Radiotherapy versus carboplatin for Stage I seminoma: Updated analysis of the MRC/EORTC randomized trial (ISRCTN27163214)
Seminoma (the most common type of testicular cancer) has traditionally been treated with orchiectomy followed by radiation therapy. Follow-up of these patients found that the radiation therapy resulted in higher risk of mortality, secondary cancers and cardiac issues. Seminomas are known to be quite sensitive to platinum chemotherapy agents. Therefore, this study compared 1 cycle of carboplatin to radiation therapy in stage I seminomas following orchiectomy.
1477 patients were randomly assigned to receive radiation or carboplatin after surgery. This report is based on 6.5 years follow up. There was no significant difference in recurrence-free survival between the groups. There was, however, a significant difference in the rate of 2 nd primary germ cell tumors (GCT). There were 2 (0.3%) cases in the carboplatin group (C) and 15 (1.7%) in the radiation therapy (RT) group.
As for side effects, patients were scored based on percentage of patients able to work at 4 weeks and 12 weeks. There was a significant difference at week 4 between C and RT, with 19% of carboplatin patients unable to do normal work vs. 38% unable to in the radiation group. However, this difference was not present at 12 weeks, at which time the majority of patients in both arms were able to function normally. There was increased grade 2 and 3 thrombocytopenia in the C group compared to the RT group. These results tell us that carboplatin is an effective alternative to radiation therapy for stage I seminomas and should be considered in this population. Longer follow up will look further at secondary cancers and cardiac problems, which may be possible in either group.