Treatment and Clinical Management of Primary Mediastinal Large B-Cell Lymphoma With Sclerosis: MACOP-B Regimen and Mediastinal Radiotherapy Monitored by 67Gallium Scan in 50 Patients

Abstract

To evaluate the efficacy of a combined modality treatment (MACOP-B plus mediastinal radiotherapy) and the advantages of Gallium-67-citrate single-photon emission (67GaSPECT) over computed tomography (CT) for restaging in patients with primary mediastinal large B-cell lymphoma (PMLBCL) with sclerosis. Between 1989 and 1998, 50 previously untreated patients with PMLBCL with sclerosis (70% with bulky mass) were treated with MACOP-B regimen plus mediastinal radiotherapy. The radiologic clinical stage with evaluation of tumor size included CT and 67GaSPECT at diagnosis, after chemotherapy, and after radiotherapy. Forty-three patients (86%) achieved a complete response and 7 were nonresponders to treatment. For the imaging evaluation, only 47 patients were evaluable because 3 had disease progression during chemotherapy. After treatment, 3/5 (60%) patients with positive 67GaSPECT and negative CT scan relapsed, as against 0/21 (0%) with negative 67GaSPECT and CT scan. Twenty-one patients had a positive CT scan: of these, the 4 with positive 67GaSPECT all progressed, whereas there were no relapses among the 17 with negative 67GaSPECT. After radiotherapy, there was a decrease of positive CT (from 33 to 21 cases) and of positive 67GaSPECT (from 31 to 9 cases). Relapse-free survival rate was 93% at 96 months (median 39 months). In patients with PMLBCL with sclerosis, MACOP-B plus radiation therapy is a very useful first-line treatment and radiation therapy may play an important role. As regards restaging, 67GaSPECT should be considered the imaging technique of choice at least in patients who show CT positivity.