Surgery for Stage IV Adenocarcinoma with SOLITARY metastasis to sternum? - 1271045

Hi:
My 68 year old mother in law was recently diagnosed with Stage IV NSCLC. She was diagnosed in March 2015 with a 4 cm tumor in her right upper lobe and only ONE solidary metastasis to the sternum, which is categorized as a hyper metabolic subtle sclerotic lesion on the PET scan.The sternum was never biopsied so no definitive diagnosis there but doctors felt confident enough that it was a metastasis. My mother in law is very healthy and active for her age. She has undergone five rounds of chemo (carbo, taxol, avastin regime) with minimal side effects and has remained active. The tumor has shrunk and is now 3.1 x 2.4 cm. The STERNAL lesion is now STABLE. There is NO NEW AREAS OF METASTASIS. I believe the plan is to do one more round of chemo (round six) and then do begin radiation on the tumor and bone. Given this information, would surgical removal of the primary tumor with radiation to the sternum (or possibly sternectomy) be an option? While I agreed with starting chemo to shrink the tumor, after six rounds, shrinkage of the tumor, and no new incidences, and in the absence of biopsy of sternum, I am wondering whether surgical removal would be a better option than radiation. ie.- Just remove the tumor instead of subjecting her to numerous rounds of radiation and agitating the tumor and disturbing the cancer cells all the while. I understand the stage IV diagnosis required systemic treatment initially, but to me, radiation of the tumor is targeting the tumor, which could be done by surgical removal. Of course, there may be risks to surgery that would have to be weighed against radiation. Just wanted another opinion.
Thanks for your response!