Hi, breast VMAT plans. 3D plans are here to say low-dose spill does (maybe? sometimes?) matter. A Chinese retrospective secondary analysis of 607 trial enrollees receiving hypofractionated post-mastectomy radiation describes interesting trends in post-radiation lymphopenia. Interestingly, 20% of enrollees experienced grade 3+ lymphopenia (<500/mm3). Lymphocyte nadir was typically upon treatment completion, started to recover by one week out, and returned to baseline one year out. Most interesting, IMRT techniques were associated with significantly lower lymphocyte nadirs, presumably due to larger regions of low-dose spill. The question is whether lymphopenia has any clinically meaningful impact in this setting and whether an effect outweighs other important OAR benefits from IMRT? | Zhao, Adv Radiat Oncol 2025
