Prognostic factors.

The best predictive models of today can predict no more than 50% of the natural variability of the disease, despite the sophisticated mathematic analyses and the dozens of variables assessed. Clearly, a universe of still unknown prognostic factors remains to be discovered. Analogous to infinity being immeasurable, the fate of the individual patient will never be calculated mathematically. As the discovery of new prognostic factors continues, however, the prediction of the outcome of patients becomes more reliable. Although some prognostic factors (eg, tumor neoangiogenesis and quality of life) are already supported by a large body of evidence, recent research has introduced new groups of prognostic factors (eg, molecular genetic markers and the subclinical activation of coagulation fibrinolysis). Other intriguing factors (eg, a state of mental depression) might also be recognized as important in the near future. A new small portion of the universe has been explored.