Epidemiological and molecular evaluation of BRAF, KRAS, NRAS genes and MSI in the development of colorectal cancer.

BACKGROUND AND OBJECTIVES: KRAS, NRAS, BRAF mutations and microsatellite instability (MSI) can be associated with Colorectal Cancer (CRC) development. MATERIAL AND METHODS: We evaluated 828 medical records of CRC patients from a school hospital from January/2016 to December/2020. Variables such as age, gender, ethnicity, literacy level, smoking, alcoholism, primary anatomical site, tumor staging, presence of BRAFV600E, KRAS, NRAS mutations and MSI , survival and metastasis were identified. The statistical analyses were performed (p < 0.05 was considered significant). RESULTS: There was a predominance of males (51.93%), whites (90.70%), low education (72.34%), smokers (73.79%), and non-alcoholics (79.10%). Rectum was the most affected site (42.14%), advanced tumor stage was most prevalent (62.07%), and metastasis occurred in (64.61%). Of the enrolled patients; 204 were investigated for BRAF mutation and detected in (2.94%); 216 for KRAS gene and detected in (26.08%); 210 for NRAS gene, and detected in (25.36%); 370 for MSI and detected in (44.68%). A significant association of CRC with NRAS mutation and alcohol habit (p = 0.043) was observed. The presence of MSI was associated with primary site proximal colon (p < 0.000), distal colon (p = 0.001) and rectum (p = 0.010). CONCLUSION: Patients with CRC are male, over 64 years old, white, with low education, smokers and non-alcoholics. The most affected primary site is rectum in advanced stage with metastasis. CRC is associated with NRAS mutation and alcohol habit, there is increased risk for primary site of proximal colon and MSI; decreased risk for distal colon and rectum in the presence of MSI.

[Endoscopic aspects in the diagnosis of terminal ileum diseases]. / Aspectos endoscópicos no diagnóstico de doenças que acometem o íleo terminal.

The ileum is approximately the most distal three-fifths of the small intestine and is responsible for the digestion and the absorption of foods. The diagnosis of diseases that affects this segment can be achieved by clinical evaluation and complementary examinations. Not only does ileocolonoscopy allow macroscopical analysis, but also enables biopsies to be carried out for histological evaluation. Only three publications about the description of the endoscopic characteristics of the terminal ileum have been found in the literature. Even so, there have not been found descriptions or classifications in publications that mentioned endoscopic aspect of the terminal ileum, being reported only as normal ileum. Therefore, this strengthens the idea of the lack of knowledge or the non-acceptance of these descriptions and these classifications by the scientific community. Endoscopic aspects of this segment when affected by several diseases vary from normal endoscopically ileum to cases when the macroscopical examination demonstrate specific features of these illnesses. In the present investigation, there are doubts about the need of biopsy of this segment in patients with normal ileoscopy. Moreover, few studies with criteria for macroscopical and microscopical characterization of the ileum were found.

Terminal ileum of patients who underwent colonoscopy: endoscopic, histologic and clinical aspects / Íleo terminal de pacientes submetidos a colonoscopia: aspectos endoscópicos, histológicos e clínicos

CONTEXT: For the diagnosis of the diseases which affect the terminal ileum, the colonoscopy allows macroscopic evaluation and the performing of biopsies. Studies with criteria for the endoscopic and histological characterization of this segment are scarce and there are still some doubts about the need of biopsies in patients with normal ileoscopy. OBJECTIVE: Study the terminal ileum of patients who underwent colonoscopy considering: endoscopic and histological correlation; agreement between results of the initial histological evaluation and slides review, and the chance of subjects with normal ileoscopy with abdominal pain and/or chronic diarrhea to show histological alterations. METHODS: In a prospective study, 111 patients who presented smooth mucosa without enanthema in the endoscopic exam of the terminal ileum were selected. Biopsies of the ileal mucosa of such patients were performed, being the slides routinely examined and reviewed afterwards. RESULTS: The correlation between patients with normal ileoscopy and ileum with preserved histological architecture was of 99.1 percent. The agreement between initial histological evaluation and slides review calculated by the Kappa test was 0.21. In patients with abdominal pain and/or chronic diarrhea, the chance of showing histological alterations was 2.5 times higher than the others. CONCLUSIONS: The correlation between endoscopic and histological findings was high. The agreement between the initial histologic evaluation and slides review was not satisfactory. The chance of subjects with normal ileoscopy with abdominal pain and/or chronic diarrhea, showing histological alterations was higher in relation to the asymptomatic ones or with other symptoms, although the clinical importance of this datum was not evaluated.

CONTEXTO: Para o diagnóstico de doenças que afetam o íleo terminal, a colonoscopia permite avaliação macroscópica e realização de biopsias. Estudos com critérios para caracterização endoscópica e histológica desse segmento são escassos e ainda persistem dúvidas quanto à necessidade de biopsias em pacientes com ileoscopia normal. OBJETIVO: Estudar o íleo terminal de pacientes submetidos a colonoscopia, considerando correlação endoscópica e histológica; concordância entre resultados da avaliação histológica inicial e revisão de lâminas e chance de indivíduos com ileoscopia normal, com dor abdominal e ou diarreia crônica apresentarem alterações histológicas. MÉTODOS: Estudo prospectivo, no qual foram selecionados 111 pacientes, que apresentaram ao exame endoscópico do íleo terminal mucosa lisa e sem enantema. Foram realizadas biopsias da mucosa ileal nesses indivíduos, sendo as lâminas examinadas rotineiramente e revisadas posteriormente. RESULTADOS: A correlação entre pacientes com ileoscopia normal e íleo com arquitetura histológica preservada foi de 99,1 por cento. A concordância entre avaliação histológica inicial e revisão de lâminas calculada pelo teste de Kappa, foi 0,21. Nos pacientes com ileoscopia normal, com dor abdominal e ou diarreia crônica, a chance de apresentarem alterações histológicas foi 2,5 vezes maior em relação aos demais. CONCLUSÃO: A correlação entre achados endoscópicos e histológicos foi elevada. A concordância entre avaliação histológica inicial e revisão de lâminas não foi satisfatória. A chance de indivíduos com ileoscopia normal, com dor abdominal e ou diarreia crônica, apresentarem alterações histológicas foi maior, porém a importância clínica desse dado não foi avaliada.