Impact of lymphocyte infiltration on the survival of patients with gastric and colorectal cancers at the Yaoundé General Hospital (Cameroon).

Introduction: digestive cancers (DC) are a group of cancers affecting the gastrointestinal tract and are capable of triggering an immune response. The cells produced during this response are tumor effectors whose role is to rid the body of tumor cells. The functional role of these cells, particularly the tumor-infiltrating lymphocytes (TILs), in the prognosis of patients remains poorly understood in Cameroon. This study aimed to evaluate the impact of lymphocyte infiltration on the survival of patients with certain digestive cancers. Methods: we conducted a retrospective cross-sectional study at the Oncology Department and the Anatomo-Cytopathology Laboratory of the Yaoundé General Hospital (YGH). Patients histologically diagnosed with colorectal and gastric cancers with available data from YGH between 2019 and 2023, who consented to participate and had a biopsy sample available at the YGH laboratory, were included in the study. Initially, we described patients' sociodemographic, clinical, and pathological characteristics. Then, we estimated the grade of lymphocyte infiltration in colorectal and gastric cancers using Hematoxylin-Eosin (HE) staining and analyzed the correlation between lymphocyte infiltration and patient survival through Cox regression. Data were analyzed with a significance level set at 5% for all comparisons. Results: the study enrolled 90 patients with colorectal cancer and 50 with gastric cancer. Overall survival was 64.8% at 49 months in the study population, with the median not reached for colorectal cancer, and 64% at 39 months for gastric cancer, also with a median not reached. The average age at diagnosis for colorectal and gastric cancers was 54 ± 14.53 years and 53.24 ± 11.41 years, respectively. Men predominated in both pathologies, with a sex ratio of approximately 1.11. Colonic location was predominant (53%; 46/90) for colorectal cancer, with stage III disease being most common, while the antropyloric location (46%; 23/50) was predominant for gastric cancer, with stage IV being most frequent according to the AJCC. Moreover, 86% of patients had TILs in their histological samples, with a predominance of high TILs in both colorectal (38%; 34/90) and gastric (42%; 21/50) cancers. The performance of chemotherapy was inversely proportional to TILs in colorectal cancer, while no significant difference was found between TILs and chemotherapy in gastric cancer. However, no association was found between TILs and patient survival in either colorectal or gastric cancers. Patients who had metastases had a risk of death of 14.07 (aHR: 14.07, 95% CI 1.66-119.24; p = 0.015) compared with those who did not. Similarly, patients who had not taken chemotherapy had a 21.32 greater risk of death (aHR: 21.32, 95% CI 5.35-84.96; p<0.001) than those who had. Conclusion: there was no statistically significant difference in survival between patients suffering from colorectal and gastric cancers, and the grade of lymphocyte infiltration. Survival was significantly impacted by the presence of metastasis and the absence of treatment.