[Standard CHOP immuno-chemotherapy for primary mediastinal lymphomas]

Primary mediastinal lymphoma (PMBCL) is an aggressive diffuse large B-cell lymphoma entity. It is a rare disease with specific clinical symptoms. The tumor is predominantly localized in the mediastinum but grows rapidly and infiltrates the surrounding tissues and organs. Two thirds of the patients are young females. Previous studies showed that third generation treatments are more effective than former standard cyclophosphamide-doxorubicin-vincristine-prednisolone (CHOP) regimens.

Authors' goal was to assess whether adding the anti-CD20 monoclonal antibody, rituximab to the standard CHOP regimen improves the efficacy of the treatment compared to their previous results with CHOP and third generation chemotherapy regimens.

Between October, 2002 and December, 2004 they have started the rituximab-CHOP (R-CHOP) treatment of 20 newly diagnosed, previously untreated PMBCL patients. Results were compared to the data of 24 patients receiving CHOP (n = 9) or procarbazin-prednisolone-doxorubicin-cyclophosphamide-etoposide-cytosin-arabinoside-bleomycin-vincristin-methotrexate (ProMACE-CytaBOM) (n = 15) treatment in the past.

During an average follow-up of 64.6 months, the 5-year overall survival (OS) rate was significantly higher in the R-CHOP group compared to the CHOP treatment (79.4% vs. 33.3%; p = 0.026). However, due to the low number of cases, significant statistical difference could not be demonstrated in the 5-year event-free survival (EFS: 70.0% vs. 33.3%; p>0.05), disease-free survival (DFS: 70.0% vs. 33.3%; p>0.05) and relapse-free survival rate (RFS: 93.0% vs. 100%; p> 0.05), despite of the remarkable numeric difference. When comparing the 5-year survival rates of R-CHOP and ProMACE-CytaBOM treatments, the results were very similar without any significant statistical difference between the two types of treatment (OS: 79.4% vs. 80%; EFS: 70.0% vs. 60.0%; DFS: 70.0% vs. 60.0%; RFS: 93.0% vs. 82.0%; p> 0.05 in all cases). With adding rituximab to CHOP treatment, which was previously considered an insufficient treatment on its own, authors have obtained as good results in treating PMBCL as with third generation regimens. Patients have received the R-CHOP treatments without major side effects and mainly as out-patients.

Standard R-CHOP treatment could therefore replace the more toxic third generation regimens in PMBCL as well. The data are comparable with those reported in the international literature.