Project 462812

Endometrial cancer (EC) is the most common gynecologic malignancy and the fourth most-commonly diagnosed cancer in Canadian women. The incidence of EC is rising worldwide. Based on 2021 Canadian Cancer Statistics, about 8000 women were diagnosed with EC and 1400 women died from the disease. Most women diagnosed with EC are managed with surgical resection of the uterus (hysterectomy) and are cured by this procedure; however, some remain at high-risk of cancer recurrence or spread. Despite adjuvant therapies, not all women are cured and better treatments are needed. Immune checkpoint inhibition treatment has transformed the treatment of multiple cancers, such as melanoma and lung cancer. Among patients treated with this type of immunotherapy, there is a relatively rare but important subgroup of cancers identified by specific features to the tumour called mismatch repair deficiency (MMRd) that respond well. Roughly one-third of all ECs are MMRd. Immunotherapy has proven to be effective for MMRd EC which has spread beyond the uterus and has not responded to chemotherapy. However, no study has evaluated if immunotherapy PREVENTS tumour recurrence or spread in early-stage MMRd EC. The purpose of this trial is to see if an immunotherapy drug, durvalumab, prevents recurrence or spread when given during and after post-surgery radiotherapy. The trial will provide important information on how the drug affects overall survival, side effects, and quality of life. Tumour tissue will be collected on all trial participants and analysis will help us better understand which tumours are at risk to recur and which will respond to durvalumab. The trial is led by the Dutch Gynecologic Oncology Group and will be conducted in Canada by the Canadian Cancer Trials Group. A total of 75 patients from 17 Canadian centres will be enrolled.