Soluble interleukin-2 receptor retains prognostic value in patients with diffuse large B-cell lymphoma receiving rituximab plus CHOP (RCHOP) therapy

Background: Soluble interleukin-2 receptor (SIL-2R) is knownto be a prognostic parameter in patients with diffuse largeB-cell lymphoma (DLBCL) receiving cyclophosphamide, doxorubicin,vincristine and prednisone (CHOP) therapy. However, its prognosticvalue has not been well known since the introduction of rituximab. Patients and methods: We retrospectively evaluated the prognosticimpact of SIL-2R in 228 DLBCL patients, comparing 141 rituximab-combinedCHOP (RCHOP)-treated patients with 87 CHOP-treated patientsas a historical control. Results: Patients with high serum SIL-2R showed significantlypoorer event-free survival (EFS) and overall survival (OS) thanpatients with low SIL-2R in both the RCHOP group (2-year EFS,66% versus 92%, P < 0.001; OS, 82% versus 95%, P = 0.005)and the CHOP group (2-year EFS, 40% versus 82%; OS, 61% versus90%, both P < 0.001). Multivariate analysis including thefive parameters of International Prognostic Index (IPI) andtwo-categorized IPI revealed that SIL-2R was an independentprognostic factor for EFS and OS in the RCHOP group as wellas in the CHOP group. Conclusions: Our results demonstrate that SIL-2R retains itsprognostic value in the rituximab era. The prognostic valueof SIL-2R in DLBCL patients receiving rituximab-combined chemotherapyshould be reassessed on a larger scale and by long-term follow-up. Key words: diffuse large B-cell lymphoma, rituximab, soluble interleukin-2 receptorReceived for publication July 5, 2008. Revision received September 11, 2008. Accepted for publication September 16, 2008.