How do you approach treatment of a non-seminoma brain metastasis with a partial response to chemotherapy?

Assuming one rules out leptomeningeal spread, I would still prefer to treat the non-seminoma brain metastasis with either stereotactic radiosurgery (18 Gy in one fraction if max. diameter is less than 2 cm), or fractionated stereotactic radiation (8 to 9 Gy per fraction x 3 if the metastasis is larg...