Colon cancer is the 3^rd most common malignant neoplasm and the 4^th leading cause of mortality from them. The majority of patients are diagnosed at stages II–IV, which indicates the need for markers that can predict disease progression, especially after surgical treatment. Recently, there has been a growing interest in exploring circulating tumor DNA as a marker of residual tumor in colon cancer. In 2018, the N.N. Blokhin National Medical Research Center of Oncology together with the Institute of Chemical Biology and Fundamental Medicine under the coordination of the Center for Strategic Planning and Management of Biomedical Health Risks initiated a research project entitled “Development of an assay for the diagnosis of various malignant tumors and treatment efficacy monitoring based on the analysis of circulating tumor DNA from patient blood”. This article provides a theoretical background for the project and a report on its progress made so far.

Objective: to analyze the spectrum of toxic reactions associated with various polyradiomodification regimens used in the combination therapy for rectal cancer.

Materials and methods. We have conducted a retrospective analysis of the data from a prospectively collected database. We included patients with stages сT2–3N0M0 and сT2–3N1–2M0 resectable rectal cancer. Polyradiomodification regimens included a course of radiotherapy (5 × 5 Gy) with the following radiomodifiers: rectal administration of a biopolymer composition containing metronidazole (MZ)  at a dose of 10 g/m² (twice), intracavitary local microwave hyperthermia (three times on days 3–5) and oral capecitabine (Cap).

Results. The study included 241 participants. Toxic reactions were observed in less than 33.2 % of patients receiving polyradiomodification as a part of combination therapy. The most common adverse events were gastrointestinal toxicity and neurotoxicity, diagnosed in 28.6 % and 17.4 % of cases respectively. The frequency of toxic reactions was significantly higher in patients receiving Cap14 + MZ regimen than in those receiving Cap5 + MZ regimen (p = 0.0038). However, the inclusion of microwave hyperthermia in both Cap5 and Cap14 therapeutic regimens had no impact on the frequency of toxic reactions (44.2 and 31.5 % respectively, p = 0.146). The proportion of patients with grade III gastrointestinal toxicity did not significantly vary across the groups (p = 0.16).

Conclusion. The course of polyradiomodification included into the combination therapy for rectal cancer has an acceptable toxicity profile and can be used to improve long-term outcomes of combination treatment for rectal cancer.

Background. The evaluation of clinical and morphological characteristics is not sufficient to predict the prognosis of metastatic colorectal cancer (mRCC). Tumor aggressiveness may vary significantly even in patients with similar clinical and morphological disease characteristics. These differences are believed to be associated with molecular tumor characteristics and can be used as additional prognostic factors for patient survival.

Objective: to evaluate the effect of topoisomerase IIα overexpression (topoIIα) in primary colon tumor on the mRCC prognosis.

Materials and methods. The study cohort included patients with mRCC that have not previously received treatment for disseminated disease. All participants had a morphologically verified diagnosis of colon adenocarcinoma and received first-line chemotherapy with oxaliplatin and capecitabine. We evaluated both short-term and long-term treatment outcomes. We also assessed the expression of topoIIα in primary colon tumors (biopsy/surgical specimens obtained prior to initiation of first-line treatment) using immunohistochemical methods. We aimed to evaluate the association between the level of topoIIα expression and short-term/long-term treatment outcomes. We analyzed the impact of topoIIα expression in the primary tumor on the efficacy of first-line chemotherapy, progression-free survival (PFS) and overall survival (OS) in patients with mRCC.

Results. Immunohistochemical evaluation of topoIIα expression in the primary tumor was conducted for 39 patients with mRCC. We found no correlation between topoIIα expression and PFS, i.e. median PFS did not differ significantly between patients with topoIIα-positive and topoIIα-negative tumors (p >0.05). Individuals with low levels of topoIIα expression in the primary tumor and those with topoIIα-negative cancer demonstrated significantly higher OS than patients with topoIIα overexpression (median OS 16.30 ± 2.0 months; 95 % confidence interval 12.32–20.28 vs 7.7 ± 4.98 months; 95 % confidence interval 0.00–17.46; p = 0.007).

Conclusion. Overexpression of topoIIα is a factor of poor prognosis associated with poorer OS in patients with mRCC that received first-line chemotherapy with oxaliplatin and capecitabine.

Objective: to analyze treatment outcomes in patients with locally advanced rectal cancer that received various combinations of neoadjuvant chemotherapy and chemoradiotherapy.

Materials and methods. In this retrospective study, we analyzed a cohort of prospectively recruited patients with stage mrT3(CRM+)/ T4N0–2M0 locally advanced rectal cancer. Participants were divided into three groups. Patients in Group 1 received preoperative longcourse radiotherapy given concurrently with capecitabine, followed by 2–6 cycles of consolidation chemotherapy with capecitabine and oxaliplatin (CapOx). In Group 2, patients initially received 1–2 cycles of induction chemotherapy with CapOx, followed by radiotherapy + capecitabine, and then consolidation chemotherapy with CapOx (“sandwich” method). Participants in Group 3 were treated with 1–3 cycles of induction CapOx chemotherapy with subsequent long-course chemoradiotherapy. After the combination treatment, all patients underwent surgery. The primary endpoint of this study was therapeutic pathomorphosis. Secondary endpoints included complete clinical response, toxicity, local recurrence, distant metastasis, and relapse-free survival.

Results. This study included 155 patients (98 in Group 1, 44 in Group 2, and 13 in Group 3). Grade III toxicity was documented in 6.12 %, 4.55 %, and 23.08 % of cases in Groups 1, 2, and 3 respectively. None of the patients had grade IV toxicity. Grade III therapeutic pathomorphosis was achieved in 33.7 %, 22.7 %, and 23.1 % of patients in Groups 1, 2, and 3 respectively. Grade IV therapeutic pathomorphosis was observed in 14.3 %, 15.9 %, and 7.69 % of patients in Groups 1, 2, and 3 respectively. Complete clinical response was registered in 16.3 %, 11.4 %, and 0 % of cases in Groups 1, 2, and 3 respectively. Median follow-up was 47.2 months with no signs of progression. Relapses were observed in 1.02 % and 2.27 % of patients from Group 1 and Group 2 respectively, whereas Group 3 demonstrated no relapses. A total of 11.22 %, 13.64 %, and 23.1 % of participants from Groups 1, 2, and 3 respectively developed distant metastasis.

Conclusion. Polychemotherapy used within the consolidation and «sandwich» treatment regimens is a promising option for the treatment of locally advanced rectal cancer. The efficacy of induction chemotherapy should be further studied with a larger sample.

Presacral venous bleeding is a rare but potentially fatal complication in pelvic surgery. This type of bleeding is difficult to control. Existing methods are not without shortcomings, therefore, the search for a more reliable method. We are present a case of successful bleeding control using by plates of medium-porous nitinol (pore size of 300–450 μm, permeability of 12 × 10–9). Hemostasis was carried out by pressing  a plate to the bleeding zone for 4 minutes.

We report a case of successful treatment of a 15-year-old female patient (body mass index 16) diagnosed with Turcot syndrome (familial adenomatous polyposis of the colon) combined with multiple primary malignant tumors, including anaplastic astrocytoma (received combination therapy in 2007), metachronous cecal cancer (underwent subtotal colectomy and 12 courses of polychemotherapy in 2016–2017), and metachronous stage III pT3N1M0 rectal cancer at 8 cm. The patient underwent laparoscopic low resection with extirpation of the ileosigmoid anastomosis, creation of a reservoir-rectal anastomosis, and preventive ileostomy. The patient had minimal intraoperative blood loss and uneventful postoperative period (with an accelerated rehabilitation protocol). She was discharged from a hospital on day 9. Considering previous treatment episodes and the disease stage, we also included into the treatment regimen adjuvant FOLFOX polychemotherapy in a reduced dose for 6 months. During one-year follow up, there was no evidence of disease progression. Later, the patient underwent ileostomy closure with forming a side-to-side mechanical anastomosis. The patient is fully rehabilitated in term of her social activity.