For patients with seminoma testicular cancer who are Stage II (positive retroperitoneal lymph nodes), what factors do you consider when choosing between radiation versus chemotherapy?

I usually look at the size of the retroperitoneal adenopathy, the age of the patient and the anticipated tolerance of chemotherapy. Disease > 3cm in the retroperitoneum is most often treated with chemotherapy. Less than 3 cm, it becomes a clinical judgement. Older patients probably have lower risk of developing secondary malignancies related to radiation and in a 50 year old with 2.5 cm disease, I likely would recommend therapeutic radiation therapy which should cure almost 90% of such patients. The challenge is that prior radiation probably increases risk of full dose chemotherapy with more myelosuppression and challenges with renal function. It is most reasonable to treat younger healthy patients with unequivocal stage IIA/B seminoma are ...