Purpose of the study. To represent the results of a two-stage surgical treatment in patients with extensive pelvic bone defects.
Materials and methods. Data on 7 patients who underwent surgery for pelvic and sacrum tumors at the National Medical Research Centre for Oncology from 2016 up to 2020 are presented. The average age of the patients was 36 years. Patients with massive tumors that required a major resection of the posterior pelvis and the formation of an extensive bone defect requiring reconstruction with massive allografts and implants were selected for the study. 5 patients underwent different variations of sacrectomies with the resection of the iliac bones; 2 patients – interiliac-abdominal resections. For all these patients, surgical treatment was split into 2 stages.
Results. At the first stage we performed: 5 surgical interventions (total or extended sacrectomy at L5–S1 with lumbar-iliac bilateral stabilization with an 8‑screw pedicle system) in patients with sacral tumors. In 2 cases, an interilio-abdominal resection with the defect replacement with cement articulating spacer. Intraoperative blood loss on average was 1.8L. We used autohemotransfusion to compensate the intraoperative blood loss.
The 2nd (reconstructive) stage was completed on average after 3 months. The reconstructive stage was not accompanied by major trauma in all patients. The average blood loss was approximately 800 ml. There were no complications after the reconstructive surgical stage.
Conclusion. The described two-stage technique allowed to avoid severe infectious complications requiring removal of implants and grafts in all patients. Adequate spinal pelvic stabilization and/or spacing of the defect contributed to early functional rehabilitation of patients and the continuation of adequate adjuvant therapy in the interstage period. The delaying of the reconstruction allowed to reduce the duration and invasiveness of the main intervention without affecting the final result of treatment.

Purpose of the study. To study the effect of SIEL 159–330 coating on the cell clusters formation rate in a hanging drop method in combination with the use of methylcellulose (MC) and collagen as cell aggregation improving agents.
Materials and methods. BT20 breast cancer cells were cultured in drops of 20 μL (104  cells per drop) on the lid of a polystyrene Petri dish coated with SIEL 159–330 silicone elastomer (GNIIKHTEOS, Moscow, Russia) or without coating. The study tested three concentrations of MC (0.1 %, 0.25 % and 0.4 %) and collagen (150 µg/ml, 300 µg/ml and 600 µg/ml). The rate of formation of cell conglomerates was assessed by evaluating their area after 4, 24, 48, and 72 hours of cultivation.
Results. The use of SIEL 159–330 coating made it possible to obtain spheroids of the same size as the addition of 0.4 % MC over a time interval of 72 hours. The silicone coating additionally reduced the size of cell spheroids in the medium with 0.1 % MC at all time points; however, this effect disappeared with increasing concentration of MC. In addition, the use of SIEL 159–330 reduced the relationship between the size of cellular spheroids and the concentration of MC, which allows us to consider the use of this coating as an alternative to MC or a way to reduce its concentration. In the experiment with the addition of collagen to the culture medium, the sizes of cell conglomerates formed on the silicone coating were significantly smaller than on uncoated plastic in all variants of the experiment and time points. The effect was more pronounced for a collagen concentration of 600 μg/ml. The use of SIEL 159–330 coating, in addition, reduced the variability in the size and shape of the resulting cell conglomerates.
Conclusion. Accelerated aggregation of cells and fibers of the extracellular matrix in hanging drops, as well as a reduction in the variability in the size and shape of the resulting cell clusters on SIEL 159–330, allows us to reduce the time of experiments and material costs, as in experiments with the addition of substances that accelerate the formation of spheroids (MC and collagen), as well as in their absence.

Ewing's sarcoma is the second most common oncological disease of bones and soft tissues in children and adolescents, which is characterized by rapid growth and early metastasis. Brain metastases (BMs) occur in 10–12 % of cases and constitute a factor in the unfavorable prognosis of the disease. The possibilities of surgical treatment are often limited by the localization of a metastatic tumor, and the vast majority of chemotherapy drugs don’t penetrate the blood-brain barrier, therefore radiation therapy, particularly stereotactic radiosurgery, the principle of which is a single high dose (15–24 Gy) of ionizing radiation to the pathological focus, is the most important method of treatment. High accuracy of tumor irradiation is ensured by rigid immobilization of the patient (using stereotactic frames or individual three-layer thermoplastic masks) in combination with positioning of the patient and control of his position by orthogonal X-rays. According to various authors, the use of stereotactic radiosurgery provides local control over BMs in 90 % of patients, regardless of the histological type of the primary focus, age and gender of the patient. The article describes a clinical case of successful radiosurgical treatment of a child suffering from extra-skeletal Ewing’s sarcoma, in which following the complex treatment, progression of the disease, represented by multiple metastatic brain damage was revealed; the cumulative volume of metastatic foci was 2.3 cm³ and due to the proximity of the brain stem, as well as in order to avoid exceeding the tolerant load on healthy brain tissues, the total focal dose did not exceed 16 Gy. A complete response to therapy in the form of regression of all foci was noted six months after the treatment. To date, insufficient data has been published on the use of stereotactic radiosurgery in pediatric oncology, but in the available literature, the authors demonstrate the effectiveness and safety of treatment. Further research is needed to study the effect of the radiosurgical method on the children.

The presented clinical case demonstrates the potential of medical technologies with organ replacement in the treatment for kidney cancer (KC) with a tumor thrombus located in the retrohepatic inferior vena cava (IVC) complicated by thromboembolism of the medium and small branches of the pulmonary artery (PATE). The treatment outcomes in such patients are usually poor due to a great number of complications and high mortality. The literature data estimates operative mortality rate of 13 %, and the frequency of early postoperative complications reaches 60 %. Standard approaches to anesthesia in case of thromboembolism and the threat of massive PATE are ineffective. In this clinical case, we chose the therapeutic tactics with extracorporeal membrane oxygenation (ECMO) in the intra- and early postoperative period in order to avoid or minimize life-threatening complications in the KC patient with a tumor thrombus in IVC and PATE. The effective use of ECMO minimized the risk of fatal complications during nephrectomy with thrombectomy for a malignant kidney tumor in the patient with pulmonary embolism and subcompensated disorders of the oxygen transport function of the lungs. The main objective of medical care for this patient involved both the radical treatment of kidney cancer and the elimination of a potential cause of thromboembolism of the pulmonary artery branches, fragments of hematogenous and tumor microthrombi. The total duration of ECMO was 30 hours. No significant complications in organs and systems were recorded during the surgery and in the early postoperative period. The development and implementation of new technologies, including devices for oxygen blood saturation and carbon dioxide elimination, undoubtedly gives a chance for a cure for cancer patients with decompensated organ and functional capabilities.

Hodgkin's lymphoma is a malignant disease of the lymphatic system. Hodgkin's lymphoma was first described by Dr. Thomas Hodgkin in 1832 and later named “Hodgkin's disease” by Samuel Wilkes. Hodgkin's lymphoma accounts for about 24 % of all lymphomas. Hodgkin's lymphoma is classified as classical and nodular lymphoid-predominant (Nodular type of lymphoidpredominant Hodgkin's lymphoma). Classical Hodgkin's lymphoma includes the following histologic variants: nodular sclerosis variant (types I and II), mixed cell variant, classic lymphocyte-rich variant, and rare lymphoid depletion variant. Epidemiological and serological studies showed the involvement of the Epstein-Barr virus into Hodgkin's lymphoma etiology, since its genome was found in the study of the biopsy material samples from patients with Hodgkin's lymphoma. A relationship with the human immunodeficiency virus (HIV) was revealed as well, and patients infected with HIV have a significantly increased risk of developing Hodgkin's lymphoma compared to healthy people. An in-depth study of the Hodgkin's lymphoma pathophysiology revealed new therapeutic targets in the treatment of this disease. All these discoveries changed the understanding of the Hodgkin's lymphoma pathogenesis, and were important for the development of new methods of treatment. The history of therapy begins on the cusp of the 19th and 20th centuries. Over the past four decades, achievements in radiation therapy and combined chemotherapy have significantly improved overall survival of patients with Hodgkin's lymphoma. Currently, more than 80 % of patients under 60 years old with first diagnosed Hodgkin's lymphoma can be cured from this disease after first-line chemotherapy.

Colorectal cancer (CRC) is a relevant issue of modern oncology and ranks the third place among most common malignancies. Every year, more than 1 million new cases of CRC are diagnosed worldwide, with approximately the same frequency of prevalence among the male and female population. Colon cancer (CC) amounts for more than half of all cases of CRC, and it’s incidence and mortality remain rather high.
Surgery remains the main method of CRC treatment, and determining the extent of surgery and lymph node dissection remains an urgent problem.
For the first time in Japan, a classification of groups of lymph nodes (l.n.) was proposed depending on the level of lymph outflow and location in relation to the main vessels. According to the numbering of l.n. groups by the Japanese Society for Cancer of the Colon and Rectum (JSCCR), all lymph nodes are numbered with three digits.
As a rule, lymphogenic metastasis occurs in one direction, bilateral spread is possible if the tumor is located at the same distance from two feeding vessels. With tumors of the right-sided localization, all groups of l.n. located along the branches of the superior mesenteric artery are removed, and with tumors of the left half of the colon, all l.n. located along the trunk of the inferior mesenteric artery are removed. The presence of affected l.n. is important for assessing the prognosis and further determining the need for adjuvant therapy. Some literature data demonstrate good results of surgical interventions performed in accordance with the concept of embryonic planes and complete mesocolonic excision. D3 lymph node dissection is not performed in daily practice in some European countries and North America, unlike a number of Eastern countries. However, the level of vessel ligation remains the subject of scientific discussion.
The purpose of this review was to analyze the available literature on the problem of choosing the level of lymph node dissection in CC surgery.

Experiments with small laboratory animals are required for better understanding of a disease flow, for studying the mechanisms of it’s development and for the development of new therapeutic strategies. A significant part of experimental studies involve anesthesia. In this regard, the choice of the optimal anesthesia protocol is an important point of research, since an inadequate depth of anesthesia or the influence of undesirable factors can lead to death; the type, duration, and goals of the procedure should be also taken into account.
We have aimed to find out what has changed in anesthesia of laboratory animals lately, which drugs are currently relevant and what is the reason for their popularity.
Anesthesia of mice is challenging for several reasons: animal size, metabolic rate, and high risk of hypothermia and hypoglycemia. In addition, anesthetics affect physiological parameters and therefore even more affect the results of experiments. At the moment, there is a large list of drugs used in laboratory animals. Since they are divided into groups depending on the routes of administration, we selected the following drugs from a number of articles: injectable anesthetics (medetomidine, dexmedetomidine, zoletil‑100, ketamine, xyla, propofol) and inhalation anesthetics (isoflurane, sevoflurane). Advantages and disadvantages of the drugs and their combinations were studied and described.
An analysis of the literature showed that injection anesthesia is considered the main method of anesthesia for experimental animals and is relatively well tolerated by animals; it also does not require additional bulky equipment and additional staff qualifications, there are antagonists for a number of drugs, and is also affordable.
In the majority of studies inhalation anesthesia was used in long-term complex manipulations/operations, since it is more manageable, agents require minimal metabolism, and in some cases do not require additional sedation.