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In the last three decades, an increase in thyroid cancer incidence has been observed worldwide, as well as in Lithuania. Although the rise was linked to overdiagnosis, the role of lifestyle and environmental factors, including exposure to ionizing radiation, cannot be excluded. In our retrospective study, we aimed to assess the association between the average age-specific thyroid dose due to the radioactive iodine uptake during childhood and adolescence from the Chernobyl fallout in Lithuania, and the trends of incidence of thyroid cancer from 1991 to 2015 in different regions. Averaged age-dependent thyroid doses were estimated for every municipality based on radioiodine activity in milk, reconstructed from available 131I activity measurements in the grass. Thyroid cancer incidence rates were calculated for the entire population and for two age at the time of exposure groups: 0–19 years and 0–9 years. Thyroid cancer relative risk (RR) was estimated for three municipality-specific thyroid dose (for 0-year-old babies) categories: less than 100 mGy (reference group), 100–199 mGy, and ≥200 mGy. Over the study period (1991–2015), a total of 5664 cases of thyroid cancer were registered in the entire Lithuanian population; 817 cases in the age group from 0 to 19 years at the time of the Chernobyl accident, and 266 cases in the age group from 0 to 9 years. Age-standardized thyroid cancer incidence rates have notably increased since 2000, peaked in 2009 (especially in females), and then slightly decreased and stabilized. The estimated average municipality-specific age-dependent thyroid doses ranged from 270 mGy in western Lithuania to 1.5 mGy in central and northern Lithuania. For the age group of 0–19 years at the time of the accident, in the period 1991–1995, the thyroid cancer relative risk was significantly increased (RR 3.91; 95 % CI: 1.27–10.29, p=0.01) in the highest dose category, compared to the lowest (although based on a small number of cases). For the age group 0–9 years at the time of the accident, a tendency of increased RR in the highest dose category appeared in the most recent period, 2011–2015. Our observations need to be confirmed by further following trends of thyroid cancer incidence in the cohort of 0–19-year-old Lithuanians at the time of the Chernobyl accident. • The Chernobyl disaster had a long-term health impact on those exposed to radiation early in life. • The effects of this accident were far-reaching and continue to be studied to this day. • Reconstructed dose of 131I to the thyroid showed a wide range variation among Lithuania's regions. • In areas with doses over 200 mGy in early life, thyroid cancer rates increased for both sexes. [ABSTRACT FROM AUTHOR]

Even 30 years after the accident, an association between breast cancer incidence and ionizing radiation exposure from Chernobyl fallout remains uncertain. We studied breast cancer incidence in the most contaminated regions of Belarus (Gomel and Mogilev) and Ukraine (Kyiv, Zhytomyr and Chernihiv) before (1978‐1986) and after (1987‐2016) the accident. Breast cancer cases and female population size data were received from the national cancer registries and the state departments of statistics. The study included 85 132 breast cancers with 150 million person‐years at risk. We estimated annual rayon (district)‐average absorbed doses to the breast from external and internal irradiation of the adult female population over the period of 1986‐2016. We studied an association between rayon‐average cumulative absorbed breast dose with 5‐year lag, that is, excluding the exposure in 5 years prior to breast cancer diagnosis, and breast cancer incidence using negative binomial regression models. Mean (median) cumulative breast dose in 2016 was 12.3 (5.0) milligray (mGy) in Belarus and 5.7 (2.3) mGy in Ukraine, with the maximum dose of 55 mGy and 54 mGy, respectively. Breast cancer incidence rates statistically significantly increased with calendar year and attained age, and were higher in urban than in rural residents. Adjusting for time, age and urbanicity effects, we found no evidence of increasing incidence with rayon‐average 5‐year lagged cumulative breast dose. Owing to ecological study design limitations, a case‐control study covering this area with individually reconstructed absorbed breast doses is needed testing for association between low‐dose protracted radiation exposure and breast cancer risk after Chernobyl. What's new? The Chernobyl nuclear accident in 1986 exposed various populations, including nearby residents and cleanup workers, to low‐dose ionizing radiation. Here, using national cancer data and data on radionuclide fallout, the authors investigated associations between breast cancer incidence and ionizing radiation exposure in female populations in the most contaminated regions of Belarus and Ukraine following the Chernobyl accident. Analyses indicate that over the period 1986‐2016, breast cancer incidence did not increase in relation to the average 5‐year lagged cumulative breast dose in urban and rural populations. Possible dose misclassification warrants additional investigation via a case‐control study applying individual breast doses. [ABSTRACT FROM AUTHOR]

Abstract: Variation of the stable iodine supply was evaluated in the soils of around more than 700 settlements in the regions (oblasts) of Belarus and the Russian Federation contaminated after the Chernobyl accident. It involved the use of regional information on iodine content in different types of soil cover, biogeochemical criteria of iodine deficiency in food chains, and the available soil maps. The proposed method enabled to create overview maps that differentiated study areas by iodine supply level and to rank rural settlements according to iodine content in soil cover. The area-weighted concentration of stable iodine in the soil cover used for farming was estimated. Median iodine concentration was found to be highest in the settlements of Orel and Tula oblasts (3.6mg/kg), lower in Gomel and Mogilev oblasts (3.0 and 2.3mg/kg, respectively) and lowest in Bryansk and Kaluga oblasts (1.3mg/kg). Estimates of iodine availability from different types of soils were corrected for volumetric weight and adjusted for the type of settlement in order to assign the stable iodine status for each subject in a case–control study of thyroid cancer risk following the Chernobyl accident. The epidemiological study found a significant modifying effect of iodine deficiency on the risk of thyroid cancer following exposure to radioiodines. [ABSTRACT FROM AUTHOR]

• Socio-economic aspects and living conditions contribute to well-being. • Local facilitator-expert-population networks are fruitful structures of dialogue. • Self-help protective actions and counselling are key levers to help the resilience of affected populations. • Strong need of education & training programmes on radiological protection culture. This paper explores how health concerns of populations living in contaminated areas following radiological accidents can be considered in developing health surveillance. The research was performed in the framework of the SHAMISEN project, and aimed at identifying the impacts on, and challenges associated with, living and social conditions of affected populations. These objectives were achieved through the analysis of specific Case Studies in different situations observed after the Chernobyl accident (Belarus and Norway) and the activities carried out after the Fukushima accident. It incorporates an analysis of testimonies of medical experts and local stakeholders from contaminated territories in Japan within two Case Studies as well as through a dedicated workshop jointly organised with Fukushima Medical University in Japan in March 2016. The analysis addresses the following topics: • Expectations and worries of the people regarding their health and welfare; • Role of the different stakeholders (health professionals, radiological protection professionals, local population, authorities, etc.) in improving living and social conditions in contaminated areas; • Contribution of the implemented protective actions to well-being and their direct benefits for populations; • Sustainability and continuity of the projects/actions; • Ethical considerations; • Stakeholder participation, dialogue, information and communication issues; • Education and training provision and need. Thus, this paper outlines key lessons learned from each of these topics, by providing tangibles examples from the analysis of the various Case Studies. [ABSTRACT FROM AUTHOR]

• Thyroid cancer (TC) risk is one of the major concerns after a nuclear accident. • Mass thyroid screening is aimed at complete ascertainment of TC cases, but can lead to over-diagnosis. • Mass thyroid screening may cause adverse side-effects (anxiety, overtreatment). • A mass thyroid screening is not recommended after a nuclear accident. • Thyroid monitoring should be available, with appropriate information and counselling. Exposure of the thyroid gland to ionizing radiation at a young age is the main recognized risk factor for differentiated thyroid cancer. After the Chernobyl and Fukushima nuclear accidents, thyroid cancer screening was implemented mainly for children, leading to case over-diagnosis as seen in South Korea after the implementation of opportunistic screening (where subjects are recruited at healthcare sites). The aim of cancer screening is to reduce morbidity and mortality, but screening can also cause negative effects on health (with unnecessary treatment if over-diagnosis) and on quality of life. This paper from the SHAMISEN special issue (Nuclear Emergency Situations - Improvement of Medical And Health Surveillance) presents the principles of cancer screening, the lessons learned from thyroid cancer screening, as well as the knowledge on thyroid cancer incidence after exposure to iodine-131. The SHAMISEN Consortium recommends to envisage systematic health screening after a nuclear accident, only when appropriately justified, i.e. ensuring that screening will do more good than harm. Based on the experience of the Fukushima screening, the consortium does not recommend mass or population-based thyroid cancer screening, as the negative psychological and physical effects are likely to outweigh any possible benefit in affected populations; thyroid health monitoring should however be made available to persons who request it (regardless of whether they are at increased risk or not), accompanied with appropriate information and support. [ABSTRACT FROM AUTHOR]

• SHAMISEN built upon the experience of past nuclear accidents. • It aimed to develop holistic recommendations to limit impact of nuclear accidents. • SHAMISEN drew lessons about preparedness, response and health surveillance. • SHAMISEN aimed to build resilience/improve well-being in affected populations. Experience suggests that current nuclear accident response planning in European countries mostly has a technical focus, with less attention paid to social, psychological and ethical issues. Information provided tends to be directed towards decisions made by experts, rather than for the support of affected populations. The SHAMISEN (Nuclear Emergency Situations - Improvement of Medical And Health Surveillance) consortium, composed of close to 50 experts from 10 countries, performed a critical review of current recommendations and experiences regarding dose assessment and reconstruction, evacuation decisions, long-term health surveillance programmes and epidemiological studies. The review included case studies and lessons drawn from the living conditions and health status of populations affected by the Chernobyl and Fukushima accidents, taking an integrative approach to health and well-being. Based on this work, SHAMISEN developed a series of comprehensive recommendations aimed at improving the preparedness, response, long-term surveillance and living conditions of populations affected by past or future radiation accidents, in a manner responding to their needs, while minimising unnecessary anxiety. [ABSTRACT FROM AUTHOR]