The prognostic value of patient-reported outcomes (PROs) has been minimally explored in advanced breast cancer, and their comparative predictive performance against Eastern Cooperative Oncology Group performance status (ECOG-PS) is largely unknown.
This study pooled individual participant data from clinical trials CLEOPATRA, EMILIA, and MARIANNE. Pre-treatment PRO associations with overall survival (OS) and progression-free survival (PFS) were evaluated via Cox proportional hazards regression. Prediction performance was assessed with the C-statistic (c). PRO values were collected via the functional assessment of the cancer therapy-breast (FACT-B) questionnaire. All analyses were stratified by study and treatment arms. Analyses adjusted for known prognostic variables were conducted.
The study included data from 2894 patients initiated on contemporary therapies including pertuzumab (n=765), trastuzumab (n=1173), trastuzumab emtansine (n=1225), taxanes (n= 1173), lapatinib (n= 496), and capecitabine (n=496). The study included data from 1903 patients initiating first-line therapy for advanced disease and 991 patients initiating later-line therapy. On univariable and adjusted analysis, patient-reported physical well-being, functional well-being, breast cancer subscale, and emotional well-being were all identified to be associated with OS and PFS (p<0.05). The OS prediction performance of physical well-being (c=0.59) was superior to ECOG-PS (c=0.56), with multivariable analysis indicating both provide independent information (p<0.0001).
PROs were identified as independent prognostic factors for OS and PFS in patients with HER2-positive advanced breast cancer-initiating contemporary treatment options. Furthermore, patient-reported physical well-being was more predictive of OS than ECOG-PS and contained independent information. PROs have value as prognostic and stratification factors for clinical use and research trials of anti-cancer medicines in HER2-positive advanced breast cancer.