By localized I'm assuming you're referring to stage I/II disease. I typically like to avoid radiation to the chest area, particularly in younger and female patients, to avoid predisposing them to the risk of radiation induced complications in these areas. Therefore, for most patients I use the RATHL adapted approach of giving 2 cycles of ABVD and then if favorable response (Deauville 1-3) will drop the bleomycin and complete 4 additional cycles with AVD. For patients who have localized disease outside of the chest, or occasionally older patients, I will consider doing 2 additional cycle of ABVD and then ISRT. For patients with poor response (deauville 4-5) NCCN guidelines recommend switching to BEACOPP but in our center's experience if patients have significant progression of disease with ABVD they often don't respond well to BEACOPP and so we will switch them to a PD-1 containing regimen and then consider autologous stem cell transplant.