Radiation while a seroma is healing

Seattle10

My aunt had a mastectomy and a number of lymph nodes removed. She has developed a seroma that doesn't seem to be healing but the surgeon wants to go ahead with radiation treatments anyway. She is not only concerned that the seroma is not healing but is now concerned that the radiation might affect the healing process of the seroma. Can anyone give us some insight on this - whether or not it's okay to have radiation while the seroma is still healing?

Sincerely,

Randy