Long-term outcomes of radiotherapy for stage II testicular seminoma–the Mayo Clinic experience

ObjectivesTo report long-term outcomes of patients with stage II testicular seminoma treated with radiotherapy (RT).Materials and methodsA retrospective review was performed of 52 patients who received megavoltage RT for stage II testicular seminoma at Mayo Clinic between 1974 and 2007. Forty-eight patients (92%) had computed tomography staging. Overall survival (OS), relapse-free survival (RFS), and cause-specific survival (CSS) were determined using the Kaplan-Meier method. Major cardiac event (MCE) was defined as myocardial infarction, coronary artery bypass grafting or stenting, or valve replacement. Second malignancy (SM) was defined as biopsy-confirmed malignancy occurring in the RT field.ResultsThe median patient age at diagnosis was 36 years. Stage was IIA (n = 24), IIB (n = 7), IIC (n = 17), and II not otherwise specified (NOS, n = 4). The median infradiaphragmatic RT dose was 30.7 Gy. Twenty-six patients (50%) received prophylactic mediastinal/supraclavicular (MSCV) RT. The median follow-up was 19 years. Estimates of OS, RFS, and CSS were 94%, 80%, and 96% at 10 years, and 83%, 72%, and 96% at 20 years, respectively. RFS at 10 years for stage IIA, IIB, IIC, and II NOS were 83%, 54%, 81%, and 100%, respectively (log-rank P = 0.21). Ten patients (19%) experienced disease relapse in the MSCV region (n = 7), para-aortic lymph nodes (n = 1), lung (n = 1), or peritoneal cavity (n = 1). Eight patients were successfully salvaged with chemotherapy and/or surgery, while 2 died of seminoma. Risk of MSCV relapse was significantly lower in patients who received MSCV RT vs. those who did not (10-year estimates: 4% vs. 21%, respectively, log-rank P = 0.01). MCE occurred in 10 patients (19%) at a median of 18 years (range 7–30) after RT. SM occurred in 5 patients (10%) at a median of 27 years (range 20–34) after RT.ConclusionsIn patients with stage II testicular seminoma treated with RT, relapse in the irradiated site was uncommon. Infradiaphragmatic RT alone was associated with a significant risk of MSCV failure. Most MCE and SM events occurred more than 20 years after RT, highlighting the importance of vigilant long-term follow-up.