Increased blood levels of beta-2 microglobulin in patients with diffuse large B-cell lymphoma (DLBCL) who were treated with the drug Rituxan (rituximab) can be a reliable predictor of poor prognosis, according to a new study.
The study, “Prognostic Significance Of Serum Beta-2 Microglobulin In Patients With Diffuse Large B-Cell Lymphoma In The Rituximab Era,” was published in the journal Oncotarget.
In recent years, treatment of DLBCL has improved with the addition of the anti-CD20 Rituxan to the existing therapy of Cytoxan (cyclophosphamide), Adryamycin (doxorubicin), Oncovin (vincristine), and Deltasone (prednisone) – also called CHOP therapy.
For the last two decades the International Prognostic Index (IPI) has been used to determine the prognosis of patients with DLBCL to predict clinical outcomes in the Rituxan-CHOP (R-CHOP) era.
But the standard IPI has suboptimal predictive power in high-risk patients with DLBCL, and although new prognostic tools such as the revised-IPI (R-IPI) and National Comprehensive Cancer Network (NCCN)-IPI improved identifying patients at risk, newer and better prognostic parameters are still required.
Previous studies showed that elevated blood beta-2 microglobulin is an independent prognostic factor in patients with DLBCL treated with CHOP or CHOP-like regimens, but no information was available about its reliability in patients treated with therapies that contain Rituxan.
For the recent study, researchers evaluated whether blood levels of beta-2 microglobulin can assist in the prognosis of patients with DLBCL treated with R-CHOP therapy. They analyzed records of 833 patients with DLBCL who were treated with R-CHOP therapy and established the prognostic value of blood beta-2 microglobulin levels at or above 2.5 mg/L.
Results indicated that patients with elevated blood beta-2 microglobulin had worse five-year progression-free survival (PFS) and overall survival (OS). Additionally, the five parameters of the IPI related with the disease symptoms, bone marrow involvement, and impaired kidney function were associated with worse PFS and OS.
The team then analyzed an additional group of 258 patients treated with the same therapy and confirmed that increased levels of beta-2 microglobulin levels also signaled poor prognosis.
“In summary, this study demonstrated that patients with DLBCL with elevated [blood] beta-2 microglobulin showed distinct adverse clinical features and followed a significantly worse clinical course,” the researchers wrote. “Further analysis confirmed the significance of beta-2 microglobulin as an independent prognostic factor for patients with DLBCL receiving R-CHOP immunochemotherapy.”