Primary mediastinal large B-cell lymphoma (PMBL) represents a distinct entity with unique clinicopathologic features similar to nodular sclerosis subtype of classical Hodgkin’s lymphoma.1 It was formally established as a distinct subtype of diffuse large B-cell lymphoma (DLBCL) in the European, American, and the World Health Organization classification of lymphoid neoplasms.2 It represents less than 3% of all non-Hodgkin lymphoma (NHL) with a propensity to affect young adults.1,2
The major challenge in the management of PMBL is that the initial therapy is critical since salvage therapy for recurrence or progressive disease is of limited efficacy.2 However, the balance between treating with the highest possible cure regimen and minimizing long-term morbidity in this young population may not always be achievable. Many chemotherapeutic regimens such as cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-type regimens have been used to treat PMBP but with poor results.2
Emerging evidence suggest that dose-intensified therapy using MACOP-B (methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin) or VACOP-B (etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin) may be superior to CHOP-type regimen.1,2 In addition, dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, and hydroxydaunorubicin (DA-EPOCH) was evaluated in previous trials in patients with PMBCL with promising results.1
A recent phase-II prospective study, funded by the National Cancer Institute (NCI)3, evaluated the role of infusional dose-adjusted DA-EPOCH with rituximab (DA-EPOCH-R) and filgrastim, without radiotherapy, in 51 young men and women, median age of 30 years (range, 19 to 52) with untreated PMBL. Patients received the regimen for 6 to 8 cycles of treatment. This regimen provided a 93% event-free survival rate and a 97% overall survival rate during a median of 5 years of follow-up with no late morbidity or cardiac toxicity in any patient. Complete remission was sustained in 49 patients who received DA-EPOCH-R alone after follow-up ranging from 10 months to 14 years.
Authors concluded that therapy with DA-EPOCH-R obviated the need for radiotherapy in patients with PMBL and provided an alternative and effective treatment modality for the disease. DA-EPOCH-R regimen seems to offer a new hope for young people with PMBL. Perhaps the future will tell us more about this regimen.
1. Savage KJ. Primary Mediastinal Large B-Cell Lymphoma. Oncologist. 2006;11(5):488-495.
2. Johnson PW, Davies AJ. Primary mediastinal B-cell lymphoma. Hematology Am Soc Hematol Educ Program. 2008;2008(1):349-358.
3. Dunleavy K, Pittaluga S, Maeda LS, et al. Dose-adjusted EPOCH-rituximab therapy in primary mediastinal B-cell lymphoma. N Engl J Med. 2013;368:1408-16.