Influence of age and nephrectomy on metastatic patterns in Wilms' tumors

Data from 194 autopsy cases of Wilms' tumor were analyzed statistically to investigate the mode of dissemination by classifying them according to the number of organs involved in metastasis, age and history of nephrectomy. Metastasis-free cases were more frequent in cases under two years of age, in bilateral cases, and in non-nephrectomized cases. The frequencies of metastasis to various organs were essentially similar among the various age groups, except those to the contralateral kidney and intestines in cases under two years of age, which were significantly more frequent. Nephrectomized cases showed a significantly higher incidence of metastasis to the peritoneum than non-nephrectomized cases. In cases with metastasis to one organ, metastasis to the lungs, lymph nodes and liver showed low frequencies (17%, 13% and 17%, respectively), but that to the peritoneum showed a rather high frequency (21%). Radiation therapy for the peritoneum after nephrectomy is recommended.