Rapid symptomatic and metabolic response to emergency radiotherapy in a critically ill patient with primary cardiac lymphoma: a multidisciplinary case report

Primary cardiac lymphoma (PCL), an exceptionally rare and aggressive malignancy with median survival under one month, often presents with contraindications to first-line chemotherapy in critically ill patients. We report a 66-year-old woman with acute heart failure, pulmonary embolism, and ECOG performance status 4, diagnosed with right atrial diffuse large B-cell lymphoma (76 × 75 mm, SUVmax = 29.1). Due to chemotherapy contraindications, emergency radiotherapy (18 Gy/10 fractions) was initiated. Within five fractions, significant symptomatic improvement occurred with resolution of dyspnea and edema, accompanied by improved oxygenation (SpO₂ 86%→95%) and ECOG status (4→3). Post-treatment PET/CT demonstrated a profound metabolic response (SUVmax = 2.9-3.6), enabling successful transition to systemic chemotherapy. This case underscores emergency radiotherapy as an effective bridge therapy for critically ill PCL patients, facilitated by multidisciplinary coordination.