiences: La Harg. Although the number of exposed individuals is small, thyroid cancer occurrences are consistent with Chernobyl data. Fukushima With a diagnosis of thyroid nodules an acceptable medical approach is to observe the nodules over time to determine if surgical removal or other treatments are advisable. The program for the surveillance of thyroid cancer in TEPCO workers is consistent with current medical practices.

5. International Workshop on Radiation and Thyroid Cancer Summary/Conclusions and Recommendations – Day 3