Combination carboplatin and radiotherapy in the management of stage II testicular seminoma: comparison with radiotherapy treatment alone.

PURPOSE: To assess the results of treatment in 33 patients with stage IIA/B seminoma who were treated with carboplatin and radiotherapy (RT) between January 1989 and December 1996. PATIENTS AND METHODS: Thirty patients received single course single agent carboplatin (400 mg/m2 or area under curve (AUC 7), two patients received two courses carboplatin, and one patient received single course carboplatin and etoposide, all 4-6 weeks prior to infra-diaphragmatic RT. Results were retrospectively compared with those obtained for 80 patients treated from 1970 to 1998 with radiotherapy alone. RESULTS: There was minimal toxicity associated with the use of carboplatin prior to RT. With a median follow-up of 4 years (range 2-70 months) 2/33 patients treated with chemotherapy and RT have relapsed, 5-year relapse free survival (RFS) = 96.9% (95% confidence interval (CI) 72.9-99.4%), and one patient has died of progressive disease, 5-year overall survival (OS) = 96.7%. With a median follow-up of 11.2 years (range 6 months to 25.8 years) 15/80 patients treated with RT alone have relapsed, 5-year RFS = 80.7% (95% CI 70.1-87.9%), including 13/61 patients treated with infra-diaphragmatic RT, 5-year RFS = 77.9%, and 2/19 treated with additional supra-diaphragmatic RT, 5-year RFS = 89.5% (P = 0.277). Eleven out of 80 patients have died, 5-year OS = 94.7%. For stage IIA, 1/14 patients treated with chemotherapy and RT have relapsed, 5-year RFS = 92.3%, compared with 5/34 treated with infra-diaphragmatic RT alone 5-year, RFS = 84.9% (P = 0.527). For stage IIB, 1/19 patients relapsed (at 69 months) following chemotherapy and RT (5-year RFS = 100%), whereas 8/27 relapsed following infra-diaphragmatic RT alone, 5-year RFS = 69.4% (P = 0.0595). CONCLUSION: Infradiaphragmatic RT alone cures the majority of patients with stage II seminoma, but the relapse rate remains high particularly for patients with stage IIB disease. As compared with historical controls, carboplatin with RT appears to reduce the relapse rate in stage II seminoma with minimal additional toxicity and the results approach statistical significance for stage IIB patients. Confirmation would require a phase III randomized comparison.