Over the last two decades, the use of advanced medical imaging, particularly with computed tomography (CT), has increased dramatically with over 80 million CT scans performed annually in the United States (U.S.). Integrating CT into routine care has contributed to the earlier and more accurate diagnosis of disease and injury. However, it has also markedly increased patient exposure to ionizing radiation, a well-established carcinogen. Many past studies of cancer risk have focused on specific human populations, such as Japanese atomic bomb survivors, which differ from the general US population undergoing routine medical imaging, and while most experts agree that radiation from medical imaging is associated with increased risk of cancer, the magnitude of the risk is unknown. We propose to study pregnant women and children enrolled from 1996 to 2017 in four integrated health care delivery systems: Kaiser Permanente (KP) Northern California, KP Southern California, KP Northwest, and Group Health Cooperative. We will use a stratified nested case-control study with counter-matching to comprehensively evaluate patterns of medical imaging, cumulative exposure to radiation, and subsequent risk of pediatric cancers. The cohort will include health plan members <21 y and pregnant women of any age, focusing on in utero or fetal (prenatal), childhood, and adolescent exposures. We estimate approximately 17.5 million patient-years of follow-up in this population-based study, including approximately 754 cases of pediatric leukemia and 2,779 cases of all pediatric cancers combined.
The aims are to 1) evaluate patterns of medical imaging and associated radiation exposure in pregnant women and pediatric patients (<21 years); and 2) determine the risk of pediatric cancers (<21 years) associated with a) in utero or fetal exposure to medical imaging, focusing on risk of all pediatric cancers and including children born in the health systems with mothers enrolled during pregnancy; b) pediatric exposure to medical imaging, focusing on leukemia and including children born in the health systems; and c) in utero and pediatric exposures, focusing on all pediatric cancers and including children born in the health systems with mothers enrolled during pregnancy. The use of medical imaging with ionizing radiation remains high in the U.S., thus the potential harmful effects of this imaging must be understood so they can be weighed against its diagnostic benefit. This is especially critical for children, because they are particularly vulnerale to the carcinogenic effects of radiation given their rapid growth; in addition, their longer life expectancy gives them more time after exposure than adults to develop a cancer. This proposed study by an inter-disciplinary group of experienced investigators uses unparalleled data resources on U.S. exposure to medical imaging, complete capture of member health care utilization, and detailed demographic and cancer diagnosis information to examine these critical patient care and public health issues.

Public Health Relevance

The use of medical imaging that delivers ionizing radiation is high in the United States. The potential harmful effects of this imaging must be understood so they can be weighed against its diagnostic benefits, and this is especially critical for our vulnerable populations of children and pregnant women. The proposed study will comprehensively evaluate patterns of medical imaging, cumulative exposure to radiation, and subsequent risk of pediatric cancers in four integrated health care delivery systems comprising over 7 million enrolled patients enrolled from 1996-2017.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA185687-04
Application #
9487173
Study Section
Health Services Organization and Delivery Study Section (HSOD)
Program Officer
Lai, Gabriel Y
Project Start
2015-03-01
Project End
2020-05-31
Budget Start
2018-06-01
Budget End
2019-05-31
Support Year
4
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of California San Francisco
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94118
Smith-Bindman, Rebecca; Kwan, Marilyn L; Miglioretti, Diana L (2016) Who Gets to Decide? Radiology 278:635-6