Psychometric evaluation of the Impact of Cancer (IOC-CS) scale for young adult survivors of childhood cancer.

Introduction: Psychosocial outcomes derived from standardized and disease-specific measures are often used in pediatric oncology; however, the reliability, validity and utility of these instruments in adult survivors of childhood cancer have yet to be established.

Purpose: To develop and evaluate a new instrument that measures aspects of long-term survivorship not measured by existing tools.

Methods: A new candidate instrument--the Impact of Cancer for childhood cancer survivors (IOC-CS)--was administered to childhood cancer survivors aged 18-39 who were 21 years of age or younger when diagnosed with cancer. Psychometric properties of newly derived scales were assessed.

Results: Factor analyses of items derived eight new and specific subscales: Life Challenges, Body/Health, Talking With Parents, Personal Growth, Thinking/Memory Problems, Health Literacy, Socializing and Financial Problems. Internal consistency measurements for these subscales ranged from 0.70 to 0.86. Expected associations within and among the IOC-CS subscales and standardized measures of health-related quality of life (HRQOL) were observed, as were some unexpected findings.

Conclusion: Psychometric analyses indicated that this initial version of the IOC-CS measures distinct and relevant constructs for young adult survivors of childhood cancer. Future work is necessary to confirm the responsiveness and further validate the instrument in multiple and representative samples.