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Título

PROGNOSTIC IMPLICATIONS OF TUMOR-INFILTRATING LYMPHOCYTES IN ASSOCIATION WITH PD-L1 EXPRESSION IN REMNANT GASTRIC CANCER

Resumo

BACKGROUND:
Remnant gastric cancer (RGC) can occur either after a previous resection for benign or malignant lesions, and it is usually associated with a worse prognosis. As they are less common and very heterogeneous tumors, new prognostic determinants are required to predict patients’ clinical course for RGC.
AIM:
This study aimed to investigate the tumor-infiltrating lymphocytes (TILs) and Programmed death ligand-1 (PD-L1) status as prognostic biomarkers in a cohort of patients with RGC to develop an immune-related score.
METHODS:
Patients with GC who underwent curative intent gastrectomy at our Institute between 2009 and 2019 were retrospectively investigated. RGC resections with histological diagnosis of gastric adenocarcinoma were enrolled in the study. Clinical and pathological data were collected from a prospective medical database. The risk score based on immune parameters was developed using binary logistic regression analysis, and calculated for each patient. Subsequently, RGCs were divided into high-risk (HR), intermediate risk (IR), and low-risk (LR) groups based on their immune score.
The markers (CD3+, CD4+/CD8+ T cells and PD-L1) were selected for their potential prognostic, therapeutic value, and evaluated by immunohistochemistry (IHC).
RESULTS:
A total of 42 patients with RGC were enrolled in the study. The mean staining for TILs CD3+ and CD4+/CD8+ ratio assessed by IHC was: 40% (SD 17.3, median 45.9) and 1.1 (SD 0.8, median 0.9), respectively. Positivity for PD-L1 was observed in 13 (30.9%) cases. The score based on immune parameters exhibited an accuracy of 79% (AUC 0.79, 95%CI 0.63 – 0.94, p=0.002), and the population was divided into 3 prognostic groups: 10 (23.8%) patients were classified LR, 15 (35.7%) as IR, and 17 (40.5%) as HR groups. There were no differences in clinicopathological and surgical characteristics between the 3 groups. In survival analysis, HR and IR groups had worse disease-free survival and overall survival rates compared to the LR patients. In the multivariate analysis, lymph node metastasis and the immune score risk groups were independent factors related to worse survival.
CONCLUSION:
A scoring system with immune-related markers was able to distinguish prognostic groups of RGC independently associated with survival. Accordingly, tumor-infiltrating immune lymphocytes and PD-L1 status may serve as a potential prognostic biomarker for patients with RGC