Objective: to compare the efficacy and tolerability of second‑line chemotherapy with original bevacizumab (Avastin) and biosimilar bevacizumab produced by “Biocad” (Avegra) in patients with metastatic colon cancer.
Materials and methods. This retrospective observational study included patients with metastatic colon cancer treated in 9 clinics in the Russian Federation. Inclusion criteria were as follows: metastatic or locally advanced colon cancer and second‑line therapy with bevacizumab (Avastin or Avegra). The primary outcome measure was overall survival (OS). Secondary outcome measures included progression‑free survival (PFS), disease control rate (DCR), and incidence of adverse events associated with antiangiogenic therapy.
Results. We identified 209 patients with metastatic colon cancer who received second‑line therapy with biosimilar bevacizumab (n = 37; 17.7 %) or original bevacizumab (n = 90; 43 %) or no targeted therapy (n = 82; 39.3 %) between 2014 and 2018. Patients in these three groups were matched for their main prognostic characteristics. The DCR was 59.5 % in the group of biosimilar bevacizumab, 58.9 % in the group of original bevacizumab, and 50 % in the control group (without targeted therapy). PFS was 6 months in the chemotherapy group and 8 months in the groups of bevacizumab (hazard ratio (HR) 0.77; 95 % confidence interval (CI) 0.65–0.91; p = 0.002); the difference in PFS between patients receiving biosimilar bevacizumab and original bevacizumab was insignificant (HR 1.3; 95 % CI 0.81–2.1; р = 0.3). Median OS was 16 months in the chemotherapy group, 30 months in the biosimilar bevacizumab group, and 20 months in the original bevacizumab group (HR 0.89; 95 % CI 0.72–1.1; р = 0.3). We observed a tendency to longer OS in patients receiving biosimilar bevacizumab (HR 0.44; 95 % CI 0.17–1.1; р = 0.08). Bevacizumab‑ associated toxicity was limited to arterial hypertension and was registered in 4 patients with only one patient who developed grade III hypertension.
Conclusions. There was no significant difference in PFS between patients receiving biosimilar and original drug, while OS was higher in the group of biosimilar bevacizumab. Both medicines demonstrated similar toxicity. Therapy with biosimilar bevacizumab ensured lower incidence of hypertension and proteinuria compared to the original drug. An additional prospective observational study assessing the efficacy and tolerability of biosimilar bevacizumab in colon cancer patients is needed.

Objective: to analyze factors affecting the mortality of patients who have undergone emergency surgeries for complicated colorectal cancer.
Materials and methods. In this retrospective study, we evaluated treatment outcomes of 112 patients who underwent surgeries for complicated colorectal cancer in 3 clinical hospitals of Smolensk between 2014 and 2019. We included patients with moderate or severe disease (ASA II or III) who have undergone emergency resections for intestinal obstruction or tumor perforation. We assessed clinical, laboratory, and tumor‑associated factors affecting postoperative mortality.
Results. Patients’ gender had no significant impact on postoperative mortality (p = 0.69). Mean age of study participants was 65 years (range: 43–86 years). Age also did not affect postoperative mortality; most of the patients both among those died (n = 19) and survived (n = 93) were older than 60 years (p = 0.46). We observed no significant correlation between tumor location and postoperative mortality (p = 0.27). Of 19 patients with lethal outcomes, five died due to pulmonary embolism. They have elevated level of D‑dimer, which was significantly higher than that in survivors (p = 0.014). The lowest mortality was observed in patients who have undergone two‑stage surgeries with tumor removed at the second stage compared to patients operated on using other techniques (p = 0.041). Using multivariate logistic regression, we identified independent factors that affected mortality. They included: tumor perforation (odds ratio (OR) 2.8; 95 % confidence interval (CI) 1.2–7.6; p = 0.003), severe comorbidity (OR 1.6; 95 % CI 1.7–8.2; p = 0.02), D‑dimer level >510.1 ± 10.2 ng/L (OR 1.5; 95 % CI 1.3–4.5; p = 0.01), type of surgery, namely resections with primary anastomosis formation and two‑stage surgeries with tumor removal at the first stage (OR 1.2; 95 % CI 1.1–6.3; p = 0.04).
Conclusions. Tumor perforation, cardiovascular disease in combination with other comorbidities, type of surgery (resections with primary anastomosis formation and two‑stage surgeries with tumor removal at the first stage), and elevated preoperative level of D‑dimer had the most significant impact on postoperative mortality.

Objective: identification and description of clinical and morphological characteristics of rare forms of stromal cell tumors of the ovaries.
Materials and methods. Retrospectively processed over 10 thousand case histories of patients with various ovarian tumors who were examined and treated at the N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of Russia and the National Center for Oncology and Hematology of the Ministry of Health of Kyrgyz Republic. In 473 patients were diagnosed stromal cell tumors, among them 3 cases of rare forms of tumors of the stroma of the sex cord were identified: stromal tumor from Sertoli cells, malignant luteoma of the ovary, lipid‑cell tumor from Leydig cells. All patients underwent a planned morphological study of surgical material and immune-histochemical study.
Results. The detailed data of clinical observations of rare types of tumors, which was presented in the literature by isolated cases, are presented, the description of which in the literature is presented by isolated cases. The possible effect of clinical and morphological characteristics on the survival of patients with rare forms of stromal cell tumors of the ovaries were analyzed.
Conclusions. The necrobiotic changes in the tumor, the degree of malignancy, and the stage of the disease are potential predictors of poor prognosis in patients with rare forms stromal cell tumors of the ovaries which require confirmation in a larger sample of patients.

Rectal fistula – one of the most common coloproctological diseases. Annually, thousands of patients with anal fistula have had treated around the world. Treatment of this disease is an actual problem in coloproctology nowadays due to the high frequency of recurrence and anal incontinency. The chronic persistent perianal suppuration and multiple surgical interventions the main predictor of emergence of the anal incontinence, which could be achieve almost 50 %, according the literature data. The risk of emergence the anal incontinence is particularly high in the treatment of complex fistulas. Therefore, the problem of complex rectal fistulas treating remains an actual task in the clinical practice of a coloproctologist.

This article explores evolution of treatment options in colorectal cancer with synchronous metastatic disease, role of surgical approach on different stages of combined‑modality therapy, including “liver first” strategy. Prospects of perioperative and neoadjuvant polychemotherapy in patients with colorectal cancer with synchronous distant metastases to liver, data on possibility of using radiation therapy in treatment of primary tumor and liver metastases, as well as risks and benefits of this approach and available clinical research data are analyzed.