Prognostic value of tumor-infiltrating lymphocytes and their association with clinical and pathological factors in gastric cancer.

BACKGROUND: The prognostic value of tumor-infiltrating lymphocytes has been studied in several cancers, but in gastric cancer, their evaluation by standard hematoxylin-eosin staining remains controversial. AIMS: To analyze the prognostic value of tumor-infiltrating lymphocytes in gastric cancer and to investigate the association between tumor-infiltrating lymphocyte levels and a range of clinical and pathological factors in gastric cancer. RESULTS: Forty-four patients were included with a mean age of 62 years, and 77% of the patients were classified as having pathological tumor stage 3 or pathological tumor stage 4. Lymph node metastases were noted in 66% of our patients. At diagnosis, 57% of patients were at an advanced stage (III). Patients with distant metastases were not included in this study. Evaluation of tumor-infiltrating lymphocytes in hematoxylin-eosin staining found that the mean tumor-infiltrating lymphocyte rate was 43 (extremes: 5-90%). 36% of patients had a tumor-infiltrating lymphocyte rate >50%. The overall survival of our patients was 40 months. Patients with tumor-infiltrating lymphocytes >50% had greater survival, without a significant correlation (p=0.275). A tumor-infiltrating lymphocyte rate =50% was correlated with age >50 years (p=0.030), presence of lymph node involvement (p=0.023), and advanced tumor stage (III+IV) (p=0.05). In a multivariate analysis, the presence of lymph node involvement (p=0.045) and advanced tumor stage (III+IV) (p=0.015) were identified as independent factors associated with a low tumor-infiltrating lymphocyte rate =50%. CONCLUSIONS: Poor prognostic factors for gastric cancer (age >50 years, presence of lymph node involvement, and advanced tumor stage) were associated with a low tumor-infiltrating lymphocyte rate assessed by hematoxylin-eosin staining. However, standardization of tumor-infiltrating lymphocyte assessment is essential to allow comparability between studies and integrate this parameter into routine practice.