I will post my two cents here. Take my advice/comments with a grain of salt, since I am not a medical oncologist or radiologist.
Having said that, a lot of board members here have had SBRT (I am assuming this is the kind you will have) on their lung mets. This seems to have been very successful, and they seem to have reached NED.
There are a few disadvantages of radiation. I'll list a few here. Any sort of radiation, while it may have beneficial short term effects (stopping the growth of METS, or even frying them to a crisp), can have long term repercussions. Of course, as a Stage IV, reaching many years of long life is our eventual goal, so this is sort of a chicken and an egg type of thing. Any sort of radiation, even focused radiation can hit other areas of your body that may not be intended. If your mets are on your lung close to your heart, some can of the targeted radiation can leak into the heart. As with any cancer treatment, you have to weigh all your options.
If you are otherwise healthy and strong, I would suggest the surgical route. Consult with a lung specialist, and you can potentially have them wedge it out (using conventional surgical techniques). There are a few doctors in europe that operate on pulmonary modules with a laser.
There is also the infamous RFA technique, which basically heats up small lung modules and frys up the surrouding tissue so that the tumor dies. There is also a cryoablation technique that can also be used to freeze the tumor and destroy it.
3/2015 - Rectal Cancer @ 26yr old.
5/2015 - Clinical Trial (FOLFOX Only)
9/2015 - LAR with TME (Stage IIIB, RC) w/ Loop Ileostomy
2/2016 - Ileostomy Reversal
5/2016 - Stage IVb