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 ( > or =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 > or =36 Gy was related to a longer OS, while the extension of the radiotherapy field did not modify outcome. No treatment-related 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.