Symptomatic pneumonitis, a subacute toxicity, has an incidence of 17% to 24% (≥grade 2) even with IMRT. A total of 85 patients with r/r lymphoma (66% HL, 34% NHL; 46% primary chemorefractory) received thoracic PBT in the consolidation (45%) or salvage (54%) setting.  With a median follow-up of 26.3 months among living patients, 11 patients developed symptomatic (grade 2) pneumonitis (12.8%). No grade 3 or higher pneumonitis was observed. The study concluded that PBT for relapsed/refractory lymphoma was associated with favorable rates of pneumonitis compared with historical controls.