When using hypofractionated whole breast radiotherapy with a simultaneous integrated boost to the lumpectomy cavity, what IGRT strategy do you use?  

My preference is CBCT daily and matched to clips/cavity. Our practice also does SGRT for all patients (tattoo-less clinic); however, that is not routinely reimbursed. If treating like RTOG 1005 (48/40 in 15 Fx) and approved for IMRT, will get approved for IGRT.

I could be mistaken, but my recollection of the RTOG 1005 protocol from the publication and my own few patients enrolled was that the toxicity was significant without any benefit in terms of local control compared to kinder, gentler techniques.