Prognostic factor research in oncology

The prognosis of solid tumors is predominantly influenced by the anatomic e xtent before and after initial treatment. It is defined by the TNM/pTNM sys tem and the residual tumor (R) classification as internationally agreed on and published by the International Union Against Cancer (UICC). However, th ere are several independent factors effective in prognosis in addition to T NM and R. Their identification is the first objective in prognostic factor research. Correctly applied multivariate methods appropriate for the specif ic situation play a key role. Cooperation between clinical oncologists and experienced medical statisticians is indispensable. Putative new prognostic factors have to be carefully evaluated before they can be accepted for gen eral use in clinical oncology. In the future, we have to focus on the devel opment of prognostic systems. Such systems integrate multiple independent p rognostic factors with present staging (TNM, R) to improve the assessment o f prognosis. (C) 1999 Elsevier Science Inc.