5489 - Local immune status in cancer cell nests can be a predictor of survival for rectal cancer with neoadjuvant radiotherapy

Background

Although neoadjuvant chemoradiotherapy is the standard treatment for locally advanced rectal cancer (LARC), it remains difficult to predict the prognosis of LARC patients. We aimed to explore the impacts of local immune status on survival of LARC after noeadjuvant radiotherapy (nRT).

Methods

A total of 76 consecutive LARC patients were enrolled in our institute from February 2012 to September 2015. CD3+ T-cell and CD8+ T-cell count were determined from surgical specimens. Factors associated with disease-free survival (DFS) and overall survival (OS) were identified by univariate and multivariate Cox regression. SPSS 22.0 was used for statistical analyse.

Results

The median follow-up time was 29.0 months (range 2.0-59). The Cutoff Finder software identified an optimal CD3+ T-cell cutoff value of 12.5% and CD8+ T-cell value of 9% for our patients. According to the Kaplan-Meier analysis, CD3+ T-cell ≥12.5% was significantly related to favorable DFS (P = 0.020), while there was no significant difference between CD3+ T-cell and OS (P = 0.238). Meanwhile, CD8+ T-cell ≥9% was found to have a positive effect on DFS and OS (P = 0.012 and P = 0.035, respectively). In the multivariate Cox regression model, CD8+ T-cell <9% was independent risk factors for poor DFS (HR = 0.492, 95%CI= 0.252-0.960, P = 0.038). Furthermore, CD8+ T-cell (HR = 0.268, 95%CI= 0.076-0.941, P = 0.040) and T stage (HR = 0.151, 95%CI= 0.030-0.7530, P = 0.021) were independent predictors of OS.

Conclusions

High CD8+ T-cell count were significantly related to good survival in LARC patients with nRT. Local immune status was suggested to be measured in order to predict the prognosis of patients with LACR after nRT.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Xijin Lin.

Funding

The Fujian Province Natural Science Foundation (2017J01260), Joint Funds for the Innovation of Science and Technology, Fujian province (2017Y9074), and the Peking University Cancer Hospital & Institute, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education/Beijing (2017 Open Project-9).

Disclosure

All authors have declared no conflicts of interest.