Prognostic value of post-treatment serum soluble interleukin-2 receptor in newly diagnosed diffuse large B-cell lymphoma patients who achieved complete metabolic response following R-CHOP therapy

Patients with DLBCL achieving complete metabolic response (CMR) after initial treatment with R-CHOP generally have a favourable prognosis; however, there are no established prognostic biomarkers for relapse in these patients. Soluble interleukin-2 receptor (sIL-2R) levels at diagnosis are prognostic factors in patients with DLBCL. However, the significance of post-treatment sIL-2R levels is unclear. To determine the significance of post-treatment serum sIL-2R levels on subsequent relapse and survival, we retrospectively analysed 485 patients with newly diagnosed DLBCL who received R-CHOP treatment and achieved CMR. The cumulative incidence of relapse (CIR) was significantly higher in patients with elevated post-treatment sIL-2R levels than in those with normal sIL-2R levels (five-year CIR; 38.8% vs. 12.8%). The prognostic value remained significant in multivariable analysis (hazard ratio, 2.30; p < 0.001). Five-year progression-free survival (49.0% vs. 83.5%) and overall survival (61.7% vs. 91.6%) rates were lower in patients with elevated post-treatment sIL-2R levels than in those with normal sIL-2R levels (p < 0.001 for both). In patients with newly diagnosed DLBCL who achieved CMR after R-CHOP treatment, the post-treatment serum sIL-2R level was an independent prognostic marker of subsequent relapse and survival.