High systemic immune-inflammation index predicts poor prognosis in advanced lung adenocarcinoma patients treated with EGFR-TKIs

EGFR-TKIs have been widely used in the first-line treatment of NSCLC patients harboring EGFR mutations. However, the prognosis indicators are limited. In the present study, the prognostic value of systemic immune-inflammation index (SII), neutrophil to lymphocyte ratio (NLR), and platelet to lymphocyte ratio (PLR) were assessed in EGFR-Mutant lung adenocarcinoma patients treated with first-generation EGFR-TKIs. Two hundred three patients were included in this retrospective analysis. SII was calculated as platelet counts x neutrophil counts / lymphocyte counts. Receiver operating characteristic (ROC) curve was used to evaluate the optimal cut-off value for SII, NLR, and PLR. Univariate and multivariate survival analysis were performed to identify factors correlated with PFS and OS. Applying cut-offs of >= 1066.935 (SII), >= 4.40 (NLR), and >= 182.595 (PLR), higher NLR was associated with worse Eastern Cooperative Oncology Group performance status (ECOG PS) (P=.006), and higher brain metastasis rate (P=.03), higher PLR was associated with smoking history (P=.037), and worse ECOG PS (P=.001), and higher SII groups were associated with worse ECOG PS (P=.002). In univariate analysis, higher NLR (P<.001), higher PLR (P=.002), and higher SII (P<.001) were associated with worse PFS. Higher NLR (P<.001), and higher SII (P<.001) were associated with worse OS. In multivariate analysis, NLR (HR 1.736; 95% CI: 1.020-2.954; P=.03), PLR (HR 1.823; 95% CI: 1.059-3.137; P=.04), and SII (HR2.577; 95% CI: 1.677-3.958; P<.001) were independently correlated with PFS. While only SII (HR 2.802; 95% CI: 1.659-4.733; P<.001) was independently correlated with OS. The present study demonstrated that SII is an independent prognostic factor for poor survival of advanced EGFR-Mutant lung adenocarcinoma patients treated with first-generation TKIs.