Classification (staging) of renal parenchymal tumours.

The different classification systems (clinical, microscopic, descriptive) of renal cell tumours provide useful clues to the evaluation and prognosis of these tumours. The prognostic reliability of clinical staging as recommended by UICC is, however, questionable because the clinical parameters are not clearly defined and even the radiological features are of equivocal prognostic significance. Descriptive classification on the basis of the complete surgical specimen is regarded as fundamental to the understanding of the evolution, thus also of the prognosis, of renal cell tumours. The author describes his original staging system of renal cell tumours set forth in 1956 and its modifications in accordance with the recommendations of UICC, taking the stages of evolution (P), involvement of the regional lymph nodes (N+ or N-) and generalization ((M + or M-) into account. The significance of the intracapsular stage ("Stage A") of the tumour is stressed. Renal vein involvement (V+ or V-) is regarded as a less reliable prognostic parameter. For lymph node involvement subdivision into Stages N1-N4 is proposed. The prognostic implications of the descriptive staging system are illustrated in terms of survival figures in a series of 250 cases.