Is increased abdominal fat common post cancer treatment?

I am approx 1 year post active treatment ie Mastectomy, Chemo and Radiotherapy.
Now on Aromatase Inhibitors for 5-10 years.
I would like to lose weight, but my weight is stable, and has been for about 1 year.
I feel that in the last year I have more abdominal fat ie without weight gain. More of a change in shape.
Has anyone else observed this, for themselves?
I am now 63, maybe an age thing?