High Rate of Initial Treatment Failure in Patients with Primary Mediastinal B-Cell Lymphoma Treated with R-CHOP

• Published in: Blood 2011-11, Vol.118 (21), p.1601-1601
• Main Authors: Abramson, Jeremy S., Hellmann, Matthew D, Feng, Yang, Barnes, Jeffrey A., Takvorian, Tak, Toomey, Christiana E., Sheppard, Michael, Michaelson, James S., Neuberg, Donna, Hochberg, Ephraim P.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V118.21.1601.1601

Abstract 1601 Primary Mediastinal B-cell Lymphoma (PMBCL) is an uncommon variant of Diffuse Large B-cell Lymphoma (DLBCL). Given the rarity of this disease, data guiding management is extrapolated from DLBCL trials, or from small retrospective analyses limited to PMBCL. Prospective evaluation of R-CHOP in the MiNT trial showed excellent results in PMBCL, but this trial was limited to young low risk patients. We present the largest retrospective series to date of R-CHOP for PMBCL in all risk groups. We identified cases of PMBCL at our institution using a comprehensive clinicopathologic database derived from tumor registry data. Natural language processing software was used to search pathology reports for terms of “mediastinal lymphoma,” “mediastinal large cell lymphoma,” “mediastinal large B-cell lymphoma,” as well as “lymphoma” in mediastinal biopsy specimens. Cases were included if they met clinicopathologic criteria for PMBCL, defined as a large B-cell lymphoma with typical features for PMBCL presenting with a dominant anterior mediastinal mass. All patients had to have been treated with R-CHOP. Progression-free survival (PFS) and overall survival (OS) are calculated by the Kaplan-Meier method and univariate analysis is performed to assess predictors of outcome. Fifty-eight cases from 2000–2011 met inclusion criteria and are included in the analysis. The median age was 38 years (range 20–82) and 60% were male. Forty-four patients (76%) presented at limited Ann Arbor stage and 12 patients (21%) at advanced stage; presenting stage could not be discerned in 2 patients. Fifty-five percent of patients presented with mediastinal bulk ≥10cm in size; median size was 11cm (range 5–17cm). LDH was elevated at diagnosis in 60% of patients, normal in 21%, and unknown in 19%. By revised IPI score, 19% were low-risk (0 risk factors), 60% were intermediate risk (1–2 risk factors) and 12% were high-risk (≥3 risk factors). R-CHOP was given for a median of 6 cycles (range 1–8); 51 of 58 patients received 6 or 8 cycles. Among patients who achieved initial remission, 78% underwent consolidative radiotherapy and the remainder were observed after chemotherapy alone. The overall response rate was 81% (90%CI [71%–89%]) with 72% complete responses and 9% partial responses. Ten patients (17%) had primary refractory disease defined as progression on treatment or within 3 months of completion of therapy. Among 46 patients who achieved a response, 5 (11%) subsequently relapsed. Two p