Second non-germ cell malignancies after radiotherapy of testicular cancer with or without chemotherapy.

The incidence of a new primary non-germ cell malignancy was determined in 876 patients with testicular cancer treated at the Norwegian Radium Hospital from 1956 to 1977. Sixty-five patients developed a second cancer leading to a statistically significant increased relative risk (RR = 1.58), especially if extended radiotherapy had been given (RR = 4.13). The excess risks of developing lung cancer and malignant melanoma were 2.03 and 3.89, respectively. Increased RR for these two cancer types were seen both after extended radiotherapy and after radiotherapy combined with chemotherapy. Studies of the time between treatment and secondary lung cancer indicated that the development of the new lung cancer could be partly treatment related, whereas the raised incidence of malignant melanoma may be related to the frequent health checks performed in patients with testicular cancer. Patients who had received extended radiotherapy were also at an increased risk of developing cancer of the stomach and of the colon. Three cases of acute leukaemia were observed more than 5 years after treatment, all of them in patients who had received abdominal radiotherapy only. It is concluded that patients apparently cured of a testicular cancer have an increased risk of developing a new treatment related non-germ cell malignancy, in particular lung cancer. The application of the extended radiotherapy or the combination of radiotherapy and chemotherapy containing alkylating drugs should be avoided in order to reduce this excess risk.