Purpose: A retrospective study was performed to define clinical characteristics and therapeutic outcome for patients with large-cell and immunoblastic lymphoma of the mediastinum.
Patients and methods: Fifty-seven patients who presented with primary, mediastinal large-cell and immunoblastic lymphoma were retrospectively studied to determine initial sites of disease, radiologic characteristics, treatment, outcome, and factors that have prognostic significance for progression-free and overall survival.
Results: Fifty-six of the 57 patients had disease that was confined to sites above the diaphragm. Bulky disease and extensive intrathoracic infiltration were common in these patients. All patients were treated with intensive chemotherapy regimens, and 44% of patients received chest irradiation. The overall 5-year survival by Kaplan-Meier estimation was 50% with a freedom-from-relapse rate of 45%. Predictors of disease relapse after chemotherapy included the presence of a pleural effusion (P = .015), a number of involved extranodal sites (P < .01), and a lactic dehydrogenase (LDH) ratio > 3.0 (LDH value/upper limit of assay; P = .04) as well as an incomplete treatment response as evidenced by residual mass on chest radiograph (P = .02) or persistent gallium 67 avidity (P = .01) after chemotherapy. Predictors of decreased survival included the presence of pleural effusion (P = .001), the number of involved extranodal sites (P = .022), and a positive posttreatment 67Ga scan (P = .027).
Conclusion: Patients with primary mediastinal large-cell and immunoblastic lymphoma have an approximate 50% chance of surviving disease-free after initial therapy. The presence of pleural effusion at presentation was associated with an extremely poor outcome. Bulk disease per se was a negative predictive factor only in patients without pleural effusions when compared with patients who did not have bulk disease. In addition, all patients with involvement of two or more extranodal sites relapsed when treated with standard chemotherapy.