How would you treat oligoprogressive metastatic GIST to the liver with a single enlarging liver lesion while on imatinib and no other evidence of active disease, where surgery and RFA are not possible?

Please refer to my answer for "Adjuvant RT in GIST" in the Sarcoma section for complete details, but as relative to this question:

In the palliative setting, I have radiated a handful of GIST patients who either had painful bone mets or a tumor of the liver with limited other options. If you review ...