Prognostic value of the soluble interleukin-2 receptor level after patients with follicular lymphoma achieve a response to R-CHOP

Objectives: Follicular lymphoma (FL) is a clinically and biologically heterogeneous disease. Therefore, it is important to identify factors that can predict its clinical outcome. Methods: We retrospectively evaluated the usefulness of soluble interleukin-2 receptor (sIL-2R) levels after R-CHOP (posttreatment sIL-2R) in 72 patients with newly diagnosed FL who had either a complete response (CR) or partial response. With the use of a recursive partitioning analysis, we determined the cut-off values of post- and pretreatment sIL-2R levels that were associated with disease progression, which corresponded to 486.5 and 5405U/mL, respectively. Results: The high posttreatment sIL-2R group showed a significantly inferior progression-free survival (PFS) compared to the low posttreatment sIL-2R group in all patients (3-year PFS 52.6% vs. 77.4%, P=0.003), and in patients with CR (3-year PFS 57.1% vs. 82.1%, P=0.034). Although a multivariate analysis showed that pretreatment sIL-2R, but not posttreatment sIL-2R, was an independently significant predictive factor for disease progression, among patients with low pretreatment sIL-2R levels, those with high posttreatment sIL-2R levels tended to have inferior PFS. There was a significant trend in PFS among the high pretreatment sIL-2R group, the low pre- and high posttreatment sIL-2R group, and the low pre- and low posttreatment sIL-2R group (P<0.001). Conclusion: Among patients with a low pretreatment sIL-2R level who exhibited a positive response to R-CHOP, the posttreatment sIL-2R level may help to identify those with a poor prognosis.