Gastrointestinal Cancer Survival and Radiation Exposure among Atomic Bomb Survivors: The Life Span Study
Menée à partir de données portant sur 7 728 patients ayant survécu à la bombe atomique et atteints d'un cancer gastrointestinal diagnostiqué entre 1958 et 2009, cette étude analyse l'association entre une exposition à différentes doses de radiations avant le diagnostic et la survie spécifique et globale
Background: Radiation exposure is an established risk factor for the development of several forms of cancer, including gastrointestinal cancers. However, few studies have investigated the relationship between pre-diagnostic radiation exposure and survival after cancer diagnosis. Methods: Participants in the Life Span Study (LSS) of atomic bomb survivors who were diagnosed with a first primary invasive stomach, colon, or rectal cancer between 1958-2009 were followed for mortality during 1958-2014. Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of radiation dose from atomic bomb exposure with survival (cancer-specific and overall) after cancer diagnosis. Analyses were adjusted for city of primary exposure, sex, age at diagnosis, and year of diagnosis. Results: We identified 7,728 eligible cancer patients for analysis. We observed no statistically significant associations between radiation dose and cancer-specific survival among LSS participants with a gastrointestinal cancer. Higher radiation doses (≥1 Gy) were suggestively, but not significantly, associated with modestly poorer cancer-specific survival for colon cancer only (HR=1.38, 95% CI: 0.90-2.12), and were associated with poorer overall survival regardless of cancer site. Conclusions: Although radiation exposure is associated with increased risk of gastrointestinal cancer incidence and mortality, study results are inconclusive about an association between pre-diagnostic radiation exposure and survival after gastrointestinal cancer diagnosis. Impact: Radiation exposure from the atomic bomb before gastrointestinal cancer diagnosis was not associated with cancer survival, but should be evaluated in relation to survival for other cancer types.