In patients with breast cancer, do you use bolus when boosting a chest wall scar or flap with electrons?

In terms of evidence basis for use/non-use of bolus generally in the setting of post-mastectomy chestwall radiotherapy (not limited to electron boost, noting that the use of post-mastectomy boost at all is a topic worthy of debate), here's what I found when I explored the same question a few years ago:

No difference in LC outcome, increased toxicity, one study suggesting concern for increased LF risk due to treatment interruption (higher in bolus group):

• Pittsburgh retrospective (n=106, 2005-2015) - Abel et al., PMID 28395915
• Sydney (Australia) retrospective (n=254, 1993-2003) - Tieu et al., PMID 21362579
• Harvard group retrospective (univariate factor, buried within text) - Uematsu et al., PMID 8478226

This being stated, during my time on st...

As a routine, I don’t use bolus for boost and use 6 mev electrons which gives 80% plus dose to skin.

Also we don’t boost anyone with reconstruction unless positive margin. We don’t use reaction to guide bolus because we use hypofractionation and since it takes time to develop reaction (peak happens weeks after RT done) it can be misleading.

Skin reaction at the time of boost is considered. Otherwise, I make decisions based on the Eclipse plan sum as to the need for bolus and how much, shape of chest wall, etc. There is no one size fits all and I prefer to plan everything in Eclipse vs clinical. However, I don’t routinely boost and esp not with TEs. The plastic surgeons typically are reluctant to deflate them, to say the least, so it makes e-boost practically impossible, but even if they agree, the TEs are not fully deflated and flat so really only would attempt if R1 and after asking the surgeon to help me localize where that margin is.

There is no good evidence to suggest that a chest wall boost, with or without bolus added to PMRT promotes local control or increased survival any better than PMRT without boost.

None.