PT  - JOURNAL ARTICLE
AU  - Bockwoldt, Brandie R
AU  - Sugiyama, Hiromi
AU  - Tsai, Kevin
AU  - Bhatti, Parveen
AU  - Brenner, Alina V.
AU  - Hu, Audrey
AU  - Kerr, Kathleen F
AU  - Morenz, Eric
AU  - French, Benjamin
AU  - Phipps, Amanda I.
TI  - Gastrointestinal Cancer Survival and Radiation Exposure among Atomic Bomb Survivors: The Life Span Study
AID  - 10.1158/1055-9965.EPI-20-1239
DP  - 2020 Jan 01
TA  - Cancer Epidemiology Biomarkers & Prevention
PG  - cebp.1239.2020
4099  - http://cebp.aacrjournals.org/content/early/2020/11/14/1055-9965.EPI-20-1239.short
4100  - http://cebp.aacrjournals.org/content/early/2020/11/14/1055-9965.EPI-20-1239.full
AB  - 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.