Analysis of the Correlation Between Peripheral Blood Lymphocyte Subsets and Pathological Complete Response Rate in Rectal Cancer Patients Treated With Neoadjuvant Chemoradiotherapy
Chen Chen, Jinru Lin, Zhiyuan Zheng, Xiaoxue Huang, Jianyuan SongIntroduction
Locally advanced rectal cancer receives neoadjuvant chemoradiotherapy (nCRT) as standard clinical management. Reliable non-invasive biomarkers for predicting pathological complete response (pCR) after nCRT remain urgently needed. This study aimed to explore correlations between peripheral blood lymphocyte subsets and pCR rate in rectal cancer patients receiving nCRT, and screen predictive immune markers for individualized therapeutic decision-making.
Methods
This was a retrospective cohort study. A total of 143 rectal cancer patients receiving nCRT in our center between June 2021 and December 2022 were consecutively enrolled. Tumor regression grade (TRG) was applied to evaluate pathological treatment response. Kolmogorov–Smirnov test, Mann–Whitney U test, chi-squared test, binary logistic regression and ROC curve analyses were performed to investigate associations between lymphocyte subsets and pCR.
Results
A total of 48 patients (33.6%) achieved pCR after nCRT. Absolute counts of all detected peripheral blood lymphocytes after nCRT. Gender and age were correlated with lymphocyte subsets: males had higher absolute counts and percentages of NK cells than females (P<0.05); patients younger than 65 years had higher percentages of CD3+T cells and CD3+CD4+T cells, and lower NK cells (P<0.05). Multivariate logistic regression demonstrated that age <65 years (P=0.038), TNM stage I (P=0.026), longer interval between radiotherapy and surgery (P=0.003), and higher percentage of CD3+T cells (P=0.043) were independent predictive factors for pCR. ROC analysis revealed that CD3+T-cell percentage yielded an AUC of 0.673 (95% CI:0.581-0.764) for pCR prediction, with optimal cutoff value 68.155, sensitivity 0.563 and specificity 0.726.
Conclusion
The percentage of peripheral blood CD3+ T cells may serve as a non-invasive predictive marker for the efficacy of neoadjuvant chemoradiotherapy (nCRT) in rectal cancer (RC) patients. Combined with age, tumor stage, and treatment interval, it may help optimize individualized treatment regimens.