Parametrium is a unique structure. Its definition has undergone significant changes throughout the evolution of concepts on the anatomy, embryology, and surgery of the pelvis. Knowledge of the parametrium anatomy is very important not only for surgeons dealing with the female reproductive system, but also for surgeons involved in the treatment of rectal cancer. For example, an outdated anatomical term “lateral ligaments of the rectum” is still widely used by gynecologic oncologists and is considered as a part of the parametrium. Combination surgeries for rectal cancer in women often involve the structures of parametrium. This paper reviews the history of studying the parametrium, its embryology, evolution of anatomical concepts, and their association with the development of pelvic surgery. We also propose allocating additional layers of the parametrium in order to make anatomical description closer to surgical practice.

This review analyzes clinical significance of Bax biomarker in colorectal cancer. We cover the most important characteristics of this protein, describe its role in the apoptosis regulation mechanisms, and asses its prognostic value. Despite the fact that multiple studies have significantly improved our knowledge of Bax expression in colorectal cancer, its impact on the disease prognosis remains poorly understood. Many issue related to its correlation with clinical and morphological characteristics of the tumor still have to be clarified.

Objective: to assess the effect of preoperative treatment option on the number of sphincter-preserving operations (SPO) in patients with low rectal cancer.

Materials and methods. The patients with low rectal cancer (0—6 cm from anocutaneous line) were randomized into 3 groups: in the 1st control group surgery was performed in 0—3 days after completion of short-course radiotherapy (5 х 5 Gy). Patients in the 2nd control group received identical radiotherapy but the interval before surgery was extended to 42 ± 3 days. Patients in the study group received treatment identical to 2nd control group with 2 additional courses of monochemotherapy with capecitabine, starting on the first day of radiotherapy. The primary endpoint was the number of SPO. Complete pathomorphologic response rate, overall survival, tumor-specific survival and event-free 5-year survival were also assessed as secondary endpoints.

Results. Data on 129 patients was analyzed: 46 in the 1st control group, 43 in the 2nd control group, 40 in the study group. The proportion of SPO was 41,3 ± 7,3 % in the 1st group, 69,7 ± 7,0 % and 77,5 ± 6,6 % in the 2nd group and study group, respectively. Complete histological response was achieved in 15 % of patients in study group, comparing to 14,3 % of patients in the 2nd group. Overall 5-year survival in this study was estimated to be 77,8 ± 4,5%, tumor-specific survival — 89,7 ± 3,7 %, event-free survival — 90,1 ± 2,9 %, with no significant differences between groups.

Conclusion. Short-course radiotherapy (5 х 5 Gy) with 6-week interval before surgery resulted in increase of SPO rate with no affect on oncologic outcome.

Objective: to analyze the efficacy of a newly developed method for the treatment of radiation-induced rectovaginal fistulas using autologous adipose tissue obtained by aspiration liposuction.

Materials and methods. This retrospective study included 24 patients with radiation-induced rectovaginal fistulas that arose after chemoradiotherapy for malignant tumors of the female reproductive system. All patients underwent colostomy before treatment initiation. Study participants received 1 to 5 injections (mean number 3) of autologous adipose-derived regenerative cells. The main indication for the procedure was the presence of a fistula, diagnosed at least 6 months after the last course of radiation therapy. We evaluated time to fistula healing, results of elastometry, and presence of complications.

Results. The mean total dose received by patients during their radiotherapy was 60 Gy; median time to initiation of fistula treatment was 15 months. Before the injection of adipose-derived regenerative cells, the mean fistula diameter was 2.50 + 0.46 cm, whereas after 3 months, it reduced to 1.35 + 0.47 cm and after 6 months, it was 1.12 + 0.47 cm. All patients had complete epithelialization of the defect. No cases of fistula recurrence were registered.

Conclusion. We demonstrated high efficacy of a new reconstructive method for radiation-induced rectovaginal fistulas with autologous adipose tissue obtained by aspiration liposuction. Its effectiveness is confirmed by complete fistula closure and restoration of intestinal continuity in all study participants.

Objective: to determine the minimum number of lymph nodes (LN) required for accurate prediction of overall survival in patients with stage II colon cancer and to assess the prognostic value of criteria used in the MOSAIC trial.

Materials and methods. This retrospective study included patients with stage II colon cancer that underwent surgical treatment in the Department of Proctology and received adjuvant chemotherapy (if needed) in the Department of Clinical Pharmacology and Chemotherapy of N.N. Blokhin National Medical Research Center of Oncology between 2004 and 2013. Overall survival was considered as the main criterion of treatment efficacy.

Results. A total of 445 patients met the inclusion criteria; of them, 60 (13.5 %) patients received adjuvant chemotherapy. The receiver operating characteristic (ROC) analysis was employed to evaluate the predictive value of the number of removed LN for disease progression and death in patients with stage II colon cancer. We found that specificity of >80 % was achieved by removing/examining at least 12 LN. The examination of 13 LN increases specificity by another 6 %. Further increase in the number of removed/examined LN (>13) did not significantly improve prognostic accuracy for death from the moment of disease progression. Only the removal of 13 or more LN ensured a significant impact on overall survival (hazard ratio (HR) 0.12; 95 % confidence interval (CI) 0.02—0.91; p = 0.04). At multivariate analysis, the following factors were found to affect overall survival: postoperative complications (HR 2.4; 95 % CI 1.4—4.3; p <0.01), pT4 stage (HR 1.2; 95 % CI 1.003—1.400;р = 0.04), and removal/examination of 13 or more LN(HR 0.1; 95 % CI 0.02—1.01;p = 0.05). However, after the inclusion of the variable reflecting the number of factors form the MOSAIC trail into the multivariate model, the last 2 covariates lost their statistical significance as independent prognostic factors.

Conclusion. We recommend removing/examining at least 12 (preferable 13) LN in patients with stage II colon cancer in order to ensure proper staging. For patients with high risk of disease progression (those with <13 LN removed and/or presented a T4 depth of invasion in the intestinal wall), adjuvant chemotherapy should be considered. For routine clinical practice, we recommend assessing the risk of progression using the criteria from the MOSAIC trial for patients with stage II colon cancer.

Objective: to evaluate the prognostic value of Bax expression in the primary colon tumor of patients with metastatic colorectal cancer (mCRC) receiving first-line treatment with a triple combination of irinotecan + oxaliplatin + long-term infusion of 5-fluorouracil.

Materials and methods. The study included patients with mCRC (morphologically (histologically) verified diagnosis of colonic adenocarcinoma) that have never received treatment for disseminated disease. Study participants received a new first-line treatment regimen with a triple combination of irinotecan + oxaliplatin + long-term infusion of 5-fluorouracil. We evaluated both short-term and long-term treatment outcomes. We also assessed the level of Bax expression in primary tumor samples (biopsy/surgery specimens) collected prior to initiation of first-line treatment using immunohistochemical methods. We analyzed the correlation between the levels of Bax expression and short-term/long-term treatment outcomes.

Results. Seventeen out of 20 mCRC patients included in the study were tested for Bax expression in the primary tumor using immunohistochemical staining. The analysis of correlation between Bax expression in tumor tissue and time-to-progression in patients with mCRC receiving first-line treatment with a triple combination of drugs demonstrated that high Bax expression was a favorable prognostic factor associated with longer time-to-progression. Median time-to-progression was significantly longer in patients with Bax overexpression than in those with low levels of Bax expression or no expression: 15.7 15,7 ± 3.38 months vs 8.6 15,7 ± 0.6 months, р = 0.012. When analyzing the impact of Bax expression on the overall survival (OS) in patients with mCRC, we found that patients with Bax overexpression demonstrated better OS (median follow-up time 17.3 15,7 ± 2.54; OS was not reached; mean value 31.26 15,7 ± 2.85 months) than patients with low Bax expression or no expression (median OS 13.60 15,7 ± 3.03 months), p = 0.021.

Objective: to evaluate the possibilities of conservative treatment of patients with complications of colorectal cancer.

Materials and methods. The study included the results of treatment of 105 patients with complications of colorectal cancer treated on the basis of the District Clinical Hospital of Surgut for the period 2012—2017. Of these, 86 (81.9 %) patients with acute obstructive intestinal obstruction, 11 (10.5 %) patients with bleeding from colon tumors, and 8 (7.6 %) patients with purulent-septic complications of colon cancer.

Results. The complex of conservative measures, including colon stenting, provides restoration of the passage through the digestive tract in 79.1 % of patients, which allows preparing the patient to perform surgery, thereby reducing the risk of complications. Twenty-eight (27.6 %) patients were operated on an emergency basis: due to the lack of effect from conservative therapy for acute intestinal obstruction — 18 (17.1 %) patients, due to peritonitis — 8 (7.6 %), due to recurrent colonic bleeding — 3 (2.9 %) patients. The death rate was 13.8 % (n = 4). In the delayed order after successful conservative therapy, 70 (66.7 %) patients underwent surgical treatment in the surgical and oncology departments. Postoperative mortality was 1.4 % (n = 1).

Conclusion. The complex of conservative measures, which allows avoiding emergency surgical intervention at the urgent stage of treatment, is the basis for carrying out a full-fledged surgical intervention in a delayed procedure in a specialized hospital, observing the principles of oncological radicalism.

Objective: to analyze the frequency of metastasectomy in general population of patients with RAS wild-type metastatic colorectal cancer who received chemotherapy and anti-EGFR monoclonal antibodies

Materials and methods. This prospective, non-randomized, multicenter study was designed to evaluate the frequency of resections of organs affected by metastasis. Our statistical hypothesis was that the addition of anti-EGFR antibodies should increase the frequency of metastasectomy from 5% to 15 %. Sample size calculations showed that to obtain a power of 80 % and an alpha level of 0.05 to detect the difference, we would need to recruit 50 patients. The primary endpoint was the frequency of resections of organs affected by metastasis, whereas the secondary endpoints included objective response rate, progression-free survival, and length of live. Tolerability of the therapy was analyzed separately.

Results. Eighteen out of50 (36 %) patients achieved objective response; 32 (64 %) patents achieved stable disease and 18 (36 %) patients had disease progression. Radical resection of organs affected by metastasis was performed in 8 out of 50 patients (16 %): 1 individual had lung resection and 7 individuals had liver resection. Among participants with isolated liver lesions, the frequency of metastasectomy was 24 % (6 out of 25 patients). At a median follow-up of 14 months (between 1 and 34 months), median progression-free survival was 8 months (95 % confidence interval 6.2—9.8) and median length of life was 26 months (95 % confidence interval 19.7—32.2). The estimated 2-year overall survival was 83 % in patients who underwent metastasectomy vs. 51 % in those who had no metastasectomy.

Conclusions. The addition of anti-EGFR monoclonal antibodies to standard combination chemotherapy (FOLFOX/FOLFIRI) increases the frequency of metastasectomy in patients with non-resectable metastatic colorectal cancer, which results in an increased length of life.