Questionnaire and Weighted Scoring Formula for Evaluating Clinically Useful Quality-of-Life Scores of Post-Surgical Gastric Cancer Patients

Abstract

Background: As survival rates of cancer patients are improving, the quality-of-life (QoL) is becoming the next significant clinical endpoint. However, most oncology QoL questionnaires fall short in providing clinically useful information for guiding post-surgery care. Consideration of pre-existing health issues and a scoring formula that assigns weights to different scales for patient grading may generate clinically useful QoL scores. Methods: The Quality-of-Life Questionnaire for Post Gastrectomy (QoLQ-PG), which considers pre-existing health issues, comprises 30 items across five scales (general symptom, post-gastrectomy syndrome, activity, psychological state, social relation) and an overall scale. A total of 2524 survey responses from 1035 gastric cancer (GC) patients were collected. Validity and reliability analyses were performed using the multitrait-multimethod matrix. Regression analysis was performed to determine the weight of each scale. Analysis of variance was performed using Fisher's least significant difference test. Findings: The QoLQ-PG showed good reliability, convergent validity, and discriminant validity (Cronbach's alpha: 0.704-0.840; validity diagonal: 0.529-0.786). The scoring formula accurately represented the contributions of the five scales to the overall QoL (R2 = 0.445; p < 0.001), which showed significant correlations (r = 0.228, p < 0.001) with changes in body weight, a decisive clinical index in post-gastrectomy patients. Classification of the QoLQ-PG scores into four grades allowed clear distinction among patient grades, which were also highly correlated with body weight changes (F = 23.12, p < 0.001). Interpretation: The QoLQ-PG reliably illustrated the QoL of post-gastrectomy GC patients in terms of weighted total score and scale scores, which respectively may be used to denote the level and type of post-surgery care needed. The concept and scoring formula of the QoLQ-PG may be adapted in other cancers to evaluate clinically relevant QoL and guide post-treatment plans. Funding Statement: Asan Institute for Life Sciences and Corporate Relations, Asan Medical Center, Korea Declaration of Interests: All authors have no conflicts of interest. Ethics Approval Statement: The Ethics Committee of Asan Medical Center reviewed and approved the study protocol (2015-1288).