Outcomes of Patients with Transformed Diffuse Large B-Cell Lymphoma (DLBCL).

PURPOSE/OBJECTIVE(S): There is limited data regarding the results of treating transformed Diffuse Large B-Cell Lymphoma, including the influence of radiation therapy on their overall prognosis. Thus, we aimed to investigate the clinical outcomes of transformed DLBCL patients treated at a single institution.

MATERIALS/METHODS: We reviewed clinical features and outcomes of 27 patients with biopsy confirmed transformed Diffuse Large B-cell Lymphoma (DLBCL) treated at a single institution from 2005 and 2014. Response to therapy was based on the Deauville criteria. Kaplan-Meier method was used to estimate time to event outcomes and compared using log-rank tests. Associations between local recurrence and relevant clinical variables were analyzed using logistic regression.

RESULTS: The median age of patients was 63 (43-84). Eleven patients (40.7%) presented with bulky disease. The majority of patients (n = 16, 59.3%) had the activated B-cell (ABC) subtype, while 11 (40.7%) patients had germinal center B-cell (GCB) subtype. Most of the patients had early-stage disease 19 (70.4%). Double- and triple-hit expression was noted in 6 (22.2%) and 3 (11.1%) patients, respectively. The median international prognostic index (IPI) was 2. Median follow up was 37 months (range 2-168). Twelve (44.4%) patients received consolidative RT after systemic therapy with a median dose of 36 Gy (30-45). At 72 months, our RT cohort had an overall survival (OS), relapse-free survival (RFS) and local control (LC) rates of 63%, 64% and 81%, respectively. The OS did not differ between patients that received RT compared to those who did not (p = 0.124), although RT conferred statistically significant improvement in OS on MVA (HR 0.07; 95% CI, 0.007 to 0.718; p = 0.025). In the group that received RT, local control was worse among patients with double or triple-hit disease (p = 0.034).

CONCLUSION: Patients with transformed Diffuse Large B-cell Lymphoma treated with RT may have better outcomes than patients who did not receive RT. Presence of translocation (double-hit and/or triple-hit lymphomas) was significantly associated with worse local control in our RT cohort.