Objective: to assess short-term and long-term outcomes of right hemicolectomy with extensive lymph node dissection using the experience of one clinic.

Materials and methods. This retrospective study analyzed data from a prospectively collected database containing information on all patients with right-sided colon cancer that underwent laparoscopic right hemicolectomy with D3 lymph node dissection between 2013 and 2018. We estimated intraoperative blood loss, surgery duration (taken from anesthetic records), frequency of postoperative complications, length of in-hospital stay, duration of lymphorrhea, time to gastrointestinal recovery, integrity of the mesocolon, number and location of removed lymph nodes.

Results. A total of 50 underwent laparoscopic right hemicolectomy with D3 lymph node dissection. No cases of surgical conversion were registered. Median surgery duration was 185 min; median blood loss was 30 mL. No postoperative mortality was observed in the study cohort. Twelve (24 %) patients had postoperative complications; 2 (4 %) patients underwent repeated surgery. Median number of lymph nodes examined was 26; high-quality specimens (G ) were obtained in 48 (96 %) patients. At a median follow-up of 19.5 months, 2 (4 %) patients had disease progression (developed liver metastases).

Conclusion. Our results confirm safety of laparoscopic approach for right colon resection with D3 lymph node dissection

Background. The effect of anastomotic leakage (AL) on oncological outcomes after total mesorectumectomy is controversial.

Objective: to investigate the influence of AL and other factors on oncological outcome.

Materials and methods. Data of 67 patients underwent total mesorectumectomy with normal healing were compared with those for 16 patients who experienced AL. Long-term oncological outcomes were analysed.

Results. Median follow-up was 43 months. AL rate was 19.4 % (16 cases out of 83). Following factors had negative influence on lower 4-year disease-free survival rate and reached statistical significance in univariant analysis: tumor invasion (hazard ratio (HR) 8.8; 95 % сonfidence interval (CI) 1.4–13.7; р = 0.01), metastases in regional lymph nodes (HR 3.5; 95 % CI 1.2–12.3; р = 0.03), tumor stage (р = 0.048), level of tumor differentiation (HR 0.1; 95 % CI 0–0.6; р <0.0001), tumor stenosis (HR 8.8; 95 % CI 1.4–13.7; р = 0.002), AL (HR 3.9; 95 % CI 1.6–37.1; р = 0.01). In the logistic regression analysis independent risk factors for the development of recurrence were not revealed.

Conclusion. AL was not proved to be a risk factor of worse oncological outcome. Hence, additional adjuvant treatment or extended follow-up on the basis of the occurrence of AL after low anterior resection of rectal cancer might not be justified.

Objective: to evaluate the prognostic value of clinical and pathomorphological stages in patients with rectal cancer after preoperative chemoradiotherapy and to assess the effectiveness of adjuvant chemotherapy in these patients.

Materials and methods. We conducted a retrospective analysis of the data from a prospectively maintained database for patients with rectal cancer. The study cohort included patients with stages I–III rectal cancer that underwent preoperative chemoradiotherapy followed by surgical treatment performed in the Department of Proctology and Clinical Pharmacology and Chemotherapy between 2004 and 2013. The relapse-free and overall survival rates were assessed to estimate treatment efficacy.

Results. A total of 457 patients were eligible for the study; of them 98 patients (21.4 %) received adjuvant chemotherapy. The following independent factors were found to negatively affect relapse-free survival: perineural invasion (р <0.01; hazard ratio (HR) 3.1; 95 % confidence interval (CI) 1.43–6.89), preoperative neutrophil-lymphocyte ratio ³3 (р = 0.01; HR 1.8; 95 % CI 1.37–2.42) and pathomorphological stage (р <0.01; HR 1.82; 95 % CI 1.37–2.42) (but not clinical stage). The pathomorphological stage (р <0.01; HR 1.9; 95 % CI 1.30–2.65), invasion into lymphatics (р <0.01; HR 2.4; 95 % CI 1.27–4.59) and white blood cell count ³11 000/µL (р <0.01; HR 13.1; 95 % CI 1.33–7.33) were independently associated with poorer overall survival. We observed a trend towards a decline in the relative risk of death in patients with stage yp3N0M0 cancer in response to adjuvant chemotherapy (р = 0.1; HR 0.4; 95 % CI 0.01–37.6). There was also a trend towards better relapse-free and overall survival in adjuvant chemotherapy-treated patients with stage ypT0–4N1–2 (р = 0.1; HR 0.65; 95 % CI 0.4–1.1 and р = 0.3; HR 0.3; 95 % CI 0.4–1.4 respectively) and stage yрT0–4N2M0 (р <0.01; HR 0.3; 95 % CI 0.14–0.70 and р = 0.03; HR 0.5; 95 % CI 0.2–1.0) cancer.

Conclusion. In patients with rectal cancer, the pathomorphological stage appears to be a more reliable prognostic parameter compared to the clinical stage; this should be considered when prescribing adjuvant chemotherapy to patients that underwent preoperative chemoradiotherapy.

Objective: to assess the efficacy of anti-angiogenic agents incorporated into second-line chemotherapeutic regimens for metastatic colon cancer depending on the KRAS gene mutation status.

Materials and methods. We selected completed prospective randomized controlled phase III clinical trials evaluating the efficacy of antiangiogenic agents (bevacizumab, ramucirumab and aflibercept) added to second-line chemotherapy for metastatic colon cancer with subanalysis of treatment efficacy depending on the KRAS gene mutation status. Meta-analysis was performed using the ReviewManager (RevMan) v. 5.3 (The Cochrane Collaboration, Denmark).

Results. Three studies (ML18147, RAISE, VELOUR) involving 2165 patients (1137 with KRAS wild-type tumors and 1028 with KRAS-mutant tumors) met the inclusion criteria and were included into this meta-analysis. The majority of patients (84 %) received bevacizumab in the first-line treatment. The results of our meta-analysis suggest that adding an anti-angiogenic drug to chemotherapy in patients with KRAS wildtype colon cancer significantly improved both progression-free survival (hazard ratio (HR) 0.71; 95 % confidence interval (CI) 0.62–0.80; р <0.00001; I2 = 22 %, p = 0.21) and overall survival (HR 0.76; 95 % CI 0.66–0.88; р = 0.0001; I2 = 0, p = 0.59). In patients with KRASmutant colon cancer, incorporation of an anti-angiogenic drug into the treatment regimen was not associated with better overall survival (ОР 0.9; 95 % CI 0.79–1.03; р = 0.11; I2 = 0, p = 0.98), although improved progression-free survival (HR 0.78; 95 % CI 0.68–0.89; р = 0.0002; I2 = 0, p = 0.46). Conclusion. Continuation of anti-angiogenic therapy in the second-line treatment for metastatic colon cancer is most effective in patients with KRAS wild-type tumors. In individuals with KRAS-mutant tumors, continuation of bevacizumab or switch to another anti-angiogenic agent in the second-line treatment improves progression-free survival and has a statistically insignificant effect on overall survival.

Objective: to evaluate five-year overall and relapse-free survival in patients with complicated rightand left-sided colon cancer that underwent emergency resection.

Materials and methods. The study included 501 patients with urgent complications of rightand left-sided colon cancer that underwent emergency resection. The data was obtained from an electronic register containing the information on patients with urgent complications of colorectal cancer treated in general and specialized surgical hospitals in Smolensk between 2001 and 2013 (13 years). We assessed fiveyear overall and relapse-free survival in these patients.

Results. A total of 501 resections were performed during the study period. We observed significant differences in resection statuses of patients after emergency resection: the R1 resection status was more frequent in individuals with right-sided colon cancer compared to those with left-sided colon cancer (20.8 % vs. 6.9 %, p = 0.0002). Mean number of lymph nodes examined was 4.6 ± 2.0 in patients with right-sided cancer and 5.3 ± 3.0 in patients with left-sided cancer (p = 0.18). There were no differences in the number of patients receiving adjuvant treatment between the groups (p = 0.11). Patients with left-sided stage II/IIIB/IIIС complicated colon cancer demonstrated better overall and relapse-free survival than those with right-sided tumors of the same stages (overall survival: p = 0.007, p = 0.0002, p = 0.0001 for stages II, IIIB, IIIС respectively; relapse-free survival: p = 0.005, p = 0.0003, p = 0.0002 for stages II, IIIB, IIIС respectively).

Conclusion. The observed differences in the outcomes of treatment for rightand left-sided complicated colon cancer can be explained by the fact that the majority of emergency resections for right-sided tumors were one-stage and were performed in general surgery hospitals. Patients with left-sided cancer underwent tumor removal on the second stage more often than those with right-sided cancer (32 % vs. 13 %). Treatment of patients with complicated colon cancer should be consistent, stepwise, and pathogenetically reasonable.

Background. Malignant colonic obstruction (MCO) it is one of the most common and severe complications of colon and rectal cancer. The mechanisms underlying MCO development include impairments in motor, secretory and resorptive functions of the intestine, disorders of water-electrolyte metabolism, endotoxicosis, and compartment syndrome. All of these conditions significantly reduce patient survival.

Objective: to compare the outcomes of colonic stenting in patients with primary and secondary tumors and to assess the efficacy of surgical treatment.

Material and methods. This retrospective study included 149 patients with MCO caused by both primary colon tumors and secondary compression or extra-colon tumors. All patients underwent X-ray guided colonic stenting in the N.N. Blokhin National Medical Research Center of Oncology between 2013 and 2017.

Results. Primary technical success was achieved in 143 (96 %) patients, whereas overall technical success (including restenting) was achieved in 144 (96.6 %) patients. A total of 121 (84 %) patients demonstrated complete clinical success, while 23 (15.98 %) patients had partial clinical success. The efficacy of stenting was significantly higher in patients with primary colorectal cancer than in patients with secondary lesions of the colon (96.7 % vs. 27.3 %; p <0.0001).

Conclusion. Stenting is a safe and effective method of comprehensive treatment for patients with colon cancer and signs of MCO. It expands the scope of palliative care for disseminated cancer. However, in patients with extra-organ compression and secondary lesions of the colon, this procedure remains largely ineffective.

Objective: to evaluate therapeutic pathomorphosis and Tand N-downstaging in response to various polyradiomodification regimens used in the combination therapy for rectal cancer.

Materials and methods. A total of 241 patients received combination therapy for rectal cancer using 4 different polyradiomodification regimens. We assessed therapeutic pathomorphosis and tumor downstaging in these patients. Eighty-two participants (34 %) underwent polyradiomodification with a 14-day course of capecitabine (Cap) given in a therapeutic dose (2 g/m2body surface) (Cap14 + metronidazole (MZ) and Cap14 + MZ + microwave hyperthermia (MW-HT)), whereas the remaining 159 participants (66 %) underwent polyradiomodification with a 5-day course of Cap in a radiosensitizing dose (1.5 g/m2 body surface) (Cap5 + MZ and Cap5 + MZ + MW-HT).

Results. Grade IV therapeutic pathomorphosis was observed in 19.5 % of patients treated with a 14-day course of Cap (Cap14 + MZ and Cap14 + MZ + MW-HT) and 1.3 % of patients treated with a 5-day course of Cap (Cap5 + MZ and Cap5 + MZ + MW-HT) (p = 0.00001). Patients receiving a 14-day course of Cap demonstrated T-downstaging significantly more often than those receiving a 5-day course (41.5 % compared to 9.4 % respectively, p = 0,00001). Regression of regional lymph node metastases was diagnosed in 51.1 % of patients from the Cap14 group only.

Conclusion. Our findings suggest that grade III–IV therapeutic pathomorphosis and tumor downstaging are more frequently achieved in polyradiomodification regimens with a 14-day course of Cap at a dose of 2 g/m2 (Cap14 + MZ and Cap14 + MZ + MW-HT).