Would you omit a lumpectomy boost in a younger patient (<50 y) with a primary tumor that is otherwise favorable?  

This is certainly an evolving area, but I do routinely offer boost solely based on younger age (< 50 or < 40) in patients with otherwise favorable features (ex. T1N0 ER+/PR+/HER2-).

This is a great question worthy of further study. It's important to note that in the EORTC boost trial, assessment of margins for DCIS was not required. In addition, premenopausal patients did not receive endocrine therapy. The emerging data suggest that biology is key in young and older patients. I...

No.

As more data emerges from the genomic test and local control we may be guided by risk category to decide boost or not in ER-positive breast cancer in < 50 years.

Several years ago there was a retrospective review of the Whelan AFWBRT Study which did not include a boost.  The UToronto-Sunnybrook reviewed actual treatments of DCIS patients enrolled in the protocol and found some patients did receive a boost even though the protocol did not allow it. I th...