Predictors of colorectal cancer surveillance among survivors of childhood cancer at high risk for subsequent colorectal malignancies

Childhood cancer survivors who were treated with ionizing radiation are at a significantly higher risk of developing a subsequent colorectal cancer (CRC) compared to the general population. The Children's Oncology Group (COG) recommends that children and adolescents who were treated with radiation therapy of 30 Gy or more to the abdomen, pelvis, or spine undergo a colonoscopy every five years, beginning at age 35 or 10 years after completion of radiation. Despite these recommendations, research indicates low adherence rates to CRC screening among high-risk childhood cancer survivors. Determining the predictors of attending subsequent colorectal cancer surveillance among individuals in this population is essential to guide interventions aimed at increasing surveillance. This study uses data from the Childhood Cancer Survivor Study (CCSS) and employs the Health Belief Model to identify likely predictors of CRC surveillance (via participation in colonoscopy/sigmoidoscopy or blood stool testing). Predictors include (1) personal health risk perception, (2) health care practices, and (3) cues to screening. Predictors of colonoscopy/sigmoidoscopy participation versus blood stool testing participation were also explored. Of the 711 CCSS survey participants included in this study, 60 (8.4%) reported home stool blood testing in the past year (meeting screening guidelines for the general adult population) and 207 (29.1%) reported having a colonoscopy or sigmoidoscopy in the past 5 years (meeting surveillance recommendations for survivors of childhood cancer treated with radiation). Factors associated with CRC surveillance were age 50 years or older (RR=2.4, 95% CI=1.9-2.9); routine cancer follow-up visit within one year prior to questionnaire completion (RR=1.7, 95% CI=1.2-2.5); physical impairment (RR=1.7, 95% CI=1.2-2.2); and discussion of future cancer risk with a physician at their most recent follow-up visit (RR=1.3, 95% CI=1.1-1.6). More than 70% of childhood cancer survivors at risk for CRC were not screened as recommended. Unless a physician discussed future cancer risk, most survivors were not screened until they reached age 50, the time at which CRC screening is recommended for individuals at average CRC risk. These findings underscore the need for education of survivors and their physicians regarding the heightened CRC risk following radiation.