A Narrative Review Study Summarizing and Interpreting the Existing Literature on the Diagnosis and Treatment of Small Bowel Tumors

Abstract Small intestine cancer encompasses a group of malignant diseases originating in the duodenum, jejunum, or ileum. Although they account for only 3-5% of all gas-trointestinal carcinomas, their incidence is increasing, unlike more common malignant diseases, such as colorectal carcinoma, which makes their study increasingly important. Objective to analyze the main malignant histological subtypes – adenocarcinomas, neuroendocrine neoplasms, gastrointestinal stromal tumors, and lymphomas – and to summarize and systematize the available literature data. Materials and Methods We applied a narrative review study design involving the summarization and interpretation of existing literature data on the given topic and objective in order to create a structured, comprehensive scientific product on malignant diseases of the small intestine. We analyzed 20 literature sources. Results and Discussion The etiology of small intestine cancer is multifactorial and can be divided into well-defined hereditary cancer syndromes and acquired chronic inflammatory conditions. Malignant tumors of the small intestine are a rare but increasingly common group of diseases that are difficult to manage due to their heterogeneity. This biological heterogeneity requires highly specific diagnostic, surgical, and systemic (e.g., targeted therapy for GIST, immunotherapy for MSI-H SBA, PRRT with 177Lu-DOTATATE for NETs) management strategies. Optimal results for the treatment of these rare tumors require a specialized, multidisciplinary approach, concentrated in high-tech centers and institutions.