Purpose: To evaluate effects of radiation therapy, chemotherapy, cigarette smoking, and alcohol consumption on the risk of second primary salivary gland cancer (SGC) in the Childhood Cancer Survivor Study (CCSS). Methods and Materials: Standardized incidence ratios (SIR) and excess absolute risks (EAR) of SGC in the CCSS were calculated using incidence rates from Surveillance, Epidemiology, and End Results population-based cancer registries. Radiation dose to the salivary glands was estimated based on medical records. Poisson regression was used to assess risks with respect to radiation dose, chemotherapy, smoking, and alcohol consumption. Results: During the time period of the study, 23 cases of SGC were diagnosed among 14,135 childhood cancer survivors. The mean age at diagnosis of the first primary cancer was 8.3 years, and the mean age at SGC diagnosis was 24.8 years. The incidence of SGC was 39-fold higher in the cohort than in the general population (SIR = 39.4; 95% CI = 25.4-57.8). The EAR was 9.8 per 100,000 person-years. Risk increased linearly with radiation dose (excess relative risk = 0.36/Gy; 95% CI = 0.06-2.5) and remained elevated after 20 years. There was no significant trend of increasing risk with increasing dose of chemotherapeutic agents, pack-years of cigarette smoking, or alcohol intake. Conclusion: Although the cumulative incidence of SGC was low, childhood cancer survivors treated with radiation experienced significantly increased risk for at least 2 decades after exposure, and risk was positively associated with radiation dose. Results underscore the importance of long-term follow up of childhood cancer survivors for the development of new malignancies.
|Original language||English (US)|
|Number of pages||8|
|Journal||International Journal of Radiation Oncology Biology Physics|
|State||Published - Mar 1 2013|
Bibliographical noteFunding Information:
The Childhood Cancer Survivor Study (CCSS) is a collaborative, multi-institutional project, funded as a resource by the National Cancer Institute, of individuals who survived 5 or more years after diagnosis of childhood cancer. The CCSS study population is a retrospectively ascertained cohort of 20,346 childhood cancer survivors diagnosed before age 21 between 1970 and 1986 and approximately 4000 siblings of survivors, who serve as a control group. The cohort was assembled through the efforts of 26 participating clinical research centers in the United States and Canada. Information on how to access and use the CCSS resource is available at www.stjude.org/ccss .