I would seek a second opinion if there are any questions in your mind. Maybe they will know something better for your mom. Let us hear from her, best wishes.
Leon, I recommend for your mom to modify her diet. I have written about it here--apparently my mom is very lucky to not have had any relapse for over 6 years, had one just now and gets a lot of funny questions about "what happened in between these two ocurrences", namely, nothing. We are positive this is in great part, but not only, because of how she changed her diet (some of which is scientifically known to cause cancer, dairy issue etc.). Lots of literature available on it and survivors' stories most of which have certain nutritional aspects in common.
From the grinning cat.
Just to add: And yes, she had another abdominal abstruction as well, and had that taken out.Radiation is known to shrink tumors, but the side effects, like chemo, are so hard on the immune system, possibly harder than surgery, so as long as that is an option I would go for surgery and the food. We are much more strict now as she slacked considerably meantime, plus severe emotional hardship which seems to bring tumors on instantaneously almost,. Hope this helps and well wishes to your mom.