Circulating Lymphocytes as Predictors of Sensitivity to Preoperative Chemoradiotherapy in Rectal Cancer Cases

Objective: The objective of this study was to identify clinical predictive factors for tumor response afterneoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC).
Methods: All factors wereevaluated in 88 patients with LARC treated with nCRT. After a long period of 4-8 weeks of chemoradiotherapy,3 patients achieved clinical complete response (cCR) and thus aggressive surgery was avoided, and the remaining85 patients underwent a curative-intent operation. The response to nCRT was evaluated by tumor regressiongrade (TRG) system.
Results: There were 32 patients (36.4%) with good tumor regression (TRG 3-4) and 56(63.6%) with poor tumor regression (TRG 0-2). Lymphocyte counts and ratios were higher in good responsecases (P=0.01, 0.03, respectively) while neutrophil ratios and N/L ratios were higher in poor response cases(P=0.04, 0.02, respectively). High lymphocyte ratios before nCRT and good tumor regression (TRG3-4) weresignificantly associated with improved 5-year disease-free survival (P<0.05). Pretreatment nodal status wasalso significantly associated with 5-year disease-free survival and 5-year overall survival (P<0.05). Multivariateanalysis confirmed that the pretreatment lymphocyte ratio and lymph nodal status were independent prognosticfactors.
Conclusion: Our study suggested that LARC patients with high lymphocyte ratios before nCRT wouldhave good tumor response and high 5-year DFS and OS.