Face and content validity of a holistic assessment questionnaire to assess cancer-related fatigue after breast cancer

Background and objective:Cancer-related fatigue (CRF) affects the quality of life after breast cancer. In a previous study, we developed a 72-item questionnaire that assesses CRF from a holistic point of view; named the Holistic Assessment of CRF (HA-CRF) questionnaire. The current study assessed the face and content validity of the HA-CRF questionnaire.Methods:Using a mixed-method approach, ten breast cancer survivors (BCS) did a cognitive walkthrough of the HA-CRF via an app followed by a semi-structured interview about relevancy and essentiality (qualitative). In addition, ten health care professionals (HCPs) assessed the relevancy, clarity, and essentiality of each item via a questionnaire (quantitative).Results:BCS indicated minor textual improvement for four items and six items were not completely clear. The app was considered easy to use and the HC-CRF was on average completed in 18 minutes. The HA-CRF questionnaire provided openness about fatigue and gave the feeling of being heard. The items were helpful and induced self-awareness. HCPs indicated 71% of items being very clear or minor revisions proposed by the minority, with 64% of items being essential and 92% considered relevant.Conclusions:The HA-CRF showed good face and excellent content validity. Further research is needed to assess its ability to monitor in daily life.