MODERN ASPECTS OF DIAGNOSTICS RECTAL CANCER (literature review)

Modern diagnosis of rectal cancer (RC) includes standard and special examination methods and tests. A physical examination of patients with suspected RC with anamnesis and examination, including a finger rectal examination, is still informative. The diagnostic specificity of the CEA and CA 19-9 cancer markers in the diagnosis of RC is limited; the definition of the SCC cancer marker, due to its specificity, is quite informative in the diagnosis of squamous cell RC. The main method of diagnosis of RC is endoscopic examination – colonoscopy or rectoscopy with biopsy. In detecting early RC, the sensitivity and specificity of the endoscopic method increases with the use of methods such as magnifying endoscopy, narrow-spectrum endoscopy, chromoendoscopy, and fluorescence diagnostics. To assess the prevalence of the tumor process, MRI, CT with intravenous contrast, in particular CT colonography, are used. There has been progress in research using artificial intelligence based on MRI in assessing the stage, predicting high-risk factors, genotyping, response to therapy, recurrence, metastasis, and prognosis in RC. Transabdominal ultrasound of the abdominal organs, transrectal and endorectal ultrasound, supplemented with elastography, if necessary, provides sufficient information. PET-CT is indicated for suspected metastases based on CT or MRI data in cases where their confirmation fundamentally changes treatment tactics. In addition, PET-CT is mainly used to evaluate the results of antitumor treatment. The results of a molecular genetic study influence the choice of targeted therapy for a predominantly metastatic process in RC. Indicators of detection and accurate staging of early RC can be improved using endoscopic optical assessment and imaging techniques such as high-resolution MRI, contrast-enhanced endocrine ultrasound and PET-CT.