Radio-induced apoptosis of peripheral blood CD8 T lymphocytes is a novel prognostic factor for survival in cervical carcinoma patients

Background and purpose. A close relationship exists between immune response and tumor behavior. This study aimed to explore the associations between radiation-induced apoptosis (RIA) in peripheral blood lymphocytes (PBL) and clinical pathological variables. Furthermore, it assessed the role of RIA as a prognostic factor for survival in cervical carcinoma patients. Patients and methods. Between February 1998 and October 2003, 58 consecutive patients with nonmetastatic, localized stage I-II cervical carcinoma who had been treated with radiotherapy (RT) +/- A chemotherapy were included in this study. Follow-up ended in January 2013. PBL subpopulations were isolated and irradiated with 0, 1, 2 and 8 Gy then incubated for 24, 48 and 72 h. Apoptosis was measured by flow cytometry and the beta value, a parameter defining RIA of lymphocytes, was calculated. Results. Mean follow-up duration was 111.92 +/- 40.31 months. Patients with lower CD8 T lymphocyte beta values were at a higher risk of local relapse: Exp(B) = 5.137, confidence interval (CI) 95 % = 1.044-25.268, p = 0.044. Similar results were observed for regional relapse: Exp(B) = 8.008, CI 95 % = 1.702-37.679, p = 0.008 and disease relapse: Exp(B) = 6.766, CI 95 % = 1.889-24.238, p = 0.003. In multivariate analysis, only the CD8 T lymphocyte beta values were found to be of prognostic significance for local disease-free survival (LDFS, p = 0.049), regional disease-free survival (RDFS, p = 0.002), metastasis-free survival (MFS, p = 0.042), disease-free survival (DFS, p = 0.001) and cause-specific survival (CSS p = 0.028). Conclusion. For the first time, RIA in CD8 T lymphocytes was demonstrated to be a predictive factor for survival in cervical carcinoma patients.