Individual life expectancy estimation using validated prognostic scores for patients with cancer of unknown primary.

PURPOSE: To implement 3 published prognostic scores in an independent set of patients with cancer of unknown primary (CUP), and compare their performance on individual life expectancy prediction. PATIENTS AND METHOD: The survival of 430 consecutive patients with CUP was measured after they had allocated to their prognostic group (good prognosis vs. poor prognosis) according to each prognostic score. Using a 2 x 2 contingency table, we measured the sensitivity, specificity, positive predictive value (PPV) and accuracy of each score in predicting individual outcome (survival <90 days or >180 days). RESULTS: The median overall survival was 189 days (1-4,801 days). Survival was <90 days in 143/421 cases and >180 days in 208/413 cases. The three PPVs were within the same range for prediction of survival <90 days (from 43 to 49%) as well as for prediction of survival >180 days (from 70 to 80%), and underestimate individual life expectancy of 40-50% of the patients. None of the 3 scores appeared significantly better. CONCLUSION: The main finding of this retrospective analysis is that the published prognostic scores cannot be used for rational decision making.