A pooled analysis of thyroid cancer incidence following radiotherapy for childhood cancer.
Radiat Res
; 178(4): 365-76, 2012 Oct.
Article
em En
| MEDLINE
| ID: mdl-22857014
ABSTRACT
Childhood cancer five-year survival now exceeds 70-80%. Childhood exposure to radiation is a known thyroid carcinogen; however, data are limited for the evaluation of radiation dose-response at high doses, modifiers of the dose-response relationship and joint effects of radiotherapy and chemotherapy. To address these issues, we pooled two cohort and two nested case-control studies of childhood cancer survivors including 16,757 patients, with 187 developing primary thyroid cancer. Relative risks (RR) with 95% confidence intervals (CI) for thyroid cancer by treatment with alkylating agents, anthracyclines or bleomycin were 3.25 (0.9-14.9), 4.5 (1.4-17.8) and 3.2 (0.8-10.4), respectively, in patients without radiotherapy, and declined with greater radiation dose (RR trends, P = 0.02, 0.12 and 0.01, respectively). Radiation dose-related RRs increased approximately linearly for <10 Gy, leveled off at 10-15-fold for 10-30 Gy and then declined, but remained elevated for doses >50 Gy. The fitted RR at 10 Gy was 13.7 (95% CI 8.0-24.0). Dose-related excess RRs increased with decreasing age at exposure (P < 0.01), but did not vary with attained age or time-since-exposure, remaining elevated 25+ years after exposure. Gender and number of treatments did not modify radiation effects. Thyroid cancer risks remained elevated many decades following radiotherapy, highlighting the need for continued follow up of childhood cancer survivors.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Neoplasias da Glândula Tireoide
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Segunda Neoplasia Primária
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Neoplasias
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Neoplasias Induzidas por Radiação
Tipo de estudo:
Incidence_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Adolescent
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Adult
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Child
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Child, preschool
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Female
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Humans
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Infant
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Male
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article