How well does left chest wall electron chest wall RT compare with IMRT with with respect to heart and lung radiation doses?  

The acute skin toxicity is high, as well as the late telangiectasias. There can also be substantial variation in the skin surface contour of the patient, so really only patients without reconstruction and relatively ‘flat’ profile are suitable. Some have mitigated that by building custom...

There is a nice literature demonstrating that chest-wall electrons are a viable tx approach for PMRT (e.g. UFla has a nice series; Feigenberg et al., PMID 12788177). Like many things, the more you do it, the better you get (so maybe someone from UF can chime in). I have done this maybe 50 times...

It may offer heart and lung dose advantages in some scenarios but heterogeneous has dose distribution and most importantly, skin toxicity is also higher because of surface dose to circumvent that we do sometimes use medial electron matched to lateral photon tangent.

I sometimes use an electron field to cover as much of the anterior chest wall as possible and then match that with a lateral photon field with bolus. The photon field can be extended superiorly to cover the axilla and SCF if needed with a central block over the electron field.