Background. The approach to the management of prostate cancer with lymph node metastases has recently moved towards aggressive multi-modal treatment with the use of the most rational combinations that are currently available. Objective: to assess the efficacy and tolerability of chemohormonal therapy (CHT) in patients with high-risk and very high-risk prostate cancer. Materials and methods. An open prospective clinical trial evaluating the efficacy and tolerability of neoadjuvant and adjuvant CHT in patients with high-risk and very high-risk prostate cancer was initiated in 2016 at the P.A. Herzen Moscow Oncology Research Institute. Patient recruitment is still ongoing. A total of 64 patients with high-risk and very high-risk prostate cancer (сT3N0-T3N+М0, prostate specific antigen (PSA) ≥20 ng/mL, and Gleason score of 8-10) were recruited since July 2016. All patients were examined prior to treatment initiation and after 3 and 6 courses of therapy. The examination included pelvic magnetic resonance imaging, ultrasound imaging of the abdominal cavity and retroperitoneal space, transrectal ultrasound imaging, and chest radiography or computed tomography. Serum PSA level was evaluated before each course of therapy. Bone scintigraphy was performed before treatment and after its completion. Study participants were divided into two groups. Group A included patients that initially underwent surgical treatment and then 6 courses of CHT no later than 6 weeks after surgery: docetaxel 75 mg/m2 given intravenously on day 1 of a 21-day cycle and oral prednisolone 10 mg/day. Patients also received hormonal therapy with luteinizing hormone-releasing hormone analogue (aLHRH) given in depot injections every 28 days. Group B included patients that initially received 6 courses of CHT: docetaxel 75 mg/m2 given intravenously on day 1 of a 21-day cycle and oral prednisolone 10 mg/day. After that, patients underwent radical prostatectomy with pelvic lymphadenectomy no later than 4 weeks after the completion of chemotherapy. Patients also received hormonal therapy with aLHRH given in depot injections every 28 days. The total treatment duration was 6 months. Results. The group of adjuvant CHT included 24 patients with high-risk prostate cancer (T3b-4N+М0 with at least 5 regional lymph node metastases detected by morphological examination of surgical specimens). All patients had Gleason score 8-10 tumors. Mean age of patients was 63.0 ± 7.7 years (range: 46-72 years). In total, all patients received 142 courses of CHT. By the time of publishing this article, 23 (96 %) of patients completed their treatment. The group of neoadjuvant CHT included 40 patients with very high-risk prostate cancer (T3b-4N+М0 with metastases to pelvic and retroperitoneal lymph nodes detected by instrumental examination). All patients had Gleason score 8-10 tumors. Mean age of patients was 61.0 ± 6.4 years (range: 43-69 years). In total, all patients received 236 courses of CHT. By the time of publishing this article, 36 (90 %) of patients completed their treatment. Thirty-five patients (87 %) underwent radical prostatectomy with extensive pelvic and paraaortic lymphadenectomy. Routine pathological examination demonstrated that all patients had signs of tumor destruction. Thirty-three participants (94 %) had grade II therapeutic pathomorphosis, whereas 2 patients (6 %) had grade III therapeutic pathomorphosis. Median PSA relapse-free survival (PSA-RFS) rate in the neoadjuvant CHT group was 10 months. Serum PSA of 0.1 ng/mL 1 month postop-eratively correlated with longer RFS (р = 0.04). Biochemical relapse (PSA level >0.2 ng/mL) was observed in 6 patients (15 %) from this group. Later these patients received hormonal therapy with aLHRH. Median PSA-RFS in the adjuvant CHT group was 11 months. The main adverse events in the two groups were hematological toxicity, observed in 24 patients (34.29 %), and gastrointestinal toxicity, observed in 9 patients (12.86 %) (diarrhea (n = 6) and stomatitis (n = 3)). Only grade I-II toxicity was registered so far. Two patients (3.1 %) had febrile neutropenia, which required cytostatic dose reduction by 20 %. Relatively good tolerability and acceptable quality of life allowed the vast majority of patients to be treated on an outpatient basis. Conclusion. So far, we can make only a preliminary conclusion that adjuvant and neoadjuvant CHT is a promising treatment strategy for high-risk and very high-risk prostate cancer. © ABC-press Publishing House. All rights reserved.