Treatment and clinical management of primary mediastinal large B-cell lymphoma with sclerosis: MACOP-B regimen and mediastinal radiotherapy monitored by (67)Gallium scan in 50 patients

To evaluate the efficacy of a combined modality treatment (MACOP-B plus mediastinal radiotherapy) and the advantages of Gallium-67-citrate single-photon emission ((GaSPECT)-Ga-67) 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 (GaSPECT)-Ga-67 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 (GaSPECT)-Ga-67 and negative CT scan relapsed, as against 0/21 (0%) with negative (GaSPECT)-Ga-67 and CT scan. Twenty-one patients had a positive CT scan: of these, the 4 with positive (GaSPECT)-Ga-67 all progressed, whereas there were no relapses among the 17 with negative (GaSPECT)-Ga-67. After radiotherapy, there was a decrease of positive CT (from 33 to 21 cases) and of positive (GaSPECT)-Ga-67 (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, (GaSPECT)-Ga-67 should be considered the imaging technique of choice at least in patients who show CT positivity. (C) 1999 by The American Society of Hematology.