Towards a European prospective data registry for particle therapy.

The evidence for the value of particle therapy (PT) is still sparse. While randomized trials remain a cornerstone for robust comparisons with photon-based radiotherapy, data registries collecting real-world data can play a crucial role in building evidence for new developments. This Perspective describes how the European Particle Therapy Network (EPTN) is actively working on establishing a prospective data registry encompassing all patients undergoing PT in European centers. Several obstacles and hurdles are discussed, for instance harmonization of nomenclature and structure of technical and dosimetric data and data protection issues. A preferred approach is the adoption of a federated data registry model with transparent and agile governance to meet European requirements for data protection, transfer, and processing. Funding of the registry, especially for operation after the initial setup process, remains a major challenge.

Radiation doses received by major organs at risk in children and young adolescents treated for cancer with external beam radiation therapy: a large-scale study from 12 European countries.

BACKGROUND: Childhood cancer survivors are at high risk of long-term iatrogenic events, in particular those treated with radiotherapy. The prediction of risk of such events is mainly based on the knowledge of the radiation dose received to healthy organs and tissues during treatment of childhood cancer diagnosed decades ago. PURPOSE: We aimed to set up a standardised organ dose table in order to help former patients and clinician in charge of long term follow-up clinics. MATERIAL AND METHODS: We performed whole body dosimetric reconstruction for 2646 patients from 12 European Countries treated between 1941 and 2006 (median: 1976). Most planning were 2D or 3D, 46% of patients were treated using Cobalt 60 and 41% using linear accelerator, the median prescribed dose being 27.2 Gy (IQ1-IQ3: 17.6-40.0 Gy), A patient specific voxel-based anthropomorphic phantom with more than 200 anatomical structures or sub-structures delineated as a surrogate of each subject's anatomy was used. The radiation therapy was simulated with a treatment planning system (TPS) based on available treatment information. The radiation dose received by any organ of the body was estimated by extending the TPS dose calculation to the whole-body, by type and localisation of childhood cancer. RESULTS: The integral dose and normal-tissue doses to most of the 23 considered organs increased between the 1950's and the 1970's and decreased or plateaued thereafter. Whatever the organ considered, the type of childhood cancer explained most of the variability in organ dose. The country of treatment explained only a small part of the variability. CONCLUSION: The detailed dose estimates provide very useful information for former patients or clinicians who have only limited knowledge about radiation therapy protocols or techniques, but who know the type and site of childhood cancer, gender, age and year of treatment. This will allow better prediction of the long-term risk of iatrogenic events and better referral to long-term follow-up clinics.

Radiation Therapy Technology Advances and Mitigation of Subsequent Neoplasms in Childhood Cancer Survivors.

PURPOSE: In this Pediatric Normal Tissue Effects in the Clinic (PENTEC) vision paper, challenges and opportunities in the assessment of subsequent neoplasms (SNs) from radiation therapy (RT) are presented and discussed in the context of technology advancement. METHODS AND MATERIALS: The paper discusses the current knowledge of SN risks associated with historic, contemporary, and future RT technologies. Opportunities for research and SN mitigation strategies in pediatric patients with cancer are reviewed. RESULTS: Present experience with radiation carcinogenesis is from populations exposed during widely different scenarios. Knowledge gaps exist within clinical cohorts and follow-up; dose-response and volume effects; dose-rate and fractionation effects; radiation quality and proton/particle therapy; age considerations; susceptibility of specific tissues; and risks related to genetic predisposition. The biological mechanisms associated with local and patient-level risks are largely unknown. CONCLUSIONS: Future cancer care is expected to involve several available RT technologies, necessitating evidence and strategies to assess the performance of competing treatments. It is essential to maximize the utilization of existing follow-up while planning for prospective data collection, including standardized registration of individual treatment information with linkage across patient databases.

Deep-Learning for Rapid Estimation of the Out-of-Field Dose in External Beam Photon Radiation Therapy - A Proof of Concept.

PURPOSE: The dose deposited outside of the treatment field during external photon beam radiation therapy treatment, also known as out-of-field dose, is the subject of extensive study as it may be associated with a higher risk of developing a second cancer and could have deleterious effects on the immune system that compromise the efficiency of combined radio-immunotherapy treatments. Out-of-field dose estimation tools developed today in research, including Monte Carlo simulations and analytical methods, are not suited to the requirements of clinical implementation because of their lack of versatility and their cumbersome application. We propose a proof of concept based on deep learning for out-of-field dose map estimation that addresses these limitations. METHODS AND MATERIALS: For this purpose, a 3D U-Net, considering as inputs the in-field dose, as computed by the treatment planning system, and the patient's anatomy, was trained to predict out-of-field dose maps. The cohort used for learning and performance evaluation included 3151 pediatric patients from the FCCSS database, treated in 5 clinical centers, whose whole-body dose maps were previously estimated with an empirical analytical method. The test set, composed of 433 patients, was split into 5 subdata sets, each containing patients treated with devices unseen during the training phase. Root mean square deviation evaluated only on nonzero voxels located in the out-of-field areas was computed as performance metric. RESULTS: Root mean square deviations of 0.28 and 0.41 cGy/Gy were obtained for the training and validation data sets, respectively. Values of 0.27, 0.26, 0.28, 0.30, and 0.45 cGy/Gy were achieved for the 6 MV linear accelerator, 16 MV linear accelerator, Alcyon cobalt irradiator, Mobiletron cobalt irradiator, and betatron device test sets, respectively. CONCLUSIONS: This proof-of-concept approach using a convolutional neural network has demonstrated unprecedented generalizability for this task, although it remains limited, and brings us closer to an implementation compatible with clinical routine.

Risk of subsequent gliomas and meningiomas among 69,460 5-year survivors of childhood and adolescent cancer in Europe: the PanCareSurFup study.

BACKGROUND: Childhood cancer survivors are at risk of subsequent gliomas and meningiomas, but the risks beyond age 40 years are uncertain. We quantified these risks in the largest ever cohort. METHODS: Using data from 69,460 5-year childhood cancer survivors (diagnosed 1940-2008), across Europe, standardized incidence ratios (SIRs) and cumulative incidence were calculated. RESULTS: In total, 279 glioma and 761 meningioma were identified. CNS tumour (SIR: 16.2, 95% CI: 13.7, 19.2) and leukaemia (SIR: 11.2, 95% CI: 8.8, 14.2) survivors were at greatest risk of glioma. The SIR for CNS tumour survivors was still 4.3-fold after age 50 (95% CI: 1.9, 9.6), and for leukaemia survivors still 10.2-fold after age 40 (95% CI: 4.9, 21.4). Following cranial radiotherapy (CRT), the cumulative incidence of a glioma in CNS tumour survivors was 2.7%, 3.7% and 5.0% by ages 40, 50 and 60, respectively, whilst for leukaemia this was 1.2% and 1.7% by ages 40 and 50. The cumulative incidence of a meningioma after CRT in CNS tumour survivors doubled from 5.9% to 12.5% between ages 40 and 60, and in leukaemia survivors increased from 5.8% to 10.2% between ages 40 and 50. DISCUSSION: Clinicians following up survivors should be aware that the substantial risks of meningioma and glioma following CRT are sustained beyond age 40 and be vigilant for symptoms.

Risk of hematological malignancies from CT radiation exposure in children, adolescents and young adults.

Over one million European children undergo computed tomography (CT) scans annually. Although moderate- to high-dose ionizing radiation exposure is an established risk factor for hematological malignancies, risks at CT examination dose levels remain uncertain. Here we followed up a multinational cohort (EPI-CT) of 948,174 individuals who underwent CT examinations before age 22 years in nine European countries. Radiation doses to the active bone marrow were estimated on the basis of body part scanned, patient characteristics, time period and inferred CT technical parameters. We found an association between cumulative dose and risk of all hematological malignancies, with an excess relative risk of 1.96 (95% confidence interval 1.10 to 3.12) per 100 mGy (790 cases). Similar estimates were obtained for lymphoid and myeloid malignancies. Results suggest that for every 10,000 children examined today (mean dose 8 mGy), 1-2 persons are expected to develop a hematological malignancy attributable to radiation exposure in the subsequent 12 years. Our results strengthen the body of evidence of increased cancer risk at low radiation doses and highlight the need for continued justification of pediatric CT examinations and optimization of doses.

Complete patient exposure during paediatric brain cancer treatment for photon and proton therapy techniques including imaging procedures.

Background: In radiotherapy, especially when treating children, minimising exposure of healthy tissue can prevent the development of adverse outcomes, including second cancers. In this study we propose a validated Monte Carlo framework to evaluate the complete patient exposure during paediatric brain cancer treatment. Materials and methods: Organ doses were calculated for treatment of a diffuse midline glioma (50.4 Gy with 1.8 Gy per fraction) on a 5-year-old anthropomorphic phantom with 3D-conformal radiotherapy, intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT) and intensity modulated pencil beam scanning (PBS) proton therapy. Doses from computed tomography (CT) for planning and on-board imaging for positioning (kV-cone beam CT and X-ray imaging) accounted for the estimate of the exposure of the patient including imaging therapeutic dose. For dose calculations we used validated Monte Carlo-based tools (PRIMO, TOPAS, PENELOPE), while lifetime attributable risk (LAR) was estimated from dose-response relationships for cancer induction, proposed by Schneider et al. Results: Out-of-field organ dose equivalent data of proton therapy are lower, with doses between 0.6 mSv (testes) and 120 mSv (thyroid), when compared to photon therapy revealing the highest out-of-field doses for IMRT ranging between 43 mSv (testes) and 575 mSv (thyroid). Dose delivered by CT ranged between 0.01 mSv (testes) and 72 mSv (scapula) while a single imaging positioning ranged between 2 µSv (testes) and 1.3 mSv (thyroid) for CBCT and 0.03 µSv (testes) and 48 µSv (scapula) for X-ray. Adding imaging dose from CT and daily CBCT to the therapeutic demonstrated an important contribution of imaging to the overall radiation burden in the course of treatment, which is subsequently used to predict the LAR, for selected organs. Conclusion: The complete patient exposure during paediatric brain cancer treatment was estimated by combining the results from different Monte Carlo-based dosimetry tools, showing that proton therapy allows significant reduction of the out-of-field doses and secondary cancer risk in selected organs.

Surveillance after childhood cancer: are survivors with an increased risk for cardiomyopathy regularly followed-up?

BACKGROUND: We aimed to study adherence to cardiac screening in long-term childhood cancer survivors (CCS) at high risk of cardiomyopathy. METHODS: This study involved 976 5-year CCS at high risk for cardiomyopathy from the French Childhood Cancer Survivor Study. Determinants of adherence to recommended surveillance were studied using multivariable logistic regression models. Association of attendance to a long-term follow-up (LTFU) visit with completion of an echocardiogram was estimated using a Cox regression model. RESULTS: Among participants, 32% had an echocardiogram within the 5 previous years. Males (adjusted RR [aRR] 0.71, 95% CI 0.58-0.86), survivors aged 36-49 (aRR 0.79, 95% CI 0.64-0.98), Neuroblastoma (aRR 0.53, 95% CI 0.30-0.91) and CNS tumour survivors (aRR 0.43, 95% CI 0.21-0.89) were less likely to adhere to recommended surveillance. Attendance to an LTFU visit was associated with completion of an echocardiogram in patients who were not previously adherent to recommendations (HR 8.20, 95% CI 5.64-11.93). CONCLUSIONS: The majority of long-term survivors at high risk of cardiomyopathy did not adhere to the recommended surveillance. Attendance to an LTFU visit greatly enhanced the completion of echocardiograms, but further interventions need to be developed to reach more survivors.

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.

Multi-Morbidity and Risk of Breast Cancer among Women in the UK Biobank Cohort.

(Multi-)Morbidity shares common biological mechanisms or risk factors with breast cancer. This study aimed to investigate the association between the number of morbidities and patterns of morbidity and the risk of female breast cancer. Among 239,436 women (40-69 years) enrolled in the UK Biobank cohort who had no cancer history at baseline, we identified 35 self-reported chronic diseases at baseline. We assigned individuals into morbidity patterns using agglomerative hierarchical clustering analysis. We fitted Cox models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer risk. In total, 58.4% of women had at least one morbidity, and the prevalence of multi-morbidity was 25.8%. During a median 7-year follow-up, there was no association between breast cancer risk (5326 cases) and either the number of morbidities or the identified clinically relevant morbidity patterns: no-predominant morbidity (reference), psychiatric morbidities (HR = 1.04, 95%CI 0.94-1.16), respiratory/immunological morbidities (HR = 0.98, 95%CI 0.90-1.07), cardiovascular/metabolic morbidities (HR = 0.93, 95%CI 0.81-1.06), and unspecific morbidities (HR = 0.98, 95%CI 0.89-1.07), overall. Among women younger than 50 years of age only, however, there was a significant association with psychiatric morbidity patterns compared to the no-predominant morbidity pattern (HR = 1.25, 95%CI 1.02-1.52). The other associations did not vary when stratifying by age at baseline and adherence to mammography recommendations. In conclusion, multi-morbidity was not a key factor to help identify patients at an increased risk of breast cancer.

The effect of thyroid dysfunction on breast cancer risk: an updated meta-analysis.

In a previous systematic review and meta-analysis of studies reporting associations between hyper-/hypothyroidism and breast cancer incidence published through 29 January 2019, we identified a higher risk with diagnosed hyperthyroidism compared to euthyroidism, but no association with diagnosed hypothyroidism. This 2-year updated meta-analysis aims to investigate the role of menopause in this association and the dose-response relationship with blood levels of thyroid-stimulating hormone (TSH) and thyroid hormones. After the exclusion of studies with only mortality follow-up, with thyroid dysfunction evaluated as a cancer biomarker or after prior breast cancer diagnosis, we reviewed 25 studies that were published up to 01 December 2021 and identified in MEDLINE, the COCHRANE library, Embase, or Web of Science; of these, 9 were included in the previous meta-analysis. Risk estimates from 22 of the 25 studies were included in the meta-analysis and pooled using random-effects models. Compared to euthyroidism, hyperthyroidism and hypothyroidism diagnoses were associated with higher (pooled risk ratio (RR): 1.12, 95% CI: 1.06-1.18, 3829 exposed cases) and lower risks (RR = 0.93, 95% CI: 0.86-1.00, 5632 exposed cases) of breast cancer, respectively. The increased risk after hyperthyroidism was greater among postmenopausal women (RR = 1.19, 95% CI 1.09-1.30) and the decreased risk after hypothyroidism was more pronounced among premenopausal women (RR = 0.69, 95% CI 0.53-0.89). Among women with no prior history of thyroid disease, every 1 mIU/L increase in TSH level was associated with a 0.8% (95% CI > 0-1.5%) lower risk of breast cancer. In conclusion, this meta-analysis supports an association between thyroid hormone levels and breast cancer risk, which could be modified by menopausal status.

Brain cancer after radiation exposure from CT examinations of children and young adults: results from the EPI-CT cohort study.

BACKGROUND: The European EPI-CT study aims to quantify cancer risks from CT examinations of children and young adults. Here, we assess the risk of brain cancer. METHODS: We pooled data from nine European countries for this cohort study. Eligible participants had at least one CT examination before age 22 years documented between 1977 and 2014, had no previous diagnosis of cancer or benign brain tumour, and were alive and cancer-free at least 5 years after the first CT. Participants were identified through the Radiology Information System in 276 hospitals. Participants were linked with national or regional registries of cancer and vital status, and eligible cases were patients with brain cancers according to WHO International Classification of Diseases for Oncology. Gliomas were analysed separately to all brain cancers. Organ doses were reconstructed using historical machine settings and a large sample of CT images. Excess relative risks (ERRs) of brain cancer per 100 mGy of cumulative brain dose were calculated with linear dose-response modelling. The outcome was the first reported diagnosis of brain cancer after an exclusion period of 5 years after the first electronically recorded CT examination. FINDINGS: We identified 948 174 individuals, of whom 658 752 (69%) were eligible for our study. 368 721 (56%) of 658 752 participants were male and 290 031 (44%) were female. During a median follow-up of 5·6 years (IQR 2·4-10·1), 165 brain cancers occurred, including 121 (73%) gliomas. Mean cumulative brain dose, lagged by 5 years, was 47·4 mGy (SD 60·9) among all individuals and 76·0 mGy (100·1) among people with brain cancer. A significant linear dose-response relationship was observed for all brain cancers (ERR per 100 mGy 1·27 [95% CI 0·51-2·69]) and for gliomas separately (ERR per 100 mGy 1·11 [0·36-2·59]). Results were robust when the start of follow-up was delayed beyond 5 years and when participants with possibly previously unreported cancers were excluded. INTERPRETATION: The observed significant dose-response relationship between CT-related radiation exposure and brain cancer in this large, multicentre study with individual dose evaluation emphasises careful justification of paediatric CTs and use of doses as low as reasonably possible. FUNDING: EU FP7; Belgian Cancer Registry; La Ligue contre le Cancer, L'Institut National du Cancer, France; Ministry of Health, Labour and Welfare of Japan; German Federal Ministry of Education and Research; Worldwide Cancer Research; Dutch Cancer Society; Research Council of Norway; Consejo de Seguridad Nuclear, Generalitat de Catalunya, Spain; US National Cancer Institute; UK National Institute for Health Research; Public Health England.

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.

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.

Pooled Analysis of Meningioma Risk Following Treatment for Childhood Cancer.

Importance: Meningioma is the most common subsequent neoplasm following cranial irradiation among survivors of childhood cancer, but there are still uncertainties regarding the magnitude of the radiation dose-response association, potential modifiers of radiation risks, and the role of chemotherapy. Objective: To evaluate meningioma risk in survivors of childhood cancer following radiotherapy and chemotherapy and identify possible modifying factors of radiation-associated risk. Design, Setting, and Participants: This international case-control study pooled data from 4 nested case-control studies of survivors of childhood cancer diagnosed between 1942 and 2000, followed through 2016. Cases were defined as participants diagnosed with a subsequent meningioma. Controls were matched to cases based on sex, age at first cancer diagnosis, and duration of follow-up. Data were analyzed from July 2019 to June 2022. Exposures: Radiation dose (Gy) to the meningioma site and cumulative chemotherapy doses, including intrathecal and systemic methotrexate doses. Main Outcomes and Measures: The main outcome was subsequent meningioma, assessed using odds ratios (ORs) and excess odds ratios per gray (EOR/Gy). Results: The analysis included 273 survivors of childhood cancer who developed meningioma (cases) and 738 survivors who did not (controls), with a total of 1011 individuals (median [IQR] age at first cancer diagnosis 5.0 [3.0-9.2] years; 599 [59.2%] female). Median (IQR) time since first cancer was 21.5 (15.0-27.0) years. Increasing radiation dose was associated with increased risk of meningioma (EOR/Gy, 1.44; 95% CI, 0.62-3.61), and there was no evidence of departure from linearity (P = .90). Compared with survivors who were not exposed to radiation therapy, those who received doses of 24 Gy or more had more than 30-fold higher odds of meningioma (OR, 33.66; 95% CI, 14.10-80.31). The radiation dose-response association was significantly lower among patients treated at age 10 years or older compared with those treated before age 10 years (EOR/Gy, 0.57; 95% CI, 0.18-1.91 vs 2.20; 95% CI, 0.87-6.31; P for heterogeneity = .03). Risk associated with radiation remained significantly elevated 30 years after exposure (EOR/Gy, 3.76; 95% CI, 0.77-29.15). We found an increased risk of meningioma among children who had received methotrexate (OR, 3.43; 95% CI, 1.56-7.57), but no evidence of a dose-response association or interaction with radiation dose. Conclusions and Relevance: These findings suggest that the meninges are highly radiosensitive, especially for children treated before age 10 years. These results support the reduction in whole-brain irradiation over recent decades and the prioritization of approaches that limit radiation exposure in healthy tissue for children. The persistence of elevated risks of meningiomas for 30 years after cranial radiotherapy could help inform surveillance guidelines.

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.

Smoking and Cannabis Use among Childhood Cancer Survivors: Results of the French Childhood Cancer Survivor Study.

BACKGROUND: Unhealthy behaviors among childhood cancer survivors increase the risks for cancer treatment adverse effects. We aimed to assess tobacco and cannabis use prevalence in this population and to identify factors associated with these consumptions. METHODS: This study involved 2,887 5-year survivors from the French childhood cancer survivor study (FCCSS) cohort. Data on health behaviors were compared with those of controls from the general population. Associations of current smoking and cannabis use with clinical features, sociodemographic characteristics, and health-related quality of life (QOL) were investigated using multivariable logistic regressions. RESULTS: Prevalence for tobacco use was lower in survivors (26%) than in controls (41%, P < 0.001). Among current smokers, survivors smoked more cigarettes per day and started at a younger age than controls. Women, college graduates, older, married, and CNS tumor survivors, as well as those who received chemotherapy and thoracic radiation therapy, were less likely to be smokers and/or cannabis consumers than others. Participants with a poor mental QOL were more likely to smoke. CONCLUSIONS: Preventive interventions and cessation programs must be carried out as early as possible in survivors' life, especially among young males with low educational level and poor mental health. IMPACT: This study brings new insights to health behaviors among childhood cancer survivors from a population with high rates of smoking and cannabis use.

Topographic variability of the normal circle of Willis anatomy on a paediatric population.

Long-term sequelae are major limitations of radiation therapy use, especially for childhood brain tumour. Circle of Willis irradiation strongly increases the long-term risk of stroke, but to establish dose-response relationship, anticipating long-term effects of new techniques, requires to perform accurate and reproducible dosimetric estimations in large cohorts of patients having received radiotherapy decades ago. For the accuracy of retrospective dose reconstruction, the topographic variability of the Circle of Willis arteries is crucial. In order to improve retrospective dosimetric studies and dose-volume estimates to the typical Circle of Willis arteries, we aim to study the inter-individual topographic variability of these structures. Thirty-eight time of flight MRI sequences of children aged 2-17 years in both genders were investigated. A region growth algorithm was used for the segmentation of the cerebral arteries. A rigid registration in a common skull was performed following the anatomy of skull base foramina. The Posterior clinoid processes of the sella turcica were used as reference landmark (R0), and 5 key landmarks were chosen in each segmented Circle of Willis, then distances between the 5 landmarks and R0 were calculated for each of the 38 subjects. The distance between R0 and each landmark of the Circle of Willis followed a normal distribution, the average values ranging from 13.6 to 17.0 mm, and the standard deviations ranged from 2.6 to 3.0 mm, i.e. less than a fifth of the average value. The perimeter of the Circle of Willis was longer in older subjects, this increase being isotropic. Our study shows a remarkably low topographic variability of the typical Circle of Willis. An important result, allowing reliable anthropomorphic phantoms-based retrospective estimations of the radiation doses delivered to these arterial structures during radiotherapy treatment.

Thyroid dysfunction and breast cancer risk among women in the UK Biobank cohort.

This study aimed to evaluate the association between thyroid dysfunction and breast cancer risk. We included 239,436 females of the UK Biobank cohort. Information on thyroid dysfunction, personal and family medical history, medications, reproductive factors, lifestyle, and socioeconomic characteristics was retrieved from baseline self-reported data and hospital inpatient databases. Breast cancer diagnoses were identified through population-based registries. We computed Cox models to estimate hazard ratios (HRs) of breast cancer incidence for thyroid dysfunction diagnosis and treatments, and examined potential confounding and effect modification by comorbidities and breast cancer risk factors. In our study, 3,227 (1.3%) and 20,762 (8.7%) women had hyper- and hypothyroidism prior to the baseline. During a median follow-up of 7.1 years, 5,326 (2.2%) women developed breast cancer. Compared to no thyroid dysfunction, there was no association between hypothyroidism and breast cancer risk overall (HR = 0.93, 95% confidence interval (CI): 0.84-1.02, 442 cases), but we found a decreased risk more than 10 years after hypothyroidism diagnosis (HR=0.85, 95%CI 0.74-0.97, 226 cases). There was no association with hyperthyroidism overall (HR=1.08, 95%CI 0.86-1.35, 79 cases) but breast cancer risk was elevated among women with treated hyperthyroidism (HR=1.38, 95%CI: 1.03-1.86, 44 cases) or aged 60 years or more at hyperthyroidism diagnosis (HR=1.74, 95%CI: 1.01-3.00, 113 cases), and 5-10 years after hyperthyroidism diagnosis (HR=1.58, 95%CI: 1.06-2.33, 25 cases). In conclusion, breast cancer risk was reduced long after hypothyroidism diagnosis, but increased among women with treated hyperthyroidism. Future studies are needed to determine whether the higher breast cancer risk observed among treated hyperthyroidism could be explained by hyperthyroidism severity, type of treatment or aetiology.