Aims: Since 1979 the diseased kidneys of 96 patients on replacement therapy with chronic renal failure due to chronic glomerulonephritis have been followed to investigate the development of acquired cysts and tumors. This is a report of the 20-year follow-up.
Materials and methods: Ninety-six patients were followed using periodic CT scan and were divided into hemodialysis, renal transplantation, bilateral nephrectomy and deceased groups during the follow-up. In the hemodialysis group, 36 patients (19 males, 17 females) were followed for 20 years.
Results: Kidney volumes which were 57.8 (1.51) (geometric mean (geometric SD)) ml at start of the follow-up had become 185.3 (2.03) ml 20 years later in males, and in females, 57.3 (1.64) ml had become 99.7 (2.36) ml. The increased rate was 3.2 (2.06) fold in males and 1.7 (2.57) fold in females. This enlargement of the kidneys was due to acquired cysts. Kidney volumes at the 20-year follow-up had increased more significantly than those at the 15-year follow-up in males; however, kidney volumes at the 20-year follow-up had not changed in females, if compared with data at the 15-year follow-up. Kidney volumes in males at 20-year follow-up were significantly larger than those in females (p = 0.0232). Males with more than 3.2-fold in kidney volume increase at the 20-year follow-up were under the age of 40 at entry into this study (p = 0.0055), although the correlation between the degree of kidney volume increase and age was not significant (p = 0.0910). Kidney volumes in the transplantation group remained small. There was no new renal cell carcinoma development after 15-year follow-up except for the local recurrence of a previous operated case. Although 7 of 44 patients died during the past 20 years due to malignancy, no patient died of renal cell carcinoma because of early detection and treatment. One patient died of retroperitoneal bleeding, which is a complication of acquired renal cystic disease.
Conclusion: Male preponderance of acquired cysts was maintained at the 20-year follow-up. There was a tendency for the rate of increase in acquired renal cystic disease to be larger in young males. No one died of renal cell carcinoma, although the incidence of renal cell carcinoma was high.