Cancer mortality after radiotherapy for a skin hemangioma during childhood

Radiation exposure and leukaemia risk among cohorts of persons exposed to low and moderate doses of external ionising radiation in childhood

BACKGROUND

Many high-dose groups demonstrate increased leukaemia risks, with risk greatest following childhood exposure; risks at low/moderate doses are less clear.

METHODS

We conducted a pooled analysis of the major radiation-associated leukaemias (acute myeloid leukaemia (AML) with/without the inclusion of myelodysplastic syndrome (MDS), chronic myeloid leukaemia (CML), acute lymphoblastic leukaemia (ALL)) in ten childhood-exposed groups, including Japanese atomic bomb survivors, four therapeutically irradiated and five diagnostically exposed cohorts, a mixture of incidence and mortality data. Relative/absolute risk Poisson regression models were fitted.

RESULTS

Of 365 cases/deaths of leukaemias excluding chronic lymphocytic leukaemia, there were 272 AML/CML/ALL among 310,905 persons (7,641,362 person-years), with mean active bone marrow (ABM) dose of 0.11 Gy (range 0-5.95). We estimated significant (P < 0.005) linear excess relative risks/Gy (ERR/Gy) for: AML (n = 140) = 1.48 (95% CI 0.59-2.85), CML (n = 61) = 1.77 (95% CI 0.38-4.50), and ALL (n = 71) = 6.65 (95% CI 2.79-14.83). There is upward curvature in the dose response for ALL and AML over the full dose range, although at lower doses (<0.5 Gy) curvature for ALL is downwards.

DISCUSSION

We found increased ERR/Gy for all major types of radiation-associated leukaemia after childhood exposure to ABM doses that were predominantly (for 99%) <1 Gy, and consistent with our prior analysis focusing on <100 mGy.

Lymphoma and multiple myeloma in cohorts of persons exposed to ionising radiation at a young age

There is limited evidence that non-leukaemic lymphoid malignancies are radiogenic. As radiation-related cancer risks are generally higher after childhood exposure, we analysed pooled lymphoid neoplasm data in nine cohorts first exposed to external radiation aged <21 years using active bone marrow (ABM) and, where available, lymphoid system doses, and harmonised outcome classification. Relative and absolute risk models were fitted. Years of entry spanned 1916-1981. At the end of follow-up (mean 42.1 years) there were 593 lymphoma (422 non-Hodgkin (NHL), 107 Hodgkin (HL), 64 uncertain subtype), 66 chronic lymphocytic leukaemia (CLL) and 122 multiple myeloma (MM) deaths and incident cases among 143,136 persons, with mean ABM dose 0.14 Gy (range 0-5.95 Gy) and mean age at first exposure 6.93 years. Excess relative risk (ERR) was not significantly increased for lymphoma (ERR/Gy = -0.001; 95% CI: -0.255, 0.279), HL (ERR/Gy = -0.113; 95% CI: -0.669, 0.709), NHL + CLL (ERR/Gy = 0.099; 95% CI: -0.149, 0.433), NHL (ERR/Gy = 0.068; 95% CI: -0.253, 0.421), CLL (ERR/Gy = 0.320; 95% CI: -0.678, 1.712), or MM (ERR/Gy = 0.149; 95% CI: -0.513, 1.063) (all p-trend > 0.4). In six cohorts with estimates of lymphatic tissue dose, borderline significant increased risks (p-trend = 0.02-0.07) were observed for NHL + CLL, NHL, and CLL. Further pooled epidemiological studies are needed with longer follow-up, central outcome review by expert hematopathologists, and assessment of radiation doses to lymphoid tissues.

Cognitive effects of low dose of ionizing radiation - Lessons learned and research gaps from epidemiological and biological studies

The last decades have seen increased concern about the possible effects of low to moderate doses of ionizing radiation (IR) exposure on cognitive function. An interdisciplinary group of experts (biologists, epidemiologists, dosimetrists and clinicians) in this field gathered together in the framework of the European MELODI workshop on non-cancer effects of IR to summarise the state of knowledge on the topic and elaborate research recommendations for future studies in this area. Overall, there is evidence of cognitive effects from low IR doses both from biology and epidemiology, though a better characterization of effects and understanding of mechanisms is needed. There is a need to better describe the specific cognitive function or diseases that may be affected by radiation exposure. Such cognitive deficit characterization should consider the human life span, as effects might differ with age at exposure and at outcome assessment. Measurements of biomarkers, including imaging, will likely help our understanding on the mechanism of cognitive-related radiation induced deficit. The identification of loci of individual genetic susceptibility and the study of gene expression may help identify individuals at higher risk. The mechanisms behind the radiation induced cognitive effects are not clear and are likely to involve several biological pathways and different cell types. Well conducted research in large epidemiological cohorts and experimental studies in appropriate animal models are needed to improve the understanding of radiation-induced cognitive effects. Results may then be translated into recommendations for clinical radiation oncology and imaging decision making processes.

Case report: chronic inflammatory ulcer and osteoradionecrosis of the skull following radiotherapy in early childhood

INTRODUCTION

Chronic inflammatory diseases of the skin are the most common differential diagnosis of tumorous lesions of the craniofacial region. Detailed information about a patient's medical history is important for the clinical diagnosis of such cases. Previous radiotherapy should be taken into account, especially in cases of chronic dermatitis, since complications include osteoradionecrois of the adjacent bone strucutres with surrounding inflammation.

CASE REPORT

We present the case of a 77-year-old femal patient who was admitted to our department with a slightly progressive ulcerating lesion of the frontotemporal skull. The patient had received radiotherapy in early childhood as primary therapy for hemangioma. Diagnostic imaging and biopsies revealed a diagnosis of chronic ulceration with underlying osteonecrosis and fibrotic osteomyelitis of the skull. A complex reconstruction of osseous structures and soft tissue was necessary to resolve her complaints.

CONCLUSION

Chronic radiodermatitis and osteoradionecrosis in adults, occurring as late complications, are uncommon, but can be observed even nearly 80 years after radiation. Large defects of the skull require a complete reconstruction to avoid several complications.

Leukaemia and myeloid malignancy among people exposed to low doses (<100 mSv) of ionising radiation during childhood: a pooled analysis of nine historical cohort studies

BACKGROUND

Substantial evidence links exposure to moderate or high doses of ionising radiation, particularly in childhood, with increased risk of leukaemia. The association of leukaemia with exposure to low-dose (<100 mSv) radiation is less certain, although this is the dose range most relevant to the general population. We aimed to estimate the risk of leukaemia associated with low-dose radiation exposure in childhood (age <21 years).

METHODS

In this analysis of historical cohort studies, we pooled eligible cohorts reported up to June 30, 2014. We evaluated leukaemia and myeloid malignancy outcomes in these cohorts with the relevant International Classification of Diseases and International Classification of Diseases for Oncology definitions. The cohorts included had not been treated for malignant disease, had reported at least five cases of the relevant haematopoietic neoplasms, and estimated individual active bone marrow (ABM) doses. We restricted analysis to individuals who were younger than 21 years at first irradiation who had mean cumulative ABM doses of less than 100 mSv. Dose-response models were fitted by use of Poisson regression. The data were received in fully anonymised form by the statistical analyst.

FINDINGS

We identified nine eligible cohorts from Canada, France, Japan, Sweden, the UK, and the USA, including 262 573 people who had been exposed to less than 100 mSv enrolled between June 4, 1915, and Dec 31, 2004. Mean follow-up was 19·63 years (SD 17·75) and mean cumulative ABM dose was 19·6 mSv (SD 22·7). 154 myeloid malignancies were identified (which included 79 acute myeloid leukaemias, eight myelodysplastic syndromes, and 36 chronic myeloid leukaemias, in addition to other unspecified myeloid malignancies) and 40 acute lymphoblastic leukaemias, with 221 leukaemias (including otherwise unclassified leukaemias but excluding chronic lymphocytic leukaemia) identified overall. The fitted relative risks at 100 mSv were 3·09 (95% CI 1·41-5·92; p_trend=0·008) for acute myeloid leukaemia and myelodysplastic syndromes combined, 2·56 (1·09-5·06; p_trend=0·033) for acute myeloid leukaemia, and 5·66 (1·35-19·71; p_trend=0·023) for acute lymphoblastic leukaemia. There was no clear dose-response for chronic myeloid leukaemia, which had a relative risk at 100 mSv of 0·36 (0·00-2·36; p_trend=0·394). There were few indications of between-cohort heterogeneity or departure from linearity. For acute myeloid leukaemia and myelodysplastic syndromes combined and for acute lymphoblastic leukaemia, the dose-responses remained significant for doses of less than 50 mSv. Excess absolute risks at 100 mSv were in the range of 0·1-0·4 cases or deaths per 10 000 person-years.

INTERPRETATION

The risks of acute myeloid leukaemia and acute lymphoblastic leukaemia were significantly increased after cumulative doses of ionising radiation of less than 100 mSv in childhood or adolescence, with an excess risk also apparent for cumulative radiation doses of less than 50 mSv for some endpoints. These findings support an increased risk of leukaemia associated with low-dose exposure to radiation and imply that the current system of radiological protection is prudent and not overly protective.

FUNDING

National Cancer Institute Intramural Research Program, National Cancer Institute, and US National Institutes for Health.

Dosimetric characterization of two radium sources for retrospective dosimetry studies

PURPOSE

During the first part of the 20th century, (226)Ra was the most used radionuclide for brachytherapy. Retrospective accurate dosimetry, coupled with patient follow up, is important for advancing knowledge on long-term radiation effects. The purpose of this work was to dosimetrically characterize two (226)Ra sources, commonly used in Sweden during the first half of the 20th century, for retrospective dose-effect studies.

METHODS

An 8 mg (226)Ra tube and a 10 mg (226)Ra needle, used at Radiumhemmet (Karolinska University Hospital, Stockholm, Sweden), from 1925 to the 1960s, were modeled in two independent Monte Carlo (MC) radiation transport codes: geant4 and mcnp5. Absorbed dose and collision kerma around the two sources were obtained, from which the TG-43 parameters were derived for the secular equilibrium state. Furthermore, results from this dosimetric formalism were compared with results from a MC simulation with a superficial mould constituted by five needles inside a glass casing, placed over a water phantom, trying to mimic a typical clinical setup. Calculated absorbed doses using the TG-43 formalism were also compared with previously reported measurements and calculations based on the Sievert integral. Finally, the dose rate at large distances from a (226)Ra point-like-source placed in the center of 1 m radius water sphere was calculated with geant4.

RESULTS

TG-43 parameters [including gL(r), F(r, θ), Λ, and sK] have been uploaded in spreadsheets as additional material, and the fitting parameters of a mathematical curve that provides the dose rate between 10 and 60 cm from the source have been provided. Results from TG-43 formalism are consistent within the treatment volume with those of a MC simulation of a typical clinical scenario. Comparisons with reported measurements made with thermoluminescent dosimeters show differences up to 13% along the transverse axis of the radium needle. It has been estimated that the uncertainty associated to the absorbed dose within the treatment volume is 10%-15%, whereas uncertainty of absorbed dose to distant organs is roughly 20%-25%.

CONCLUSIONS

The results provided here facilitate retrospective dosimetry studies of (226)Ra using modern treatment planning systems, which may be used to improve knowledge on long term radiation effects. It is surely important for the epidemiologic studies to be aware of the estimated uncertainty provided here before extracting their conclusions.

The risk of childhood leukaemia following exposure to ionising radiation--a review

Since the early years of follow-up of the Japanese atomic-bomb survivors, it has been apparent that childhood leukaemia has a particular sensitivity to induction by ionising radiation, the excess relative risk (ERR) being expressed as a temporal wave with time since exposure. This pattern has been generally confirmed by studies of children treated with radiotherapy. Case-control studies of childhood leukaemia and antenatal exposure to diagnostic x-rays, a recent large cohort study of leukaemia following CT examinations of young people, and a recent large case-control study of natural background γ-radiation and childhood leukaemia have found evidence of raised risks following low-level exposure. These findings indicate that an ERR/Sv for childhood leukaemia of ~50, which may be derived from risk models based upon the Japanese atomic-bomb survivors, is broadly applicable to low dose or low dose-rate exposure circumstances.

Radiotherapy as a risk factor for malignant melanoma after childhood skin hemangioma

The aim of this study was to determine therapy-related risk factors for the development of melanoma after hemangioma. A cohort study was conducted among 4620 patients treated before 16 years of age for skin hemangioma in France. A nested case-control study was also conducted on 13 patients who developed a melanoma (cases) matched with five controls in cohort according to sex, age at the hemangioma diagnostic, the calendar year of occurrence of the hemangioma, and follow-up. The radiation dose received at the site of the melanoma and at the same site in controls was estimated, and named 'local dose'. A total of 13 melanomas were registered during an average follow-up of overall 35 years, the risk of developing melanoma after a hemangioma treatment was 2.5-fold higher [95% confidence interval (CI): 1.4-4.1] compared with that of the general population, this ratio being only 0.8 (95% CI: 0.05-3.6) in 896 patients who did not receive radiotherapy, but 3.0 (95% CI: 1.6-5.1) after radiotherapy. When adjusting on sex, age, and year of the treatment and follow-up duration, melanoma risk was 11.9 (95% CI: 1.4-123) times higher in patients treated with ytrium 90 than in the ones who did not received radiotherapy. In the case-control study, the risk of melanoma was not linked to the local radiation dose. Indeed, the increase in melanoma risk was observed even for very low local doses. Compared with the corresponding skin areas in patients who did not receive radiotherapy, the ones having received less than 0.001 Gy had a melanoma risk of 3.9 (95% CI: 0.5-32) and those who received more than 0.01 Gy had a risk of 6.9 (0.5-99). This study suggests that radiation therapy of skin hemangioma increases the risk of further melanoma, but we were not able to evidence a relation with the local dose. Nevertheless, childhood treated for hemangioma should be considered at risk for developing melanoma and suspicious pigmented lesions should be carefully evaluated even far from treated areas.

Testicular cancer risk associated with occupational radiation exposure: a systematic literature review

Testicular cancer is a rare disease, affecting mainly young men aged 15-49. There have been some recent reports that it might be associated with radiation exposure. We have systematically reviewed this topic. English-language articles published between 1990 and 2008 studying the relationship between occupational radiation exposure and testicular cancer were included. Risk of bias was assessed using a modified version of the EPHPP checklist. For ionising radiation we subdivided study populations into occupational groups. No pooled analysis was performed due to the heterogeneity of studies. Seven case-control and 30 cohort studies were included in the review. For radiation workers, one incidence study showed a significant increase and four showed no effect. Eight mortality studies did not indicate an effect while four showed a non-significant increase. Incidence among persons with military exposure was not increased in two studies and non-significantly increased in another two. Among aircrew studies, one showed no effect against five with slight increases. Medical exposure studies showed no increases. For EMF exposure, three studies showed no effect, two reported a significant and four a non-significant increase in incidence. Overall, there was very limited evidence for associations between occupational ionising radiation and testicular cancer, while there were some positive associations for EMF. Testicular cancer mortality is generally low and was not associated with radiation. New incidence studies are recommended to investigate the association between radiation exposure and testicular cancer where exposure is better specified and individually estimated.

Thyroid adenomas and carcinomas following radiotherapy for a hemangioma during infancy

BACKGROUND AND PURPOSE

A cohort study was performed to investigate the carcinogenic effect of treating skin hemangioma with ionizing radiation during early childhood. This paper presents the incidence of differentiated thyroid adenomas and carcinomas after radiotherapy in this cohort.

METHODS AND MATERIALS

Of a total of 8307 patients treated for a skin hemangioma between 1940 and 1973 at the Institut Gustave-Roussy, 4767 were included in an incidence study, among whom 3795 had received radiotherapy. Seventy-three percent were less than 1-year-old at the time of treatment. External radiotherapy, Radium 226, Strontium 90, Yttrium 90, and Phosphorus 32 were used. The radiation dose received by the thyroid during radiotherapy, estimated in 3497 of the 3795 patients using specific software, was 41 mGy on average. Thyroid tumor cases were obtained by sending out a questionnaire, and were verified in pathological reports. Estimates of thyroid cancer specific incidence rates in the French population were obtained from the French cancer registry network. External and internal analyses were performed.

RESULTS

During an average follow-up of 35 years, 11 patients developed a differentiated thyroid carcinoma and 44 a thyroid adenoma. The incidence of thyroid adenoma was found to be higher among taller and heavier individuals. The incidence of both thyroid carcinoma and adenoma was higher among non-smoker patients. A significant dose-response relationship was found between the radiation dose received by thyroid and the risk of thyroid cancer (Excess Relative Risk per GY, ERR/Gy: 14.7, 95%CI: 1.6-62.9) and of adenoma (ERR/Gy: 5.7, 95%CI: 0.7-19.4).

CONCLUSION

This study confirms that radiation treatment performed in the past for hemangioma during infancy increased the risk of thyroid carcinoma and adenoma. Patients treated with external radiotherapy or with Radium 226 applicators for hemangiomas have to be more specifically followed up because this is the subgroup in whom the highest doses were received by the thyroid gland (more than 90% of the radiation doses were higher than 100 mGy). They are therefore more at risk of developing thyroid cancer.

Basic science and clinical aspects of vascular anomalies

PURPOSE OF REVIEW

Patients with vascular and lymphatic anomalies are often 'medical orphans' ascertained through distinct medical specialists. Multidisciplinary vascular anomalies programs provide focused expertise in diagnosis and treatment for patients. National and international workshops on vascular anomalies are fostering clinical and basic science research to enhance our understanding of vascular development and vascular anomalies. Herewith is presented an update of recent advances in the study of vascular/lymphatic anomalies.

RECENT FINDINGS

New original findings include (1) the identification of distinct cell surface markers and other cellular properties in hemangiomas and vascular malformations relevant to vascular development, (2) the discovery of novel genetic mutations and susceptibility genes in patients with vascular anomalies, (3) recognition of new risk stratifications and clinical issues for patients with hemangiomas and vascular malformations, and (4) the elucidation of sequelae from the disorders as well as side effects of recent and previous therapies for vascular anomalies.

SUMMARY

Vascular anomalies are an attractive model for the study of human disorders of vasculogenesis and angiogenesis. The etiology of these disorders is unclear and likely represents a multifactorial process. Clinical clues are leading to scientific investigations that may enable targeted therapies, prevention strategies, or both.