Brain Met Re-occurence - 1256482

4/26/13 - Brain met surgery to remove 1 1/4 inch tumor. One other smaller lesion and the tumor bed will be treated with radiation therapy beginning tomorrow (5 treatments). I will then begin my third line of chemo for my lung cancer which has now reared its ugly head for the third time.
Question: since I now have a "history" of brain mets does that mean my chances of re-occurence are greater? I know with all lung cancer brain mets is a possibility, I just wonder if I am now in a more likely group. Is there anything that can/should be done to reduce the risk?