Abstract
Background: The effect of adjuvant chemotherapy in stage II colorectal cancer (CRC) patients has been in controversy for a long time. Our study aimed to find an effective inflammatory marker to predict the effect of chemotherapy.Methods: 708 stage II CRC patients in our institution were included. The subpopulation treatment effect pattern plot (STEPP) analysis was used to determine the optimal inflammatory marker and cut-off value. Propensity score matching (PSM) was performed to balance discrepancy between the chemotherapy and non-chemotherapy group. Survival analysis based on overall survival (OS) and cancer-specific survival (CSS) was performed using Kaplan-Meier methods with log-rank test and Cox proportional hazards regression. The restricted mean survival time (RMST) was used to measure treatment effect.Results: Platelet to Lymphocyte Ratio (PLR) was chosen as the optimal marker with a cut-off value of 130 according to STEPP analysis. In overall survival analysis, PLR level was significantly associated with the effect of chemotherapy (interaction p=0.027). In low-PLR subgroup, chemotherapy patients did not have a better OS than non-chemotherapy patients (RMST: 56.0 months vs. 56.0 months, HR: 0.983, 95 % CI: 0.528-1.829). In high-PLR subgroup, chemotherapy patients had a significant better OS than non-chemotherapy patients (RMST: 56.5 months vs. 51.3 months, HR: 0.371, 95% CI: 0.212-0.649). After PSM, PLR level was still associated with the effect of chemotherapy. In cancer-specific survival analysis, PLR level was not significantly associated with the effect of chemotherapy (interaction p=0.116). In low-PLR subgroup, chemotherapy patients did not have a better CSS than non-chemotherapy patients (RMST: 56.0 months vs. 56.0 months, HR: 1.016, 95 % CI: 0.494-2.087). In high-PLR subgroup, chemotherapy patients had a better CSS than non-chemotherapy patients (RMST: 56.5 months vs.51.3 months, HR: 0.371, 95% CI: 0.212-0.649). After PSM, PLR level was not associated with the effect of chemotherapy.Conclusions: PLR is an effective marker to predict the effect of chemotherapy in stage II CRC patients.
The platelet to lymphocyte ratio is a potential inflammatory marker predicting the effects of adjuvant chemotherapy in patients with stage II colorectal cancer