Dosimetric and Clinical Outcomes of Involved-Field Intensity-Modulated Radiotherapy After Chemotherapy for Early-Stage Hodgkin’s Lymphoma With Mediastinal Involvement

Abstract

To evaluate the dosimetric and clinical outcomes of involved-field intensity-modulated radiotherapy (IF-IMRT) for patients with early-stage Hodgkin's lymphoma (HL) with mediastinal involvement. Fifty-two patients with early-stage HL that involved the mediastinum were reviewed. Eight patients had Stage I disease, and 44 patients had Stage II disease. Twenty-three patients (44%) presented with a bulky mediastinum, whereas 42 patients (81%) had involvement of both the mediastinum and either cervical or axillary nodes. All patients received combination chemotherapy followed by IF-IMRT. The prescribed radiation dose was 30-40 Gy. The dose-volume histograms of the target volume and critical normal structures were evaluated. The median mean dose to the primary involved regions (planning target volume, PTV1) and boost area (PTV2) was 37.5 Gy and 42.1 Gy, respectively. Only 0.4% and 1.3% of the PTV1 and 0.1% and 0.5% of the PTV2 received less than 90% and 95% of the prescribed dose, indicating excellent PTV coverage. The median mean lung dose and V20 to the lungs were 13.8 Gy and 25.9%, respectively. The 3-year overall survival, local control, and progression-free survival rates were 100%, 97.9%, and 96%, respectively. No Grade 4 or 5 acute or late toxicities were reported. Despite the large target volume, IF-IMRT gave excellent dose coverage and a favorable prognosis, with mild toxicity in patients with early-stage mediastinal HL.