Elizabeth K. Cahoon, Ph.D., M.H.S., S.M.

Stadtman Investigator

Radiation Epidemiology Branch


9609 Medical Center Drive
Room SG/7E524
Rockville, MD 20850



Research Topics

Dr. Elizabeth Cahoon’s research focuses on cancer and precancer risks conferred by environmental sources of both ultraviolet and ionizing radiation exposure.

Ultraviolet Radiation and Skin Cancer

Solar radiation is the primary environmental risk factor for most types of skin cancers, which occur in 5 million people and result in over ten thousand deaths each year in the United States. Sensitivity to sunlight is influenced by constitutional characteristics such as skin complexion and, potentially, external factors such as use of photosensitizing medications. Dr. Cahoon is working to identify medications that modify the relationship between UV radiation and skin cancer risks. She has initiated two studies of photosensitizing medications (NSAIDS and estrogen-related factors) in relation to melanoma in the NIH-AARP Diet and Health Study.

To best inform skin cancer prevention, a clearer understanding is needed regarding the influence of timing of UV radiation exposure over the life course, and relative exposure to different UV radiation wavelengths, as a result of sunscreen use, tanning beds, and even window glass. The relative roles of UV radiation wavelengths and skin cancer risks are not known. Dr. Cahoon is evaluating the UV radiation dose-response relationship for skin cancer risks by wavelength, age at exposure, and anatomic site.

In addition, Dr. Cahoon is assessing the role of UV radiation on viral activation, immune modulation, and other mediators of skin (and other) cancer risks.

Ionizing Radiation

Ionizing radiation exposure from occupational, accidental, and medical sources continues to be of public health significance and regulatory concern. Quantification of radiation-related risks provides important information for risk assessment models and risk/benefit analyses of cancer screening programs which rely on radiation for early cancer ascertainment. Dr. Cahoon is examining radiation-related risk for various cancers in the Lifespan Study of Japanese atomic bomb survivors.

Through a collaboration with the National Research Centre for Radiation Medicine in Ukraine, Dr. Cahoon is also leading a thyroid cancer case-control study nested in a cohort of Chernobyl liquidators (i.e., emergency clean-up workers) who were exposed to a wide range of external radiation doses.

Few studies have evaluated the relationship between iodine-131 (I-131) exposure and thyroid nodules, which are potential precursors for thyroid cancer. Dr. Cahoon and colleagues are examining incidence of new thyroid nodules in Belarus and Ukraine and progression of prevalent nodules. Potentially providing a rare window into multistage carcinogenesis, these will be the first studies to evaluate whether nodule characteristics associated with increased risk of thyroid cancer, such as size and vascularization, are apparent at clinical diagnosis or whether these characteristics emerge and evolve over time. 


Dr. Cahoon received her S.M. degree from the Technology and Policy Program in the Engineering Systems Division at MIT, and her M.H.S. in biostatistics and Ph.D. in epidemiology from the Johns Hopkins Bloomberg School of Public Health. She joined the Radiation Epidemiology Branch (REB) as a postdoctoral fellow in 2010 and was promoted to research fellow in 2014. She was appointed to the position of Earl Stadtman Tenure-Track Investigator in 2017. Dr. Cahoon has received numerous awards for her work, including the DCEG Intramural Research Award, the DCEG Outstanding Research Paper by a Fellow, and the NIH Award of Merit.

Selected Publications

  1. Cahoon EK, Kitahara CM, Ntowe E, Bowen EM, Doody MM, Alexander BH, Lee T, Little MP, Linet MS, Freedman DM. Female Estrogen-Related Factors and Incidence of Basal Cell Carcinoma in a Nationwide US Cohort. J Clin Oncol. 2015;33(34):4058-65.

  2. Bowen EM, Pfeiffer RM, Linet MS, Liu WT, Weisenburger DD, Freedman DM, Cahoon EK. Relationship between ambient ultraviolet radiation and Hodgkin lymphoma subtypes in the United States. Br J Cancer. 2016;114(7):826-31.

  3. Cahoon EK, Engels EA, Freedman DM, Norval M, Pfeiffer RM. Ultraviolet Radiation and Kaposi Sarcoma Incidence in a Nationwide US Cohort of HIV-Infected Men. J Natl Cancer Inst. 2017;109(5).

  4. Cahoon EK, Preston DL, Pierce DA, Grant E, Brenner AV, Mabuchi K, Utada M, Ozasa K. Lung, Laryngeal and Other Respiratory Cancer Incidence among Japanese Atomic Bomb Survivors: An Updated Analysis from 1958 through 2009. Radiat Res. 2017;187(5):538-548.

This page was last updated on June 12th, 2017