LIFETIME ATTRIBUTABLE BREAST CANCER RISK ASSOCIATED WITH RADIATION EXPOSURE FROM CHEST COMPUTED TOMOGRAPHY IN FEMALE COVID-19 PATIENTS IN GEORGIA

Abstract

The study aimed to assess the lifetime attributable risk of breast cancer associated with chest computed tomography (CT) exposure in female COVID-19 patients in Georgia.     Data was obtained from the National Center for Disease Control and Public Health of Georgia (NCDCG), concerning COVID-19 morbidity, hospitalization, and mortality rates for the general population during the period 2020–2021. Additionally, information on the age distribution of breast cancer incidence among the female population in Georgia from 2015 to 2023, as well as demographic data from the National Statistical Office of Georgia for the years 2017 to 2019, was used. Furthermore, data from the First University Clinic in 2020, detailing the age and sex distribution of hospitalized patients and survival-mortality indicators, was also incorporated into the analysis. Population doses were modeled using the Log-Normal distribution with mean 14.16 mGr and median 12.82 mGr for adults and for children 4.58 mGr and 4.47 mGr respectively.  Age structure of study population were evaluated using a Bayesian approach.  A competing risk methodology was employed to estimate both age-conditional and lifetime baseline risks (LBR) of breast cancer development. These estimates were calculated using the United States National Cancer Institute’s DevCan software (version 6.9.0). To determine the age-conditional and lifetime attributable risk (LAR) of radiogenic breast cancer, the methodology outlined in the 2006 report by the Biological Effects of Ionizing Radiation (BEIR) VII Committee of the National Academies of Sciences was applied. Risk computations were performed using the National Cancer Institute’s RadRAT software and the LARisk R package. Monte Carlo simulation techniques were used to estimate uncertainties in risk and subjective uncertainties under various assumptions.      
      It was shown that the lifetime attributable risk for Breast cancer in female COVID patients in Georgia, related to chest computed tomography   in one year is low - 12.77 [90% UR 3.20 - 29.90], and is only 0.2% of the lifetime baseline risk (LBR) for breast cancer. However, for the population under 40 years of age, this ratio is already 2.2%. Overall, the projected number of future breast cancer cases that could be attributed to a chest CT scan performed in one year is 20.06 [90% UR 5.02 - 46.96] cases.     Given the cumulative effects of ionizing radiation and the potential risk of multiple or repeated scanning, further improvements in methods for predicting the long-term effects of medical radiation exposure appear necessary.