Introduction. When providing specialized medical care to patients with malignant neoplasms (MN), there is a problem of detecting synchronous and metachronous oncological diseases. It seems logical to conduct a quantitative FIT test (Fecal immunochemical test) for all patients with extra-colonical MN, followed by a colonoscopy in the case with a positive result. The purpose: To analyze the experience of organizing the detection of colorectal cancer in providing specialized medical care to patients with malignant neoplasms of other localization. Materials and methods. The study involved 639 patients with extra-colonical MN, who underwent a quantitative FIT test. Results. In the study group of patients 6 colorectal MN, 25 cases of precancerous pathology, and 16 cases of non–cancerous pathology of the large intestine were detected. All patients with colorectal cancer (CRC) had a positive FIT test, the quantitative value of the test results exceeded 501 ng/ml. The FIT test for non-epithelial and secondary hypertension without mucosal involvement was 0 ng/ml. In the group of FIT–positive patients, 2.6 times more cases of dysplasia were detected than in FIT–negative patients. Among patients with tumor and precancerous colorectal pathology, oncourological was the leading localization of extracolonical cancer - 41.9% (13 cases: 4 adenomas, 3 CRC, 6 dysplasia). The FIT test result was strongly associated with the localization of an extra-colonical tumor (C=0.831, p