Five for all.
Top Line: In keeping with recent themes, let’s explore 5-fraction stereotactic body radiation (SBRT) for mediastinal and hilar nodal mets.
The Study: This is a site where ablative radiation doses should give pause given the high-stakes real estate. Here is a retrospective look at 5-fraction SBRT (median dose 35 Gy, range 30-50 Gy) for 84 mediastinal (63%) / hilar (37%) oligomets (median size 2 cm) in 52 patients treated at the University of Toronto. For almost all patients, systemic therapy was held for SBRT. Grade 3+ toxicity occurred in 7 patients (11.5%), including one grade 5 radiation pneumonitis—this last patient also received simultaneous SBRT to a parenchymal lung lesion. However, this toxicity should be viewed in the context of two-thirds of patients not requiring a change in systemic therapy for at least a year and nearly half not requiring a change in systemic therapy for two years. The reason for this is two-fold: (1) an excellent local control rate of 91% at two years in (2) an appropriately selected population.
TBL: In carefully selected patients, moderate-dose SBRT might be a safe and effective treatment option for mediastinal oligomets. | Shahi, ASTRO 2020