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 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 more than 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 risk.

For skin cancer prevention, information on the timing of UV radiation exposure over the life course is important. In addition, despite a shift in our relative exposure to different UV radiation wavelengths due to use of sunscreens, 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 risk by wavelength, age at exposure, and anatomic site.

In addition, Dr. Cahoon is evaluating the role of UV radiation in viral activation, immune modulation, and other mediators of skin (and other) cancer risk. Her previous work identified a relationship between ambient UV radiation and risk of Kaposi sarcoma, possibly through reactivation of the causative virus, human herpesvirus 8. Dr. Cahoon is working to confirm these findings in independent populations.

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 that rely on radiation for early cancer ascertainment. Dr. Cahoon examines radiation-related risk of various cancer types in the Lifespan Study of Japanese atomic bomb survivors and 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 large range of external radiation.

Few studies have evaluated the relationship between I-131 exposure and thyroid nodules, which are potential precursors for thyroid cancer. Dr. Cahoon is 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 B.S.E. in bioengineering from the University of Pennsylvania, her S.M. from the Engineering Systems Division at the Massachusetts Institute of Technology, 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 December 8th, 2017