The lymphocyte-to-monocyte ratio could predict the efficacy of PD-1 inhibitors in patients with advanced cancer

BACKGROUND: PD-1/PD-L1 inhibitors have made remarkable achievements in the field of tumor treatment. However, most patients do not benefit from PD-1/PD-L1 inhibitor therapy, and some patients experience adverse reactions. Therefore, finding ideal prognostic indicators to predict the efficacy of PD-1/PD-L1 inhibitors and selecting populations that can potentially benefit clinically are crucial. The purpose of this retrospective analysis was to investigate the prognostic value of the lymphocyte-to-monocyte ratio (LMR) in patients with advanced tumors using PD-1 inhibitors to identify patients who may have a better response to PD-1 inhibitors. METHODS: The clinical data of 121 patients with advanced cancer at the Affiliated Tumor Hospital of Zhengzhou University were retrospectively analyzed. The receiver operating characteristic (ROC) curve was used to determine the best cutoff value of the LMR, and subsequently, the patients were divided into high- and low-LMR groups. Kaplan-Meier and log-rank tests were used to draw survival curves. Univariate and multivariate analyses used Cox proportional hazard regression models to assess the association between the LMR and overall survival (OS) or progression-free survival (PFS). RESULTS: The ROC curve showed that the areas under the curve at baseline and 6 weeks after anti-PD-1 antibody treatment LMR (LMR-week 1 and LMR-week 6, respectively) were 0.593 (P=0.164) and 0.713 (P=0.002), respectively. The optimal cutoff value of LMR-week 6 was 4.15, and in a total of 121 patients, 66 and 55 presented with LMR-week 6 <4.15 and ≥4.15, respectively. A low LMR-week 6 was associated with poor OS and PFS (P<0.001). The multivariate analysis showed that the independent factors related to OS were Eastern Cooperative Oncology Group (ECOG) performance status and LMR-week 6, and the independent factors related to PFS were smoking history, ECOG performance status, and LMR-week 6. The objective response rates (ORR) in the high- and low-LMR-week 6 groups were 32.7% and 7.6%, respectively, and were associated with elevated LMR-week 6 (P<0.001). CONCLUSIONS: LMR-week 6 is significantly related to the effect of anti-PD-1 antibody treatment; therefore, LMR-week 6 can be used as an early surrogate indicator for stratification in patients who respond better to anti-PD-1 drugs.