Second neoplasms after Wilms' tumor in childhood.

The frequency of second neoplasms was examined among 487 Wilms' tumor patients treated at the Dana-Farber Cancer Institute and Children's Hospital of Boston, 1927-81. Thirty study patients (6%) developed second primary tumors: 11 cancers, 16 benign tumors, and 3 borderline neoplasms. Cumulative probability of a second cancer was 18% (standard error, 6%) in 34 years after diagnosis of Wilms' tumor. The subgroup of 412 patients who had received radiotherapy for Wilms' tumor developed all 11 second cancers, which included 1 skin carcinoma, 1 acute leukemia, and 9 solid internal cancers (expected, 0.7 cancers other than skin carcinoma; P less than .001). After exclusion of the secondary leukemia, all but 1 second cancer arose within the radiotherapy field. Concurrent therapy with dactinomycin did not reduce the risk of a radiation-associated cancer. Second cancer was the cause of death in 7 patients.