Renal cell carcinoma--invasion of veins.

Out of 188 operatively removed renal cell carcinomas 49% showed macroscopic evidence of vein invasion and in 28% of the cases only histologically provable vein invasion. The uncorrected 5-year survival rates amounted to 40.8% in macroscopic vein invasion, 60.6% in histologically provable vein invasion and 75.6% in the absence of vein invasion. The term 'vein invasion' should therefore always be defined more precisely. Hence suggest to modify the V classification of 1974 of the UICC.