Development and Validation of a Symptom Scale to Evaluate Postoperative Patients with Esophagogastric Cancer

Abstract

Postgastrectomy or esophagectomy symptoms can be a significant burden for patients. However, no standard scale for evaluating these symptoms has been established. We recently developed a postoperative symptom-specific scale. After a draft scale was prepared based on a pilot study, psychometric methods were used to assess its reliability and validity. This study involved specialized and multifaceted discussions by a team consisting of gastrointestinal surgeons, gastroenterologists, psychologists, and epidemiologic researchers. The draft questionnaire included 40 questions and 3 domains. A factor analysis was carried out to refine the items and subscale design. To assess the reliability, Cronbach's alpha and score distributions were estimated. To assess the criterion-related validity, the correlations with the Short Form (SF)-12, Gastrointestinal Symptom Rating Scale (GSRS), endoscopic findings, and nutritional indicators were analyzed. A total of 344 patients were enrolled in this study. In an exploratory factor analysis (principal factor method), the eigenvalue attenuation data showed 4 domains. The final scale, named the Esophagus and Stomach Surgery Symptom Scale (ES(4)), included 23 items and 4 domains; 7 items for cervico-thoracic symptoms, 6 for abdominal hypersensitivity symptoms, 4 for abdominal distention symptoms, and 6 items for systemic symptoms. Cronbach's alphas for these domains were 0.82, 0.81, 0.79, and 0.74, respectively. The scale scores were normally distributed, and there were significant associations with the endoscopic findings, nutritional indicators, the summary score of the SF-12, and the GSRS. The ES(4) scale has high psychometric validity and can evaluate the profiles and severity of postoperative symptoms. This scale is applicable as an outcomes measure for various interventional studies on esophagogastric surgery aimed at alleviating postoperative symptoms.