Patient-Reported Quality of Life Predicts First-Cycle Pharmacotherapy Survival in Breast Cancer: A Prospective Cohort Study

Objective: Patient-reported outcomes (PROs) provide direct insight into symptom burden and functional status, yet their utility in early pharmacotherapy outcomes in breast cancer remains underexplored. This study investigated whether baseline PROs from the EORTC QLQ-C30 and BR23 questionnaires are associated with and demonstrate discriminative ability for short-term survival during the first pharmacotherapy cycle in breast cancer patients. Methods: We conducted a prospective cohort study at two secondary referral hospitals in Indonesia from January to October 2025. Women with breast cancer initiating systemic pharmacotherapy were enrolled and followed through completion of the first treatment cycle. The primary outcome was survival of the first cycle, defined as a combined endpoint of death or treatment discontinuation due to adverse effects. Baseline demographic, clinical, and tumor characteristics, along with PROs (EORTC QLQ-C30 and BR23), were compared between survivors (n = 99) and non-survivors (n = 7). Statistical comparisons used Mann–Whitney U tests for PROs. Receiver operating characteristic (ROC) curve analyses were performed to evaluate the discriminative performance of PRO domains. Results: Non-survivors were more likely to present with metastatic disease (71.4% vs. 25.3%). Baseline PROs showed marked differences, with survivors reporting higher global health (83.3 vs. 41.7; p < 0.001) and better physical, role, emotional, and social functioning (all p < 0.05). Symptom burden—including pain, appetite loss, constipation, systemic side effects, arm symptoms, and financial difficulty—was higher among non-survivors (all p < 0.05). ROC analysis demonstrated strong discriminative performance for global health status (AUC 0.907; p < 0.001), emotional functioning (AUC 0.846; p = 0.002), and social functioning (AUC 0.843; p = 0.003), with moderate performance for physical functioning (AUC 0.737; p = 0.037). Symptom domains showed lower and inverse AUC values, reflecting scale directionality and limited discriminative capacity. Conclusions: Baseline PROs using EORTC QLQ-C30 and BR23 were strongly associated with early pharmacotherapy survival and demonstrated meaningful discriminative ability, particularly in global and functional domains. Integrating PRO assessments before treatment initiation may enhance early risk stratification, guide supportive care, and improve treatment continuity in breast cancer.