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

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 5 years) 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.