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 a...

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 develo...

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 an...

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.