Peripheral Blood Lymphocyte Subsets and Long-Term Clinical Outcomes in Prostate Cancer Patients: An Eight- Year Follow-up Study

Abstract

Background: The clinical outcomes of prostate cancer (PC) may be influenced by changes in immune profiles. However, the precise correlation between the long-term prognosis of PC and circulating lymphocytes remains uncertain. Therefore, our study aimed to characterize circulating lymphocyte subsets and investigate their relationship with the long-term clinical outcomes in PC patients. Materials: The prospective cohort study included patients with a pathological diagnosis of PC and Gleason Grades ranging from 5 to 10. Lymphocyte counts were assessed in peripheral blood using flow cytometry. The prognostic value of various lymphocytes was analyzed in the entire cohort, with survival curves generated using the Kaplan-Meier method and multivariate analysis performed using Cox regression models. Results: Between January 2001 and June 2021, a total of 94 eligible patients with prostate cancer were prospectively enrolled. The median follow-up duration for the study was 98 months. Non-survivors exhibited lower levels of CD4(+)/CD8(+) ratio, CD19(+), and CD19(+)CD5(−) B lymphocytes compared to survivors. Grouping by each cutoff point of the lymphocytes respectively, the lower level of total CD3(+) T cells, CD3(+)CD4(+) T cells, the CD4(+)/CD8(+) ratio, total CD19(+) B cells, CD19(+)CD5(+) B cells, CD19(+)CD5(-) B cells showed poor survival. Multivariate Cox regression analysis confirmed the worse prognosis associated with higher PSA (HR=2.493, 95%CI: 1.356-4.584, P=0.003), lower CD3(+)CD4(+) T lymphocytes (HR=0.379, 95%CI: 0.170-0.843, P=0.017), lower total CD19(+) B cell (HR=0.398, 95%CI:0.187-0.845, P=0.016) and higher CD3(-)CD16(+)CD56(+) NK cells(HR=2.355, 95%CI: 1.175-4.723, P=0.016). Conclusion: Our findings revealed that a reduced level of CD4(+) T lymphocytes, diminished CD19(+) B cells, and an elevated level of NK cells were associated with poor survival. This suggests potential involvement of B lymphocytes, CD4(+) T lymphocytes, and NK cells in prostate cancer, with implications for the long-term prognosis of these elderly patients.