Background: Tumour-infiltrating CD8+ cell playing a pivotal role on cell-mediated immune response against cancer, has been tensely studied for several years on solid tumours implicating a better prognosis of patient survival. However, little is known about the prognostic significance of CD8+ cell of perihilar cholangiocarcinoma (CCA) which is the most common primary hepatic cancer in the Northeast of Thailand where also accounts for the highest CCA prevalence in the world .
Objective: To investigate the prognostic significance of tumour-infiltrating CD8+cell density on resectable perihilar cholangiocarcinoma.
Methods: We studied 150 cases of perihilar cholangiocarcinoma which were surgically resected between 2009 – 2015. Immunohistochemical staining for CD8 was performed on paraffin-embedded sections. The number of stained cells was numerated in two regions including intratumoural and peritumoural region. The relationship between density of CD8+ cell and overall survival were analyzed by using Kaplan-Meier analysis and log-rank test.
Results: Of 150 cases, 70% were male with a median age of 60 ± 10 years old (range: 50-75). The median overall survival after resection was 16 months. The cumulative 1-year, 3-year and 5-year survival was 75%, 48% and 32 % respectively. The median survival time of the CD8High groupwas 25 months (95%CI 17 – 31) and 14 months (95%CI 9 – 20) for CD8Low group.On multivariate analysis, it was found that intratumoural higher CD8+ density was associated with increased overall survival (HR 0.48, 95% CI 0.21-0.78, p-value 0.002).
Conclusions: The higher density of intratumoural CD8+ cells is a favorable marker predicting a better prognosis on resectable perihilar cholangiocarcinoma. It can be inferred that to increase number of CD8+ cell may be profitable strategy for novel immunotherapy applied for perihilar cholangiocarcinoma.
Key words: Perihilar cholangiocarcinoma, CD8, survival