Breast cancer risk among thyroid cancer survivors and the role of I-131 treatment.

BACKGROUND: Female thyroid cancer survivors are more likely to have a higher risk of breast cancer compared to the general population, and the underlying causes are yet to be understood. The potential role of I-131 treatment on this association remains controversial. METHODS: We pooled individual data of women who were treated for differentiated thyroid cancer from 1934 to 2005 in France, Italy and Sweden. Standardized incidence ratios (SIRs) for breast cancer were estimated by comparison with age, sex and calendar-year expected values of the general population in each country. We estimated breast cancer risk in relation to I-131 treatment using time-dependent Poisson models. RESULTS: Of 8475 women (mean age at diagnosis: 45 years, range 2-90 years), 335 were diagnosed with breast cancer [SIR = 1.52, 95% confidence interval (CI): 1.36-1.69] during a median follow-up time of 12.7 years since diagnosis. Overall, breast cancer risk did not differ between women treated or not with I-131 (relative risk=1.07, 95% CI 0.84-1.35). However, breast cancer risk increased with increasing cumulative I-131 activity, without significant departure from linearity (excess relative risk per 100 mCi=17%, 95% CI: 2% to 38%). The higher risk associated with a cumulative I-131 activity of ≥100 mCi and ≥400 mCi was translated into 4 (95% CI -4 to 13) and 42 (95% CI -8 to 93) excess breast cancer cases per 10,000 person-years, respectively. CONCLUSIONS: An elevated risk was observed for the highest cumulative administered activity (>=400 mCi), and a significant dose-dependent association was observed among thyroid cancer survivors who were treated with I-131. However, overall, I-131 treatment might only explain partly the increase in breast cancer risk among female thyroid cancer survivors.

Adapted dietary inflammatory index and differentiated thyroid carcinoma risk in two French population-based case-control studies.

PURPOSE: Thyroid cancer is the most common endocrine cancer and its etiology is still not well understood. The aim of the present study was to assess the association between an adapted dietary inflammatory index and differentiated thyroid cancer (DTC) risk in two population-based case-control studies (CATHY and YOUNG-THYR) conducted in France. METHODS: These studies included a total of 1321 DTC cases and 1502 controls, for which an adapted dietary inflammatory index (ADII) was computed based on food frequency questionnaires in each study separately. The association between ADII and thyroid cancer risk was assessed using logistic regression models controlling for potential confounders. RESULTS: Higher ADII scores, corresponding to a higher pro-inflammatory potential of the diet, were associated with higher DTC risk (odds ratio (OR) for 1 standard deviation (SD) increase: 1.09, 95% confidence interval (CI): 1.01, 1.18, P: 0.03). Associations were stronger in analyses restricted to women (OR for 1-SD increase: 1.14, 95% CI 1.04, 1.25, P: 0.005), as well as in women with lower education level, current smoking, or high body mass index. CONCLUSION: Our study suggests that a pro-inflammatory diet is associated with an increased risk of DTC, especially when combined with other inflammatory conditions such as tobacco smoking or overweight. Our findings will help better understand the role of diet-induced inflammation in DTC etiology.

Role of radiotherapy and chemotherapy in the risk of leukemia after childhood cancer: An international pooled analysis.

Childhood cancer survivors are at increased risk for second primary leukemia (SPL), but there is little consensus on the magnitude of some risk factors because of the small size of previous studies. We performed a pooled analysis of all published studies with detailed treatment data, including estimated active bone marrow (ABM) dose received during radiation therapy and doses of specific chemotherapeutic agents for childhood cancer diagnosed from 1930 through 2000, in order to more thoroughly investigate treatment-related risks of SPL. A total of 147 SPL cases (of which 69% were acute myeloid leukemia [AML]) were individually matched to 522 controls, all from four case-control studies including patients from six countries (France, United Kingdom, United States, Canada, Italy and Netherlands). Odds ratios (OR) and corresponding 95% confidence intervals (CIs) were calculated using conditional logistic regression, and the excess OR per Gray (EOR/Gy) was also calculated. After accounting for the other therapies received, topoisomerase II inhibitor was associated with an increased SPL risk (highest tertile vs none: OR = 10.0, 95% CI: 3.7-27.3). Radiation dose to the ABM was also associated with increased SPL risk among those not receiving chemotherapy (EOR/Gy = 1.6, 95% CI: 0.1-14.3), but not among those who received chemotherapy (CT). SPL were most likely to occur in the first decade following cancer treatment. Results were similar when analyses were restricted to AML. The evidence of interaction between radiation and CT has implications for leukemogenic mechanism. The results for topoisomerase II inhibitors are particularly important given their increasing use to treat childhood cancer.

Multiethnic genome-wide association study of differentiated thyroid cancer in the EPITHYR consortium.

Incidence of differentiated thyroid carcinoma (DTC) varies considerably between ethnic groups, with particularly high incidence rates in Pacific Islanders. DTC is one of the cancers with the highest familial risk suggesting a major role of genetic risk factors, but only few susceptibility loci were identified so far. In order to assess the contribution of known DTC susceptibility loci and to identify new ones, we conducted a multiethnic genome-wide association study (GWAS) in individuals of European ancestry and of Oceanian ancestry from Pacific Islands. Our study included 1554 cases/1973 controls of European ancestry and 301 cases/348 controls of Oceanian ancestry from seven population-based case-control studies participating to the EPITHYR consortium. All participants were genotyped using the OncoArray-500K Beadchip (Illumina). We confirmed the association with the known DTC susceptibility loci at 2q35, 8p12, 9q22.33 and 14q13.3 in the European ancestry population and suggested two novel signals at 1p31.3 and 16q23.2, which were associated with thyroid-stimulating hormone levels in previous GWAS. We additionally replicated an association with 5p15.33 reported previously in Chinese and European populations. Except at 1p31.3, all associations were in the same direction in the population of Oceanian ancestry. We also observed that the frequencies of risk alleles at 2q35, 5p15.33 and 16q23.2 were significantly higher in Oceanians than in Europeans. However, additional GWAS and epidemiological studies in Oceanian populations are needed to fully understand the highest incidence observed in these populations.

Identifying clusters of health risk behaviors and their predictors in adult survivors of childhood cancer: A report from the French Childhood Cancer Survivor Study.

OBJECTIVE: Health risk behaviors (HRB) of childhood cancer survivors (CCS) are generally studied separately, despite the evidence suggesting that HRB are not independent. To our knowledge, few studies have examined HRB profiles in the former pediatric cancer patients. In this study, we identified HRB profiles and examined predictors engaging in unhealthy behaviors in CCS. METHODS: We used data from a French cohort of CCS that includes five-year survivors diagnosed between 1945 and 2000 and treated before reaching age 18, in five centers in France. A total of 2961 adult CCS answered a self-reported questionnaire pertaining to HRB. Latent class analysis was used to identify HRB profiles combining physical activity, smoking, cannabis use, and alcohol drinking. Multinomial logistic analyses examined predictors for engaging in unhealthy behaviors. RESULTS: Three HRB patterns emerged: "Low-risk" (n = 1846, 62.3%) included CCS who exhibited the highest frequency for usual physical activity and the lowest probabilities for current smoking or cannabis use, but most drank at least moderately; "Moderate-risk behaviors" (n = 291, 9.8%), and "High-risk behaviors" (n = 824, 27.8%) for CCS who exhibited the highest frequencies for current smoking, cannabis use, and heavy drinking. The multivariable regression revealed that male CCS, less educated or not married were significantly more likely to be in the high-risk behaviors group than the low-risk group. CONCLUSIONS: As CCS remain a vulnerable population, screening for HRB should be routinized in long-term follow-up care and interventions targeting multiple HRB simultaneously among survivors should be developed.

A systematic review of occupational radiation individual dose monitoring among healthcare workers exposed in Africa.

Dosimetric monitoring is useful to limit exposures to ionising radiation in medical occupational settings, and reduce subsequent health risks. Scientific literatures, such as the UNSCEAR report 2017 and International Atomic Energy Agency Report 2014b, updated information on this subject; however, few African works have been found. This is the reason why we undertook this study, which summarises existing information on monitoring external radiation exposure doses for the whole body, using data from medical workers on this continent. Using standard terms and combining different keyword searches for radiation dose monitoring among radiology healthcare workers in Africa, from the titles, abstracts, and full texts, we found 3139 articles in the PubMed/MEDLINE, Google Scholar and INIS databases. Two reviewers screened the retrieved publications based on predefined eligibility criteria to identify relevant studies, extract key information from each, and summarise the data in table form. A total of 20 potentially relevant articles were identified. Among these 20 articles, 15 reported the overall average annual effective dose. Studies included in this systematic review represent an inventory of the radiation protection of medical workers in various African countries, with a focus on the monitoring of occupational radiation exposure. The size of studied populations ranged between 81 and 5152 occupational exposed workers. The mean annual effective doses ranged from 0.44 to 8.20 mSv in all specialities of medical sectors, while diagnostic radiology ranged from 0.07 to 4.37 mSv. For the nuclear medicine and radiotherapy from medical groups, the mean annual effective dose varied between 0.56 and 6.30 mSv. Industrial and research/teaching sectors data varied between 0.38 to 19.40 mSv. In conclusion, more studies implemented on dosimetric monitoring in Africa are needed to get a real picture of occupational exposure in the continent.

Risk of subsequent colorectal cancers after a solid tumor in childhood: Effects of radiation therapy and chemotherapy.

BACKGROUND: Very few previous studies have addressed the question of colorectal cancer (CRC) after childhood cancer treatment. We aimed to quantify the roles of radiation therapy and chemotherapy agents in the occurrence of subsequent CRC. METHODS: A nested case-control study was conducted using 36 CRC cases and 140 controls selected from 7032 five-year survivors of the French Childhood Cancer Survivor Study (FCCSS) cohort, treated from 1945 to 2000 in France. The radiation dose-distribution metrics at the site of CRC and doses of individual chemotherapeutic agents were calculated. Conditional logistic regressions were performed to calculate odds ratios (ORs). RESULTS: Overall, patients who received radiotherapy with estimated dose to colon had a 4.3-fold (95% CI, 1.3-17.6) increased risk for CRC compared with patients who did not receive radiotherapy, after adjustment for chemotherapy. This risk increased to 8.9-fold and 19.3-fold among patients who received radiation doses ranging from 20 to 29.99 Gy and ≥30 Gy, respectively. Our data reported a significantly elevated OR for anthracyclines, after controlling for radiotherapy and MOPP regimen. But, restricted analyses excluding patients who had received ≥30 Gy showed that only radiation doses ranging from 20 to 29.99 Gy produced a significant increase in subsequent CRC risk (OR = 7.8; 95% CI, 1.3-56.0), after controlling for anthracyclines and MOPP regimen. CONCLUSIONS: The risk of subsequent CRC was significantly increased after radiation dose (even < 30 Gy). This novel finding supports the need to update monitoring guidelines for CRC to optimize the long-term follow-up for subsequent CRC in survivors of childhood cancer.

Educational and occupational outcomes of childhood cancer survivors 30 years after diagnosis: a French cohort study.

BACKGROUND: Although survival from childhood cancer has increased, little is known on the long-term impact of treatment late effects on occupational attainment or work ability. METHODS: A total of 3512 five-year survivors treated before the age of 19 years in 10 French cancer centres between 1948 and 2000 were identified. Educational level, employment status and occupational class of survivors were assessed by a self-reported questionnaire. These outcome measures were compared with sex-age rates recorded in the French population, using indirect standardisation. Paternal occupational class was also considered to control for the role of survivors' socioeconomic background on their achievement. Multivariable analyses were conducted to explore clinical characteristics associated with the outcomes. RESULTS: A total of 2406 survivors responded to the questionnaire and survivors aged below 25 years were included in the current analysis. Compared with national statistics adjusted on age and sex, male survivors were more likely to be college graduates (39.2% vs 30.9% expected; P<0.001). This higher achievement was not observed either for leukaemia or central nervous system (CNS) tumour survivors. Health-related unemployment was higher for survivors of CNS tumour (28.1% vs 4.3%; P<0.001) but not for survivors of other diagnoses. Survivors of non-CNS childhood cancer had a similar or a higher occupational class than expected. CONCLUSIONS: Survivors treated for CNS tumour or leukaemia, especially when treatment included cranial irradiation, might need support throughout their lifespan.

Anthropometric Risk Factors for Differentiated Thyroid Cancer in Young Men and Women From Eastern France: A Case-Control Study.

The incidence of thyroid cancer has risen over the past decade, along with a rise in obesity. We studied the role of anthropometric risk factors for differentiated thyroid cancer at the time of diagnosis and at age 20 years in a case-control study conducted in eastern France between 2005 and 2010. The study included 761 adults diagnosed with differentiated thyroid cancer before 35 years of age between 2002 and 2006. They were matched with 825 controls from the general population. Odds ratios were calculated using conditional logistic regression models and were reported for all participants, those with papillary cancer only, and women only. The risk of thyroid cancer was higher for participants with a high body surface area (BSA), great height, or excess weight and for women with a high body fat percentage. Conversely, no significant association was found between body mass index and the risk of thyroid cancer. In the present study, we provide further evidence of the role of BSA and excess weight in the risk of thyroid cancer. These epidemiologic observations should be confirmed by further exploration of the biological mechanisms responsible for the associations of obesity and BSA with thyroid cancer.

Common variants at the 9q22.33, 14q13.3 and ATM loci, and risk of differentiated thyroid cancer in the Cuban population.

BACKGROUND: The incidence of differentiated thyroid carcinoma (DTC) in Cuba is low and the contribution of host genetic factors to DTC in this population has not been investigated so far. Our goal was to assess the role of known risk polymorphisms in DTC cases living in Havana. We genotyped five polymorphisms located at the DTC susceptibility loci on chromosome 14q13.3 near NK2 homeobox 1 (NKX2-1), on chromosome 9q22.33 near Forkhead factor E1 (FOXE1) and within the DNA repair gene Ataxia-Telangiectasia Mutated (ATM) in 203 cases and 212 age- and sex- matched controls. Potential interactions between these polymorphisms and other DTC risk factors such as body surface area, body mass index, size, ethnicity, and, for women, the parity were also examined. RESULTS: Significant association with DTC risk was found for rs944289 near NKX2-1 (OR per A allele = 1.6, 95% CI: 1.2-2.1), and three polymorphisms near or within FOXE1, namely rs965513 (OR per A allele = 1.7, 95% CI: 1.2-2.3), rs1867277 in the promoter region of the gene (OR per A allele = 1.5, 95% CI: 1.1-1.9) and the poly-alanine tract expansion polymorphism rs71369530 (OR per Long Allele = 1.8, 95% CI: 1.3-2.5), only the 2 latter remaining significant when correcting for multiple tests. Overall, no association between DTC and the coding SNP D1853N (rs1801516) in ATM (OR per A Allele = 1.1, 95% CI: 0.7-1.7) was seen. Nevertheless women who had 2 or more pregnancies had a 3.5-fold increase in risk of DTC if they carried the A allele (OR 3.5, 95% CI: 3.2-9.8) as compared to 0.8 (OR 0.8, 95% CI: 0.4-1.6) in those who had fewer than 2. CONCLUSIONS: We confirmed in the Cuban population the role of the loci previously associated with DTC susceptibility in European and Japanese populations through genome-wide association studies. Our results on ATM and the number of pregnancies raise interesting questions on the mechanisms by which oestrogens, or other hormones, alter the DNA damage response and DNA repair through the regulation of key effector proteins such as ATM. Due to the small size of our study and to multiple tests, all these results warrant further investigation.

Repair of ionizing radiation-induced DNA damage and risk of second cancer in childhood cancer survivors.

The study's purpose was to assess whether individuals who developed a second malignant neoplasm (SMN) after treatment for a first malignant neoplasm (FMN) had a lower ability to repair DNA double-strand breaks (DSBs) using a bioassay with γH2AX intensity as a surrogate endpoint. In a case-control study nested in a cohort of childhood cancer survivors, lymphoblastoid cell lines (LCLs) were established from blood samples collected from 94 cases (SMN) and 94 matched controls (FMN). LCLs were irradiated with ionizing radiation (2 and 5 Gy) and γH2AX intensities measured 1, 3, 5 and 24h post-irradiation. Differences in mean γH2AX intensity between cases and controls were compared using Kruskal-Wallis tests. Generalized linear models for repeated measures and conditional logistic regressions for SMN risk estimates were performed. The mean baseline γH2AX intensity measured without irradiation was 9.1 [95% confidence interval (95% CI): 8.5-9.7] in the LCLs from cases and 6.4 (95% CI: 6.0-6.8) from controls (P < 0.001). Markedly higher γH2AX intensity, particularly at 1 h post-irradiation, was also found in the LCLs from the cases compared with the controls for all FMNs and for different types of FMN. Chemotherapy and radiation doses received by bone marrow and thymus for FMN treatment showed a non-significant effect on γH2AX intensity. This case-control study shows that higher baseline and post-irradiation levels of DNA DSBs, as measured by γH2AX intensity, are associated with the risk of SMN in childhood cancer survivors. Further investigations in a prospective setting are warranted to confirm this association.

Menstrual and reproductive factors in the risk of differentiated thyroid carcinoma in young women in France: a population-based case-control study.

The incidence of thyroid cancer has increased in eastern Europe since the Chernobyl nuclear power plant accident. Although the radioactive fallout was much less severe and the thyroid radiation dose was much lower in France, a case-control study was initiated in eastern France. The present study included 633 young women who were diagnosed with differentiated thyroid cancer before 35 years of age between 2002 and 2006 and matched with 677 controls. Face-to-face interviews were conducted from 2005 to 2010. Odds ratios were calculated using conditional logistic regressions and were reported in the total group and by histopathological type of cancer ("only papillary" and "excluding microcarcinomas"). The risk of thyroid cancer was higher in women who had a higher number of pregnancies, used a lactation suppressant, or had early menarche. Conversely, breastfeeding, oral contraceptive use, and late age at first pregnancy were associated with a lower risk of thyroid cancer. No association was observed between thyroid cancer and having irregular menstrual cycle, undergoing treatment for menstrual cycle regularity shortly after menarche, having a cessation of menstruation, use of another contraceptive, history of miscarriage or abortion for the first pregnancy, or having had gestational diabetes. This study confirms the role of hormonal and reproductive factors in thyroid cancer, and our results support the fact that exposure to estrogens increases thyroid cancer risk.

Risk of second bone sarcoma following childhood cancer: role of radiation therapy treatment.

Bone sarcoma as a second malignancy is rare but highly fatal. The present knowledge about radiation-absorbed organ dose-response is insufficient to predict the risks induced by radiation therapy techniques. The objective of the present study was to assess the treatment-induced risk for bone sarcoma following a childhood cancer and particularly the related risk of radiotherapy. Therefore, a retrospective cohort of 4,171 survivors of a solid childhood cancer treated between 1942 and 1986 in France and Britain has been followed prospectively. We collected detailed information on treatments received during childhood cancer. Additionally, an innovative methodology has been developed to evaluate the dose-response relationship between bone sarcoma and radiation dose throughout this cohort. The median follow-up was 26 years, and 39 patients had developed bone sarcoma. It was found that the overall incidence was 45-fold higher [standardized incidence ratio 44.8, 95 % confidence interval (CI) 31.0-59.8] than expected from the general population, and the absolute excess risk was 35.1 per 100,000 person-years (95 % CI 24.0-47.1). The risk of bone sarcoma increased slowly up to a cumulative radiation organ absorbed dose of 15 Gy [hazard ratio (HR) = 8.2, 95 % CI 1.6-42.9] and then strongly increased for higher radiation doses (HR for 30 Gy or more 117.9, 95 % CI 36.5-380.6), compared with patients not treated with radiotherapy. A linear model with an excess relative risk per Gy of 1.77 (95 % CI 0.6213-5.935) provided a close fit to the data. These findings have important therapeutic implications: Lowering the radiation dose to the bones should reduce the incidence of secondary bone sarcomas. Other therapeutic solutions should be preferred to radiotherapy in bone sarcoma-sensitive areas.

The risk of valvular heart disease in the French Childhood Cancer Survivors' Study: Contribution of dose-volume histogram parameters.

BACKGROUND AND PURPOSE: Valvular Heart Disease (VHD) is a known complication of childhood cancer after radiotherapy treatment. However, the dose-volume-effect relationships have not been fully explored. MATERIALS AND METHODS: We obtained individual heart Dose Volume Histograms (DVH) for survivors of the French Childhood Cancer Survivors Study (FCCSS) who had received radiotherapy. We calculated the Mean Dose to the Heart (MHD) in Gy, as well as the heart DVH parameters (Vd Gy, which represents the percentage of heart volume receiving at least d Gy), fixing the thresholds to 0.1 Gy, 5 Gy, 20 Gy, and 40 Gy. We analyzed them furtherly in the subpopulation of the cohort that was treated with a dose lower than 5 Gy (V0.1Gy|V5Gy=0%), 20 Gy (V5Gy|V20Gy=0%), and 40 Gy (V20Gy|V40Gy=0%), respectively. We investigated their role in the occurrence of a VHD in this population-based observational cohort study using the Cox proportional hazard model, adjusting for age at cancer diagnosis and chemotherapy exposure. RESULTS: Median follow-up was 30.6 years. Eighty-one patients out of the 7462 (1 %) with complete data experienced a severe VHD (grade ≥ 3). The risk of VHD increased along with the MHD, and it was associated with high doses to the heart (V40Gy < 50 %, hazard ratio (HR) = 7.96, 95 % CI: 4.26-14.88 and V20Gy|V40Gy=0% >50 %, HR = 5.03, 95 % CI: [2.35-10.76]). Doses 5-20 Gy to more than 50 % (V5Gy|V20Gy=0% >50 %) of the heart induced a marginally non-significant estimated risk. We also observed a remarkable risk increase with attained age. CONCLUSIONS: Our results provide new insight into the VHD risk that may impact current treatments and long-term follow-up of childhood cancer survivors.

Increased Cardiac Risk After a Second Malignant Neoplasm Among Childhood Cancer Survivors: A FCCSS Study.

Background: Childhood cancer survivors (CCS) are at an elevated risk of developing both a second malignant neoplasm (SMN) and cardiac disease. Objectives: This study sought to assess the excess of occurrence of cardiac disease after a SMN among CCS. Methods: Analyses included 7,670 CCS from the French Childhood Cancer Survivors Study cohort diagnosed between 1945 and 2000. To account for the time dependence of the occurrence of a SMN, we employed a landmark approach, considering an additive regression model for the cumulative incidence of cardiac disease. We estimated the effect of a SMN on the instantaneous risk of cardiac disease using a proportional cause-specific hazard model, considering a SMN as a time-dependent exposure. In both models, we adjusted for demographic and treatment information and considered death as a competing event. Results: In 7,670 CCS over a median follow-up of 30 years (IQR: 22-38 years), there were 378 cases of cardiac disease identified, of which 49 patients experienced a SMN. Patients who survived 25 years after their childhood cancer diagnosis and had a SMN in that time frame had a significantly increased cumulative incidence of cardiac disease, which was 3.8% (95% CI: 0.5% to 7.1%) higher compared with those without a SMN during this period. No SMN-induced excess of cardiac disease was observed at subsequent landmark times. SMNs were associated with a 2-fold increase (cause-specific HR: 2.0; 95% CI: 1.4-2.8) of cardiac disease. Conclusions: The occurrence of a SMN among CCS is associated with an increased risk of cardiac disease occurrence and risk at younger ages.

Risk factors for obesity in adulthood among survivors of childhood cancer.

OBJECTIVE: The aim of this study was to identify risk factors for obesity in childhood cancer survivors (CCSs). METHODS: The study included 3199 patients of the French Childhood Cancer Survivor Study cohort, with 303 patients with obesity who had returned the self-questionnaire. Analyses were adjusted for social deprivation index and sex. RESULTS: CCSs were less likely to have obesity (9.5%; 95% CI: 8.5%-10.5%) than expected from the general French population rates (12.5%; p = 0.0001). Nevertheless, brain tumor survivors were significantly more likely to develop obesity than the general French population (p = 0.0001). Compared with patients who did not receive radiotherapy to the pituitary gland, those who received a dose >5 Gy had an increased risk of obesity: relative risk 1.9 (95% CI: 1.2-3.1), 2.5 (95% CI: 1.7-3.7), and 2.6 (95% CI: 1.6-4.3), respectively, for participants with 6 to 20 Gy, 20 to 40 Gy, and ≥40 Gy of radiation. Etoposide administration significantly increased the risk of obesity (relative risk 1.7; 95% CI: 1.1-2.6). High social deprivation index was also a risk factor, just like BMI at diagnosis. CONCLUSIONS: Long-term follow-up of CCSs should include weight follow-up during adulthood.

Dietary patterns, goitrogenic food, and thyroid cancer: a case-control study in French Polynesia.

French Polynesia has one of the world's highest thyroid cancer incidence rates. A case-control study among native residents of French Polynesia included 229 cases of differentiated thyroid cancer diagnosed between 1979 and 2004, and 371 population controls. Dietary patterns and goitrogenic food consumption (cabbage, cassava) were analyzed. We used a factor analysis to identify dietary patterns and a conditional logistic regression analysis to investigate the association between dietary patterns or food items and thyroid cancer risk. Two distinct dietary patterns were identified: traditional Polynesian and Western. A nonsignificant inverse association was observed between the traditional Polynesian dietary pattern and thyroid cancer risk. The Western pattern was not associated with thyroid cancer risk. Cassava consumption was significantly associated with a decreased risk of thyroid cancer. In conclusion, a traditional Polynesian dietary pattern led to a weak reduced risk of thyroid cancer in French Polynesia. The protective effect of cassava on this cancer does not seem to be substantially different from that of cabbage, which was the main goitrogenic food studied to date.

Relationship between the brain radiation dose for the treatment of childhood cancer and the risk of long-term cerebrovascular mortality.

To date, very little is known about the long-term risk of death from cerebrovascular sequelae following childhood cancer treatment. The purpose of this study was to assess the role of treatment in very long-term cerebrovascular mortality following childhood cancer. We studied 4227 5-year survivors of a childhood cancer. Information on chemotherapy was collected and the radiation dose delivered to 11 anatomical sites in the brain was estimated. The main outcome that was considered was death due to cerebrovascular disease occurring before 1 January 2008. After a median follow-up of 29 years, 23 deaths due to cerebrovascular diseases had occurred. In the brain, the radiation dose delivered to the prepontine cistern seemed to play a greater role than the average radiation dose received throughout the brain or the dose to any other specific anatomical site in the brain. The risk of death from cerebrovascular disease increased linearly with the local radiation dose to the prepontine cistern. Each unit of absorbed radiation (Gray) delivered to this area increased the risk by 22% (95% confidence interval: 1-44%). Compared with patients who had not received radiotherapy or who had received <0.1 Gray in the prepontine cistern area, those who had received >50 Gray had a 17.8-fold (4.4-73.0) higher hazard ratio of death from cerebrovascular disease. In conclusion, among 5-year survivors of childhood cancer, the radiation dose to the brain during radiotherapy was significantly associated with long-term cerebrovascular mortality.

Long-term hospitalisations in survivors of paediatric solid tumours in France.

The late effects of treatments for childhood cancers may lead to severe and multiple health conditions requiring hospitalisation. We aimed to estimate the hospitalisation rate among childhood cancer survivors (CCS) in France, to compare them with the general population and to investigate the associated factors. We matched total of 5439 5-year solid CCS diagnosed before the age of 21 between 1945 and 2000 by sex, birth year and region of residence to 386,073 individuals of the French general population. After linkage with the national hospital discharge database, we estimated the relative hospitalisation rate (RHR), the absolute excess risks (AERs) and the relative bed-day ratio (RBDR) during 2006-2018. We used generalised linear models to estimate associations between hospitalisation and survivor characteristics. Overall, the RHR was 2.49 (95% confidence interval [CI] 2.46-2.52) and the RBDR was 3.49 (95% CI 3.46-3.51). We found that neoplasm-related hospitalisations had the highest AER (105.8 per 1000 person-years), followed by genitourinary system diseases (34.4 per 1000 person-years) and cardiovascular diseases (19.2 per 1000 person-years). In adjusted analysis, CCS treated with chemotherapy (risk ratio [RR] 1.62, 95% CI 1.53-1.70), radiotherapy (RR 2.11, 95% CI 1.99-2.24) or both (RR 2.59, 95% CI 2.46-2.73) had a higher risk of hospitalisation than the ones who had not received any of these treatments. CCS treated during the past decades by chemotherapy and/or radiotherapy now had a higher hospitalisation risk for all main categories of diagnosis than the general population. Prevention strategies and medical surveillance programmes may promote a long-term decrease in the hospitalisation rate among CSS.

Experimental Assessment of Workplace Radiation Exposure in Diagnostic X-ray Medical Imaging Centres in Benin from 2019 to 2020.

The ease of prescribing radiological examinations has prompted an expansion in radiological procedures and, consequently, an increase of occupational dose to medical imaging workers. However, little is known about radiation exposure in the workplace of medical radiology professionals in many countries, and in Benin particularly. The purpose of this study was to assess ambient radiation doses in diagnostic X-ray medical facilities in Benin and to observe whether exposure levels are below reference levels. A total of 72 public and private medical imaging centres participated in a cross-sectional study carried out from June 2019 to February 2020 in Benin. These centres had 59 X-ray, four chest and six computed tomography (CT) scan rooms. A calibrated radiameter able to measure short, pulsed or continuous X fields and gamma/beta (50 nSv to 10 Sv) was used to measure exposure levels in these functional rooms. Scattered X-ray doses and exposure time from radiological examinations both behind the lead glass of the control area to assess the levels of exposure of professionals and outside of the examination room to evaluate the level of exposure of the public (including non-exposed workers) have been provided. Equivalent doses estimated per hour were compared with the reference levels of 7.50 and 0.05 µSv per hour for workers and the public, respectively. At the control area, the mean/median (min-max) equivalent doses were 0.09/0.07 (0.00-0.21), 2.39/0.13 (0.00-75.67), and 228.39/28.65 (0.39-869.75) µSv per hour for the chest, X-ray, and CT-scan rooms, respectively. Among 69 examination rooms, 13.04% of the equivalent dose estimated in the workplace behind the lead glass was greater than 7.50 µSv per hour; 65 out of 69 examination rooms showed that 40.00% of the equivalent dose estimated behind the doors was greater than 0.05 µSv per hour. These results demonstrated that current controls, including leaded glass separating the control panel and leaded doors between the examination room and the corridor, are inadequate to limit radiation exposures. The controls must be upgraded and a dosimetry program should be implemented to monitor exposures of employees, patients, and visitors.