The Impact of Cancer Scale (IOC) in Italian long-term cancer survivors: adaptation and psychometric evaluation

Abstract

The Impact of Cancer Scale (IOC) is a self-assessment tool designed to capture the unique and multidimensional aspects of the quality of life of long-term cancer survivors. This paper describes the adaptation and psychometric evaluation of its Italian version. After the adaptation (i.e., removal of nonpertinent items and back-translation procedure), the Italian version of IOC has been administered to a sample of Italian long-term cancer survivors (people free from cancer and its treatments for at least 5years) together with the Short Form 36 Health Survey Questionnaire, the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30, and the Post-Traumatic Growth Inventory. Data on 304 participants were analyzed. Exploratory factor analysis revealed a three-factor structure composed of Uncertainty/Worry about Health & Future (13 items), Personal Growth & Altruism (14 items), and Dissatisfaction & Life Interferences (10 items). Internal consistency (Cronbach's alpha, >0.77) and temporal stability (Spearman's rho, >0.70) were good for all three factors. The obtained three factors correlated with the theoretically pertinent subscales of the other administered tools. To facilitate cross-cultural comparisons, reliability and convergent/divergent validity data for the eight-factor IOC structure already described in literature (Impact of Cancer Version 2) have been also provided. This study supports the use of the IOC in Italy as a trifactorial instrument that is able to isolate aspects characteristic of the condition of long-term cancer survivorship. However, subsequent studies are needed to confirm these findings as well as shed more light on the validity of the IOC construct and its cultural variability.