Rasch Analysis of the Esas and Research Implications

Cancer and its treatments—including surgery, chemotherapy, radiation, and hormone therapy—are associated with decreased physical function and adverse psychological and emotional effects. Physical symptoms commonly include fatigue, nausea, pain, and decreased strength and endurance1–4. The importance of appreciating the consequences of cancer-related side effects is magnified as the number of people living with cancer continues to increase5. Evaluating the impact of cancer-related (or treatmentrelated) side effects on patients has evolved beyond physiologic evaluations (for example, changes in hemoglobin levels) to a more holistic view that considers the constellation of symptoms that patients present (for example, pain, nausea, and anxiety)6. The Edmonton Symptom Assessment System (esas) was developed to assess a variety of symptoms often reported by patients in the palliative care setting regardless of their specific diagnosis7. The esas consists of 10 questions evaluating symptoms commonly associated with cancer, including pain, fatigue, nausea, depression, anxiety, drowsiness, appetite, well-being, shortness of breath, and an “other” condition identified as important by the patient7. Each item is scored on a scale ranging from 0 to 10 (maximum score of 100 if all esas items are ABSTRACT