Immunotherapy in Endometrial Cancer: Molecular Classification, Clinical Evidence, and Therapeutic Implications: A...

Endometrial cancer (EC) is the most common gynecologic malignancy in developed countries, with increasing incidence and limited options in advanced disease. Molecular classification has redefined risk stratification and therapeutic decision-making, particularly with the incorporation of immunotherapy. This review provides a clinically oriented overview of immunotherapy in EC across molecular subgroups and treatment settings.

A narrative review was conducted using PubMed/MEDLINE, Embase, and Web of Science, focusing on clinical trials and studies with direct clinical relevance.

Immune checkpoint inhibitors targeting the PD-1/PD-L1 axis have demonstrated significant benefit in EC, particularly in mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) tumors, where durable responses are observed. In contrast, mismatch repair-proficient (pMMR) tumors show limited sensitivity to monotherapy and require combination approaches. Recent phase III trials have established chemoimmunotherapy as a first-line standard, with greater benefit in dMMR tumors and clinically meaningful improvements in pMMR disease. In the second-line setting, PD-1 inhibitor monotherapy is standard for dMMR tumors, while lenvatinib plus pembrolizumab is a key option for pMMR disease. However, responses remain heterogeneous and are not fully explained by MMR status alone.

Immunotherapy is a cornerstone in advanced EC management, guided by molecular classification. Key challenges include limited efficacy in pMMR tumors, lack of robust predictive biomarkers, and uncertainty in treatment sequencing. Future strategies should focus on biomarker-driven approaches and rational combinations.