Features of the intestinal microbiota in a patient with colorectal cancer

The incidence of inflammatory bowel diseases, particularly the immune-mediated progressive condition known as ulcerative colitis, is currently on the rise. Significant risk factors for the development of colorectal cancer include a positive family history as well as the characteristics of the intestinal microbiota, which may influence carcinogenesis by impacting the genomic stability of host cells. Objective. To evaluate the generic biodiversity of the intestinal microbiota in a patient diagnosed with ulcerative colitis who subsequently developed sigmoid colon cancer. Materials and methods. This paper presents a clinical case of a patient with ulcerative colitis complicated by cancer. Results. A patient presented to a gastroenterologist with gastrointestinal symptoms and signs, including bloody diarrhea, tenesmus, persistent pain localized to the left iliac and lateral regions, spastic pain in the aforementioned location prior to defecation, as well as general weakness, dizziness, and fatigue. In November 2024, the patient was diagnosed with left-sided ulcerative colitis, chronic relapsing course, mild attack. The family history included colorectal cancer in the patient’s mother and both ulcerative colitis and colorectal cancer in the patient’s sister. Following therapy, the patient achieved clinical remission. In January 2024, the patient underwent 16S rRNA sequencing of stool samples, which indicated increased abundance of some bacterial genera, including Fusobacterium, Bacteroides, Faecalibacterium, Streptococcus, and Butyricimonas, all of which are associated with oncogenesis. Intermittent bloody diarrhea persisted throughout 2024, alongside the emergence of aforementioned symptoms. Following an examination by specialists, the diagnosis has now been established: «Ulcerative colitis, chronic relapsing course, pancolitis, remission. Sigmoid colon cancer with multiple metastases, T4N3M1». Conclusions. This clinical case underscores the significant roles of family history and gut microbiota composition in cancer development in patients with ulcerative colitis.