Bolus affect.

Top Line: Have you ever asked why someone decides to use chest wall bolus during post-mastectomy radiation (PMRT)?

The Study: Answers might include (1) observed chest wall recurrences have involved the skin and/or (2) that’s how it’s always been done. And while neither of these statements are wrong, they don’t mean we have great data that chest wall bolus helps. In fact, ESTRO consensus guidelines recommend against the routine use of chest wall bolus during PMRT. We now have…wait for it…a prospective randomized trial on the subject. It’s unclear why it’s taken us 60 years to get here, but here we are nonetheless. Enrollees were stratified by presence of skin involvement, and those with (n=24) were randomized to daily versus every other day bolus and those without (n=34) to every other day bolus versus no bolus. Of note, 59% underwent 3D-planning, 41% 2D-planning, and 0% IMRT planning. In the end, there was no difference in rate of local control at 5 years either way: 96% without skin involvement and 91% with skin involvement regardless of bolus practice.

TBL: This small randomized trial supports the idea that the routine use of bolus may not be necessary when delivering PMRT in patients with no skin involvement. | Sapienza, ASTRO 2022