The article briefly considers physiological aspects of the human gut microbiota, associations between dysbiosis and colorectal cancer (CRC), disturbance of immune system in CRC, mechanisms of avoidance of immune surveillance by tumors, genetic instability in CRC, collisions and perspective of immunotherapy of CRC.

In the era of personalized treatment, oncologists are striving to tailor medical treatment to the characteristics of the individual patient, emphasizing the importance of a continuous search for accurate biomarkers. Prognostic biomarkers reflect the intricate underlying biology that enables cancer to progress. Intratumoral heterogeneity includes genetic, epigenetic and functional heterogeneity. Genetic intratumoral heterogeneity is a consequence of clonal evolution and a cause of disease progression. During the oncogenesis process, genetic aberrations accumulate continuously, result of this process is that tumors are genetically heterogeneous, with a plurality of coexisting clones that vary over time. Herewith specific mutations are associated with particular stages of tumor development, correlates with specific histopathological disease stages. Many patients with colorectal cancer have disease recurrence after resection of the tumor despite adjuvant therapy, while some patients don’t have a relapse despite the absence of treatment. Identifying reliable predictors of outcome after resection is a universal problem. So the reassessment of the current criteria and better prognostic and predictive biomarkers for the selection of patients who might benefit from adjuvant chemotherapy are urgently needed. A prognostic biomarker reflects the natural history of the tumor and provides information on the likely outcome and prognosis, independent of a specific treatment. Predictive biomarkers indicate the sensitivity or resistance of the tumor to a given treatment. Some markers can be both prognostic and predictive. Gene mutations and epigenetic aberrations that modify the intracellular signaling pathways may be important factors in oncogenesis. In this context, oncogenes, genes – tumor suppressors and small non-coding RNA have attracted attention as potential biomarkers and regulators of oncogenesis and evaluate in clinical trials.

Objective: retrospective evaluation of the results of the 2nd stage of implemented colorectal screening program by colonoscopy.

Materials and methods. In 2015–2017, The Department of Health of the Tyumen region is implementing a colorectal screening program. First stage of the program: the test for occult blood, 2nd stage: screening colonoscopy.

Results. Achieved 2157 screening colonoscopies for patients aged 55–65 years with a positive fecal immunochemical test for fecal occult blood. In 531 (24.6 %) patients adenoma and adenocarcinoma of the rectum and colon were revealed (adenomas verified in 365 (23.1 %) cases, adenocarcinoma – in 33 (1.5 %) cases). Of the total number of verified neoplasia (618 cases of localization), 365 (59 %) cases of adenoma and adenocarcinoma were located in the rectum and sigmoid colon, 253 (41 %) cases – in the descending colon, transverse colon, ascending colon and cecum.

Conclusions. In the completed study, the fecal immunochemical test and, with a positive result, a video-colonoscopy were performed at the 1st stage of colorectal screening for patients aged 50–65 years. In 98 % of cases, intubation of the cecum and the time of colonoscope removal for at least 6 minutes allowed to obtain a value of adenoma detection rate ~25 %, which is indicator of the effectiveness of the performed colorectal screening.

Objective: to evaluate the efficacy and safety of a new method for restoration of intestinal continuity after Hartmann procedure in patients with rectal cancer.

Materials and methods. We analyzed the results of reconstructive surgeries in patients that underwent obstructive resection of the rectum for rectal cancer between 1991 and 2011. We included patients with a rectal stump located under the pelvic peritoneum (its mean length was 8 (4–11) cm). All study participants underwent modified Duhamel procedure. We evaluated demographic characteristics of patients, as well as early and late postoperative complications.

Results. A total of 9 patients were treated with this method. Median time between the resection and reconstructive surgery was 13.2 months; median surgery duration was 255 min; median blood loss was 800 mL. One patient had an intraoperative complication (spleen injury). Early postoperative complications were observed in 2 (22.2 %) participants; of them, 1 (50 %) patient had necrosis of the brought-out bowel. One patient (11.1 %) developed anastomosis stricture 6 months post surgery.

Conclusion. We developed a new method to restore intestinal continuity after Hartmann procedure. None of the patients had complications associated with rectal stump isolation. The efficiency of this method should be confirmed by larger studies.

Objective: to develop an effective, well-tolerated, convenient for outpatient care (without installing a subclavian catheter) three-component treatment regimen that includes ftorafur – an original oral fluoropyrimidine drug.

Materials and methods. The study included 25 patients with disseminated colorectal cancer that have never received specific pharmacotherapy. We evaluated the efficacy and safety of a new first-line three-component treatment regimen with oxaliplatin + irinotecan + ftorafur. Patients in group 1 (n = 6) received this regimen for 3 weeks, whereas patients in group 2 (n = 19) received it for 2 weeks.

Results. Only preliminary results of the study are currently available. Median time to progression and overall survival are not yet estimated. Three (50 %) patients from group 1 achieved partial regression of metastases; 3 patients from this group had long-term (≥6 months) disease stabilization. Therapeutic effect (partial remission + long-term stabilization) was observed in all patients. Time without progression varied between 6 and 20 months. In group 2, therapeutic effect was estimated in 18 patients that received at least 2 courses of chemotherapy. Eight out of these 18 patients had partial response (2 of them underwent radical surgery); 8 patients had disease stabilization. Thus, 88.8 % of patients from group 2 responded to treatment. In the whole study population (both groups), response to treatment was achieved in 91 % of patients.

Conclusion. Our preliminary results suggest that the combination of oxaliplatin, irinotecan and ftorafur is safe and has an acceptable toxicity profile; therefore, it can be used in weakened patients.

Background. One of the reasons of the small intestinal bacterial overgrowth syndrome (SIBOS) is excision of a bauginiyev valve at a rightsided hemicolectomy both in planned and in the emergency order that demands not only restoration of continuity of an intestinal tube, but also a restore of the lost function of the ileocecal valval system.

Objective: to develop safe, effective and generally available areflux thin-colonic anastomoses for use in planned (primary anastomosis) and emergency (delayed compression anastomosis) surgery.

Materials and methods. New ways of formation the areflux thin-colonic anastomoses in the conditions of the emergency and planned surgery for prophylaxis of development of the SIBOS in a small intestine are suggested. The efficacy of the anastomoses is confirmed by the hydrogen breathing test.

Results. A right-sided hemicolectomy at 20 patients with primary anastomosis without areflux structure resulted in 60 % of cases to development of SIBOS in a small intestine, at 19 patients with primary anastomosis with formation of the areflux structure reduced risk of development of the SIBOS to 16 %. When forming of the delayed areflux compression thin-colonic anastomosis by the author’s technique the SIBOS did not develop at 72 % of patients.

Conclusions. Bauginiyev valve is an important structure of the human body, whose areflux function must be modeled when right-sided hemicolectomy is performed.

In the article we describe our experience treating a patient with a giant solitary fibrous tumor of the small pelvis. Since the tumor was highly vascularized, the patient underwent preoperative embolization of the vessels perfusing the tumor to reduce the risk of intraoperative blood loss.