Emily Matson, Brigham Young University
Health
Cancer, despite its common association with old age, is a leading cause of death for children age 1-14, second only to unintentional injuries. Improvements in diagnosis and treatment are increasing childhood cancer survival, and more research is needed on the risk of subsequent cancer following an initial diagnosis, of either the same or another site. Research on associations between childhood and secondary cancers may improve patient follow-up by providing health professionals with information about which subsequent cancers are likely to occur, which screenings to conduct and what symptoms to look for.
The Childhood Cancer Survivor Study is a comprehensive body of information on childhood cancer and risk of subsequent primary malignancy. In the U.S., the definitive source of cancer incidence and survival data is the Surveillance Epidemiology and End Results (SEER) Program of the National Cancer Institute, with data from 1973 to 2010. The purpose of this study is to assess the risk of subsequent primary malignancies following an initial diagnosis of several childhood cancers, using SEER data and the International Classification for Childhood Cancer. SEER*Stat, a statistical software product for SEER data analysis, was used to calculate multiple primary standardized incidence ratios, which represent the observed divided by the expected number of cancer cases following initial cancer diagnosis. These results were compared with existing study results from the literature.
Of the cancers studied, primary retinoblastomas had the highest ratio of observed/expected secondary neoplasms (10.3), while thyroid carcinoma resulted in the lowest (1.6). All cancer types had a significant increased risk of subsequent cancer.
Typically 15.1 years separated the first and subsequent neoplasm. This gap is four to five years longer than indicated by studies in the literature review. The difference may result from treatment improvements over time and the specific cancer types and treatment methods studied in previous cohorts.