Long-Term Follow-up for Brain Tumor Development after Childhood Exposure to Ionizing Radiation for Tinea Capitis

Abstract

Ionizing radiation is an established risk factor for brain tumors, yet quantitative information on the long-term risk of different types of brain tumors is sparse. Our aims were to assess the risk of radiation-induced malignant brain tumors and benign meningiomas after childhood exposure and to investigate the role of potential modifiers of that risk. The study population included 10,834 individuals who were treated for tinea capitis with X rays in the 1950s and two matched nonirradiated groups, comprising population and sibling comparison groups. The mean estimated radiation dose to the brain was 1.5 Gy. Survival analysis using Poisson regression was performed to estimate the excess relative and absolute risks (ERR, EAR) for brain tumors. After a median follow-up of 40 years, an ERR/Gy of 4.63 and 1.98 (95% CI = 2.43-9.12 and 0.73-4.69) and an EAR/Gy per 10(4) PY of 0.48 and 0.31 (95% CI = 0.28-0.73 and 0.12-0.53) were observed for benign meningiomas and malignant brain tumors, respectively. The risk of both types of tumors was positively associated with dose. The estimated ERR/Gy for malignant brain tumors decreased with increasing age at irradiation from 3.56 to 0.47 (P = 0.037), while no trend with age was seen for benign meningiomas. The ERR for both types of tumor remains elevated at 30-plus years after exposure.

Cancer risk among chernobyl cleanup workers in Estonia and Latvia, 1986–1998

“…1 Most evidence of increased risk is for therapeutic irradiation occurring during childhood. [31][32][33][34] Although an increased risk of central nervous system tumors was apparent at lower doses among atomic bomb survivors, the dose response for gliomas was not statistically significant, though compatible with the overall estimate. 35 There is no evidence of any excess risk of brain cancer cases (shown as a part of the combined sites of eye, brain and other parts of central nervous system) among the cohort of cleanup workers from Russia for 1991-2001.…”

Strategy for surveying the proteome using affinity proteomics and mass spectrometry

“…A retrospective analysis of 10,834 pediatric patients treated with low-dose radiation (median estimated brain dose of 1.5 Gy) for tinea capitis resulted in 21 cases of malignant tumors (defined as gliomas of all types, including ependymomas) [5]. This represented an ERR/Gy of 1.98 compared to matched controls.…”

Childhood exposure to external ionising radiation and solid cancer risk

“…Four studies that have quantified the risk between IR and brain cancer have reported estimations that vary in terms of the magnitude of the risk per Gy. The Israeli tinea capitis study found an ERR per Gy of 1.98 (95% CI: 0.73 -4.69) for glioma after a mean dose to the brain of 1.5 Gy (range: 1.0 -6.0 Gy) (Sadetzki et al, 2005); a pooled analysis of two Swedish cohorts of infants who received radium treatment for haemangiomas (mean absorbed intracranial dose: 7 cGy; range: 0 -11.5 Gy) estimated the ERR per Gy for all brain tumours as 2.7 (95% CI: 1.0 -5.6) (Karlsson et al, 1998); a childhood cancer survivor study reported an ERR per Gy of 0.33 (95% CI: 0.07 -1.71) for glioma (Neglia et al, 2006) after radiation doses ranging from o1 Gy to 445 Gy; and the LSS found an ERR per Gy for glioma of 0.6 (95% CI: À0.2 to 2.0) (Preston et al, 2002b). Evidence of increasing risk of brain cancer with younger age at exposure has been provided by the first three aforementioned studies ( Figure 1B), whereas for the LSS, the risk was non-significantly higher for those exposed before age 20.…”