Francesca,
especially with IMRT it is difficult to compare radiation effects because the extent of the irraduated tissue volume and location can vary greatly. This also means that the side effects are quite variable and depend on location/volume that is zapped. Depending on your particular case the volume may not be that big, on the other hand just because it is possible now you do not want to be too skimpy and miss stuff.
Perhaps this is a point to discuss with your docs: the extent of tissue they would need irradiate?

Markus