Purpose: To assess the results of treatment and patterns of relapse in a contemporary group of patients with stage I testicular seminoma managed by adjuvant radiation therapy (RT) and surveillance.
Patients and methods: Between January 1981 and December 1991, 364 patients with stage I seminoma were treated at Princess Margaret Hospital. Of these, 194 were treated with adjuvant RT (92% received a dose of 25 Gy in 20 fractions for 4 weeks) and 172 were managed by surveillance. Two patients were included in this series twice--both had postorchiectomy RT for stage I disease, developed a contralateral seminoma, and were placed on surveillance and analyzed for outcome of both primary tumors. The median follow-up period for patients treated with adjuvant RT was 8.1 years (range, 0.2 to 12), and for patients managed by surveillance, it was 4.2 years (range, 0.6 to 10.1).
Results: The overall 5-year actuarial survival rate for all patients was 97%, and the cause-specific survival rate was 99.7%. Only one patient died of seminoma. Of 194 patients treated with RT, 11 have relapsed, with a 5-year relapse-free rate of 94.5%. Prognostic factors for relapse included histology, tunica invasion, spermatic cord involvement, and epididymal involvement. Twenty-seven patients developed disease progression on surveillance, which resulted in a 5-year progression-free rate of 81.9%. The only factor identified to predict progression on surveillance was age at diagnosis: patients aged < or = 34 years had a 26% risk of progression at 5 years, in contrast to a 10% risk of progression in those greater than 34 years of age.
Conclusion: The outcome of patients with stage I testicular seminoma is excellent, with only one of 364 patients (0.27%) dying of disease. In our experience, both a policy of adjuvant RT and of surveillance resulted in a high probability of cure. Our surveillance experience showed that four of five patients with stage I seminoma are cured with orchiectomy alone. The benefit of adjuvant RT was reflected in a decreased relapse rate. We have identified a number of prognostic factors for relapse in patients managed with both approaches, but further study of prognostic factors is required, particularly to identify patients at high risk of disease progression on surveillance.