To print: Select File and then Print from your browser's menu --------------------------------------------------------------------------------------- Title: Outcome of Primary Mediastinal Large B-Cell Lymphoma: Presented at ICML URL: http://www.pslgroup.com/dg/24E532.htm Doctor's Guide June 17, 2005
By Chris Berrie LUGANO, SWITZERLAND -- June 17, 2005 -- Dose-intensive chemotherapy treatment regimens that do not need to be associated with involved-field radiotherapy (IF-RT) can promote excellent survival rates and low levels of relapse for patients with primary mediastinal large B-cell lymphoma (PMBCL). Kerry J Savage, MD, principal investigator and medical oncologist, department of medical oncology, British Columbia Cancer Agency (BCCA), Vancouver, British Columbia, Canada, presented these findings, from a single-institution, population-based, retrospective study, here on June 10th at the 9th International Conference on Malignant Lymphoma (ICML). "Since the 1990s, PMBCL has been recognised as a distinct subtype of diffuse large B-cell lymphoma (DLBCL) based on unique clinical and pathological features," Dr. Savage explained. Patients with PMBCL are predominantly women between the ages of 30 and 40 years who present with prominent mediastinal masses with or without intrathoracic disease extension. The first aim of Dr. Savage's study was to evaluate the outcome and long-term natural history of PMBCL in patients treated according to the Lymphoma Tumour Group (LYTG) guidelines of the BCCA, and to understand the survival benefits of chemotherapy and postchemotherapy IF-RT. Researchers extracted a total of 153 patients (median age, 37 years; female, 44%) from the BCCA lymphoma electronic database. These patients presented from 1980 to 2003 with PMBCL according to the current Revised European-American Classification of Lymphoid Neoplasms (REAL)/World Health Organisation classifications. The majority of patients presented with stage I/II (74%), bulky mediastinal disease (75%) with intrathoracic extension (76%), and elevated lactate dehydrogenase (LDH) levels (77%). Most of the patients had an intermediate risk according to their age-adjusted International Prognostic Index scores (aaIPI 1/2, 75%). Chemotherapy was based on era-specific guidelines: 1980-1992, MACOPB*/VACOPB**; 1992-1998, CHOP-type***; 2001-2003, CHOPR****. Limited-stage PMBCL received brief chemotherapy followed by IF-RT, while from 1998, all advanced-stage patients received IF-RT at a dose of 35 Gy following their chemotherapy (LYTG recommendation). The 5-year rates of overall survival (OS) and progression-free survival (PFS) of the entire cohort were 75% and 70%, respectively. When calculated according to chemotherapy received by subjects who were younger than 65 years of age, the only significant difference in 5-year OS was seen between MACOPB/VACOPB (n = 47) and CHOP-type (n = 67) (87% vs. 71%; P =.016). This was probably due to the smaller number of patients and the short time of treatment use for CHOPR (n = 19; 5-year OS, 82%), Dr. Savage said. Further analysis of baseline characteristics of the MACOPB/VACOPB versus CHOP-type cohorts showed that the latter contained significantly more patients with B symptoms (56% vs. 30%; P =.007), PS >1 (46% vs. 21%; P =.007), an elevated LDH that was 2x ULN (43% vs. 19%; P =.009), and more had received radiation as part of their primary therapy (47% vs. 19%; P =.003). Evaluation of the impact of various prognostic factors on 5-year OS at the univariate level showed significance for treatment type (CHOP vs. MACOPB/VACOPB; P =.02), PS >1 (P =.006), LDH >2x ULN (P =.025), and age >40 years (P =.003). Only the first 2 of these factors remained significant after multivariate analysis (P =.09, P =.01, respectively). For IF-RT, a pre- (n = 103) versus post- (n = 50) policy change analysis showed that routine IF-RT is not associated with improvements in progression-free survival (PFS) in these PMBCL patients. Of the 9 refractory PMBCL patients eligible for high-dose chemotherapy and stem cell transplantation (HDC SCT), 7 proved to be chemoresistant, and the 2 who were chemosensitive relapsed and died from the lymphoma. Among the 23 relapsed patients who were eligible for HDC SCT, 7 were chemoresistant and 12 ultimately went on to receive HDC SCT and showed a 40% 5-year OS and a 20% 10-year. "This population-based, retrospective study has shown that PMBCL patients have a favourable outcome with a 5-year overall survival of 75% and rare relapses after 2 years, further highlighting the difference between this disease and DLBCL," said Dr. Savage. She also indicated that while a proportion of relapsed PMBCL patients can be salvaged with HDC SCT and routine IF-RT is not associated with improved PFS, the full significance of rituximab within the CHOPR regimen remains to be seen. * MACOPB: methotrexate, adriamycin, cyclophosphamide, vincristine, prednisone, bleomycin ** VACOPB: etoposide, adriamycin, cyclophosphamide, vincristine, prednisone, bleomycin *** CHOP: cyclophosphamide, doxorubicin, vincristine, prednisolone *** CHOPR: CHOP plus rituximab [Study title: Outcome of Primary Mediastinal Large B-Cell Lymphoma in a Single Institution: The British Columbia Experience. Abstract 073] --------------------------------------------------------------------------------------------- Copyright © 1999 P\S\L Consulting Group Inc. All rights reserved. Republication or redistribution of P\S\L content is expressly prohibited without the prior written consent of P\S\L. 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