The natural history of tumours of the urinary tract.

Experimental and epidemiological evidence has implicated environmental factors in the increasing incidence of bladder cancer. Papillary tumours are less malignant than solid. Of 36 patients with papillary growths in the renal pelvis, 20 lived five years but 11 of 15 with solid tumours died within one year.Social and geographical influences have affected the incidence of adenocarcinoma of the kidney. Experimentally it has been produced by hormones, carcinogens, viruses and irradiation. Clinically the most adverse factor was histological anaplasia; renal vein invasion was three times as common in high-grade tumours. The postoperative five-year survival was 30 out of 42 patients with low-grade lesions but 12 out of 42 with high-grade lesions. In the case of low malignancy tumours without adverse factors, 25 out of 29 patients survived for five years. This unpredictable behaviour is characteristic of urinary tract tumours.