Immunotargeting therapy of MSS/pMMR — advanced endometrial cancer. Literature review and presentation of clinical practice

Drug therapy for advanced endometrial cancer (EC) has remained a challenging task for practical oncology for many years. Despite the effectiveness of standard platinum chemotherapy, most patients develop resistance to the treatment and further disease progression. Chemotherapy drugs used in the 2 nd line of therapy show unsatisfactory results in terms of effectiveness. The situation has radically changed after the discovery of the role of microsatellite instability as a predictive marker of the effectiveness of immunotherapy. EC is the leading nosology in terms of the frequency of deficient mismatch repair system (dMMR) and demonstrates a high incidence of tumors with the phenomenon of high microsatellite instability (MSI-H). For such patients, the standard of treatment has become the use of immunotherapy, in monotherapy and in combination with platinum drugs. However, 70% of patients with EC show no signs of microsatellite instability in tumor tissue (MSS/pMMR), and for many years the introduction of immunotherapy into this subgroup has been associated with very low results, not exceeding the effectiveness of standard chemotherapy regimens. Only the use of a combined approach, a combination of immunotherapy and targeted therapy demonstrated an improvement in long-term treatment outcomes, disease-free survival (DFS) and overall survival (OS) in the MSS/pMMR group of endometrial cancer. In this article, we present the literature review on the effectiveness of this regimen, demonstrate the practical experience of St. Petersburg GBUZ «City Clinical Oncology Dispensary» in using a combined regimen, and also illustrate statistical data with a real clinical case effectiveness of this treatment tactic.