An analysis of the accuracy of P-POSSUM scoring for mortality risk assessment after surgery for colorectal cancer.

OBJECTIVE: To compare predicted vs. observed mortality using P-POSSUM and determine whether this scoring system reflected observed surgical outcomes. PATIENTS AND METHODS: Consecutive patients who underwent a colorectal resection for cancer over a 12-month period were scored using P-POSSUM to estimate mortality risk and POSSUM to calculate predicted morbidity. This was then compared with observed outcomes. The main outcome measurements were 30 day postoperative mortality and postoperative morbidity.
RESULTS: 173 patients underwent a colorectal resection for cancer during the study period. The observed mortality rate was 8.7% compared with a P-POSSUM predicted mortality rate of 15.6% (P < 0.01). Observed morbidity was 29% whereas the predicted morbidity rate was 32% (P=0.1).
CONCLUSIONS: P-POSSUM allows for standardization of physiological and operative variables. Risk of postoperative mortality may be overestimated by the scoring system however.