MACOP-B and Involved-Field Radiotherapy Is an Effective and Safe Therapy for Primary Mediastinal Large B Cell Lymphoma

Purpose To report the clinical findings and long-term results of front-line, third-generation MACOP-B (methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin) chemotherapy and mediastinal involved-field radiotherapy (IFRT) in 85 consecutive, previously untreated patients with primary mediastinal large B cell lymphoma (PMLBCL) diagnosed and managed at a single institution. Methods and Materials Between 1991 and April 2004, 92 consecutive, untreated patients with PMLBCL were treated at our institution. The median age was 33 years (range, 15–61 years), 46 patients (50%) showed a mediastinal syndrome at onset; 52 patients (57%) showed a low/low–intermediate (0 to 1) and 40 patients (43%) an intermediate–high/high (2 to 3) International Prognostic Index (IPI) score. Eighty-five patients were treated with standard chemotherapy (MACOP-B), and 80 underwent mediastinal IFRT at a dose of 30–36 Gy. Results After a MACOP-B regimen, the overall response rate was 87% and the partial response rate 9%. After chemotherapy,67 Ga scintigraphy/positron emission tomography results were positive in 43 of 52 patients (83%), whereas after IFRT 11 of 52 patients (21%) remained positive ( p < 0.0001). After a median follow-up of 81 months (range, 2–196 months), progression or relapse was observed in 15 of 84 patients (18%). The projected 5-year overall survival and progression-free survival rates were 87% and 81%, respectively. The 5-year overall survival and progression-free survival rates were better for patients with an IPI of 0 to 1 than for those with an IPI of 2 to 3 (96% vs. 73% [ p = 0.002] and 90% vs. 67% [ p = 0.007], respectively). Conclusions Combined-modality treatment with intensive chemotherapy plus mediastinal IFRT induces high response and lymphoma-free survival rates. Involved-field RT plays an important role in inducing negative results on67 Ga scintigraphy/positron emission tomography in patients responsive to chemotherapy.