Wilms' tumor: evaluation of treatment methods.

Abstract

The treatment of Wilms' tumor of the kidney has been a controversial subject for many years. There has been fairly unanimous agreement as to the necessity for surgical removal of the affected kidney if a cure is to be expected, although even this has been disputed by some authors (16). But the advisability of preoperative and postoperative irradiation has never been established from adequately controlled clinical studies. For this reason it was thought desirable to review the literature and analyze the reported cures in an attempt to evaluate irradiation before and after surgery as an adjunct in the treatment of this condition. Historical The first case report of an embryonal kidney tumor was that of Gairdner in 1828 (25). He called the lesion “fungus haematodes,” and many other names have been used in describing it since that time. In the 121 years since Gairdner's original report, many hundreds of cases have been added to the literature. The name of Wilms was applied to the tumor following his classical monograph in 1899 (79). This designation has been in general use since that time. In more recent years, with the trend toward avoidance of proper names in connection with disease entities, the more descriptive terms of embryoma and adenomyosarcoma have been used. Birch-Hirschfeld introduced the term embryonal adenosarcoma in 1898 (6). Incidence According to Campbell (12), Wilms' tumor comprises 20 per cent of all the malignant tumors in infancy and childhood. The disease is seen characteristically in the young, 75 per cent of the cases occurring before five years of age. Gross and Microscopic Appearances Adequate descriptions of the gross and microscopic appearance have been published elsewhere and need not be repeated here. It is important, however, to emphasize the embryonal nature of the tumor because of the relationship to its radiosensitivity. All authors seem agreed as to the embryonic origin, although there is some disagreement as to the stage of development at which the tumor appears. Dean and Pack (19) explain this disagreement logically by the fact that in different cases the tumor arises at different stages in the development of the kidney and hence presents the varying histologic appearances which have led to the controversy. The different degrees of radiosensitivity of the tumor are dependent upon the proportion of embryonal sarcomatous cells to epithelial cells. The former are radio-sensitive, the latter radioresistant. The marked reduction in size of the tumors which occurs with irradiation is due to destruction of the sarcomatous elements, while the tendency to recur with cessation of irradiation is due to the viability of the resistant epithelial cells. Symptoms Wilms' tumors are characterized by their lack of symptoms. The one constant and outstanding feature is the presence of an abdominal mass, which is usually discovered accidentally by the parents or nurse, or during a routine examination by the physician.