Psychometric Properties of the Fear of Progression Questionnaire for Children in Two German Samples (Acute Treatment and Follow-Up Care).

Fear of progression (FoP) is among the most prevalent psychosocial burdens in paediatric oncology. Empirical evidence suggests that FoP is particularly pronounced during acute treatment and often persists into follow-up care. It is associated with heightened perception of physical symptoms, increased post-traumatic stress symptoms, more negative illness perceptions, and reduced quality of life (QoL). Consequently, a comprehensive diagnostic instrument is essential to assess FoP in children with cancer. This study aimed to prospectively validate the German self-report version of the Fear of Progression Questionnaire for Children (FoP-Q-SF/C) aged 7-18 years both during acute treatment and in follow-up care. A total of 116 children participated in the study, including 39 undergoing acute treatment and 77 in follow-up care. Participants completed the FoP-Q-SF/C. Factor analyses were conducted, and associations between FoP and QoL, illness perceptions, posttraumatic stress symptoms, time since diagnosis, cancer type and treatment modality were examined. All items were applicable in children. The FoP-Q-SF/C demonstrated high internal consistency and good convergent, criterion and divergent validity. Consistent with previous research, factor analysis supported a one-factor structure, although findings suggest potential for structural refinement. The FoP-Q-SF/C is a reliable and valid questionnaire for assessing FoP in children with cancer across different treatment phases. It serves as a valuable screening instrument to identify children at risk for elevated psychosocial distress and to guide targeted psychosocial interventions.