CD8-positive Tumor-infiltrating Lymphocytes and Prognosis in Radiotherapy for Uterine Cervical Squamous Cell Carcinoma

Abstract

Background/aim: Prognostic factors, including CD8-positive tumor-infiltrating lymphocytes (CD8⁺TILs), in definitive radiotherapy (RT) for squamous cell carcinoma (SqCC) of the uterine cervix need to be studied. This study aimed to explore these factors in a retrospective cohort.

Patients and methods: Patients with SqCC who underwent definitive RT comprising external beam RT and intracavitary brachytherapy at our facility between April 2006 and November 2013 were evaluated. CD8 immunohistochemistry was performed in pre-treatment biopsy samples to analyze the prognostic significance of CD8⁺TILs in the tumor nest. Positive staining was defined as at least one CD8⁺ lymphocyte infiltrating the tumor area in the specimen.

Results: In total, 150 consecutive patients were included. Among them, 66 (43.7%) patients had International Federation of Gynecology and Obstetrics (FIGO, 2008 edition) stage IIIA or higher progressive disease. The median follow-up period was 61 months. In the entire cohort, the 5-year cumulative rates of overall survival (OS), progression-free survival (PFS), and pelvic recurrence-free rate (PRFR) were 75.6%, 69.6%, and 84.8%, respectively. Of the 150 patients, 120 (80.0%) patients were CD8⁺TIL positive. The independent favorable prognostic factors were FIGO stage I or II disease, administration of concurrent chemotherapy, and CD8⁺TILs for OS (p=0.028, 0.005, and 0.038, respectively); FIGO stage I or II disease and CD8⁺TILs for PFS (p=0.015 and <0.001, respectively); and CD8⁺TILs for PRFR (p=0.017).

Conclusion: The presence of CD8⁺TILs in the tumor nest may be a favorable prognostic factor of survival after definitive RT in patients with SqCC of the uterine cervix.

Keywords: CD8; Cervical cancer; radiotherapy; squamous cell carcinoma; tumor-infiltrating lymphocytes.