Background Patient-reported outcome measures (PROMs) are increasingly used to evaluate and engage in patient's disease management, whilst the use of physician-assessed performance status (PS) is a well-established practice. This study aimed to assess the correlation between patient- and physician reported PS, to identify possible predictors of disagreement, and to examine which performance score convey the greatest prognostic accuracy. We also assessed whether the physical performance scale from the EORTC QLQ C-30 quality of life questionnaire conveyed improved prognostic accuracy compared to both patient and physician reported PS.
Methods Patients were included in a longitudinal observational study of metastatic colorectal cancer patients from central Norway (the mCRC study). At inclusion each patient was assigned an ECOG PS by the treating clinician, and patients completed the patient-reported functional status (PRFS) from the PG-SGA form (a lay version of ECOG PS) and the more comprehensive EORTC QLQ-C30-form. Clinical data (e.g., sex, age, tumor site) was extracted from medical records. Kappa statistics were used to evaluate the agreement between patient- and physician assessed PS, and linear regression was used to detect possible predictors of disagreement. We used the Kaplan-Meier method to estimate median survival time, classified by PRFS and ECOG PS. The Cox hazard regression method was used to evaluate which performance status score best fit survival data.
Results Data from 289 patients was studied. We found fair to moderate agreement between the patient- and physician assessed PS (weighted kappa 0.34 (95%% CI 0.26-0.42)). Physicians tend to rate a significantly better physical function than patients themselves, and discrepancy is higher in younger patients. CEA > 100 µg/L was positively associated with difference in scoring, while age and cognitive functioning were negatively associated with difference in scoring. Disagreement is thus particularly high in young patients, patients with poor cognitive function and higher CEA values. Both patient- and physician assessed PS were independent predictors of survival, but physician assessed PS was most precise. Adding information from the physical performance scale from the EORTC QLQ-C30 questionnaire the physician reported conveyed allover improved prognostic accuracy.
Conclusion Patients tend to rate themselves to be in worse physical function compared to physicians. Age, CEA > 100 µg/L and poor cognitive function are variables associated with difference in scoring. Prognostic accuracy is greatest when viewing information from the physical performance scale from the EORTC QLQ-C30 questionnaire together with the physician assessed PS.