Can composite performance measures predict survival of patients with colorectal cancer?

To assess the relationship between long-term colorectal patient survival and methods of calculating composite performance scores.

The Taiwan Cancer Database was used to identify patients who underwent bowel resection for colorectal adenocarcinoma between 2003 and 2004. Patients were assigned to one of three cohorts based on tumor staging: cohort 1, colon cancer stage < III; cohort 2, colon cancer stage III; cohort 3, rectal cancer. A composite performance score (CPS) was calculated for each patient using five different aggregating methods, including all-or-none, 70% standard, equal weight, analytic hierarchy process (AHP), and principal component analysis (PCA) algorithms. The relationships between CPS and five-year overall, disease-free, and disease-specific survivals were evaluated by a Cox proportional hazards model. A goodness-of-fit analysis for all five methods was performed using Akaike's information criterion.

A total of 3272 colorectal cancer patients (cohort 1, 1164; cohort 2, 790; cohort 3, 1318 patients) with a mean age of 65 years were enrolled in the study. Bivariate correlation analysis showed that CPS values from the equal weight method were highly correlated with those from the AHP method in all cohorts (all P < 0.05). Multivariate Cox hazards analysis showed that CPS values derived from equal weight and AHP methods were significantly associated with five-year survivals of patients in cohorts 1 and 2 (all P < 0.05). In these cohorts, higher CPS values suggested a higher probability of five-year survival. However, CPS values derived from the all-or-none method did not show any significant process-outcome relationship in any cohort. Goodness-of-fit analyses showed that CPS values derived from the PCA method were the best fit to the Cox proportional hazards model, whereas the values from the all-or-none model showed the poorest fit.

CPS values may highlight process-outcome relationships for patients with colorectal cancer in addition to evaluating quality of care performance.