Consolidation radiotherapy to bulky or semibulky lesions in the management of stage III-IV diffuse large B cell lymphomas

Background: To assess the impact on survival of consolidation radiotherapy to bulky or semibulky lesions in patients with advanced diffuse large B cell lymphoma (DLCL) in complete remission after primary chemotherapy. Patients and Methods: Ninety-four patients with stage III-IV DLCL and bulky (≥ 10 cm) or semibulky lesions (6-9 cm) in complete remission after primary chemotherapy were reviewed. Forty patients received consolidation radiotherapy to bulky (n = 20) or semibulky lesions (n = 20), while 54 (18 with bulky disease) did not. Twenty-eight patients were irradiated to the involved field and 12 to the extended field with a dose of 30-46 Gy. Results: In patients with bulky disease, consolidation radiotherapy prevented relapses involving exclusively the bulky area, prolonged time to relapse (TTR) (median 41+ vs. 18 months; p = 0.05) and improved 5-year overall survival (OS) (73 vs. 57%; p = 0.05). Consolidation radiotherapy reduced relapses within the semibulky area, prolonged TTR (median 26+ vs. 20 months; p = 0.01) and improved 5-year OS (59 vs. 41%; p = 0.09) also in patients with semibulky lesions. Multivariate analyses confirmed the independent association between consolidation radiotherapy and survival, and showed that a dose ≥ 36 Gy was related to a longer OS, while the extension of the radiotherapy field did not modify outcome. No treatment-reiated deaths were observed. Four patients developed a second malignancy, none of whom had undergone consolidation radiotherapy. Conclusions: Consolidation radiotherapy to bulky or semibulky lesions significantly improved the outcome in patients with advanced DLCL in complete remission after primary chemotherapy. Involved-field irradiation with 36-45 Gy made a prolonged disease control possible without either lethal toxicity or a higher incidence of second malignancies. Copyright (C) 2000 S. Karger AG, Basel.