Objective:

To evaluate the prognostic and predictive value of soluble interleukin-2 receptor (sCD25) in patients with stage IV lung adenocarcinoma (LUAD).

Approach:

• Study Design: A prospective observational study involving 133 patients with newly diagnosed stage IV LUAD, assessing overall survival (OS) in relation to baseline sCD25 levels.
• Statistical Analysis: Kaplan–Meier estimates, multivariable Cox regression, and propensity score matching were used to analyze associations between sCD25 and OS.

Key Findings:

• Elevated sCD25 (≥441 U/mL) was associated with shorter OS (HR, 5.70; 95% CI, 2.94–11.07; P <.0001).
• One- and three-year OS rates were significantly lower in high sCD25 patients compared to low sCD25 patients (97% and 78% for low sCD25 vs. 68% and 27% for high sCD25).
• A significant treatment interaction was observed for EGFR-TKIs, with benefits limited to the high-sCD25 subgroup (HR, 0.41; 95% CI, 0.19–0.88; P =.02).

Interpretation:

Baseline sCD25 is a strong prognostic biomarker in stage IV LUAD.

Limitations:

• The study was conducted at a single center, which may limit generalizability.
• Further multicenter validation is warranted.

Conclusion:

Baseline sCD25 may have implications for treatment response in stage IV LUAD patients.