Assessing the impact of cancer: development of a new instrument for long-term survivors.

ABSTRACT

OBJECTIVE: To develop and evaluate a new instrument that measures aspects of long-term survivorship not measured by existing tools. METHODS: In qualitative interviews, 47 long-term cancer survivors (LTS) detailed ways that cancer has impacted their lives. Content analysis resulted in the creation of 325 candidate items for inclusion in a new Impact of Cancer (IOC) instrument. Following expert review, item reduction and pilot testing, 81 items were administered with other established health status and quality of life (QOL) instruments to 193 LTS of breast, prostate, colorectal cancers and lymphoma. Internal consistency reliability and validity of newly-derived scales was assessed. RESULTS: Factor analysis of items using a priori QOL domains resulted in the derivation of ten new and specific subscales Health Awareness, Body Changes, Health Worries, Positive and Negative Self-Evaluation, Positive and Negative Life Outlook, Social Life Interferences, Relationships, and Meaning of Cancer. Internal consistency measurements for these subscales ranged from 0.67 to 0.89. Expected associations within and among the IOC subscales and standardized measures of health status and QOL were observed, as were some unexpected findings. CONCLUSIONS: Psychometric analysis indicated that this initial version of the Impact of Cancer instrument measures distinct and relevant constructs for LTS. Future work is necessary to confirm the factor structure, responsiveness and further validation of the instrument.