After joining the trial, you will be randomly assigned to receive either trastuzumab deruxtecan or standard chemotherapy treatment. This assignment is done by chance, similar to flipping a coin.

The treatment you receive will begin within 8 weeks after your endometrial cancer surgery.

Before starting treatment, your heart function will be checked to ensure your left ventricular ejection fraction (a measure of how well your heart pumps blood) is at least 50%. This test must be completed within 28 days before treatment begins.

Your physical condition will be assessed using a scale that measures your ability to perform daily activities. This assessment must be done no more than 14 days before treatment starts.

Blood tests will be performed within 14 days before treatment begins to check your organ function and bone marrow health. These tests may be repeated within 72 hours before your first treatment dose.

If you are assigned to receive trastuzumab deruxtecan (also called T-DXd or DS-8201a), this medication will be given through a vein as an intravenous infusion.

The medication is administered as a solution that is infused slowly into your vein over a period of time.

If you are assigned to receive standard chemotherapy, you will receive a combination of carboplatin and paclitaxel. Both medications are given through a vein as intravenous infusions.

Alternatively, you may receive a combination of cisplatin and docetaxel, also given as intravenous infusions or injections.

The specific combination will be determined based on what is considered standard care and your doctor’s judgment.

Some patients receiving standard chemotherapy may also receive radiotherapy (radiation treatment) as part of their treatment plan.

Throughout the treatment period, you will have regular check-ups and tests to monitor your health and any side effects.

These monitoring visits will include vital signs measurements, blood tests to check organ function, heart function tests using echocardiogram or MUGA scan (tests that create images of your heart), and electrocardiograms (tests that measure the electrical activity of your heart).

Eye examinations will also be performed to check for any vision-related side effects.

You will be asked to complete questionnaires about your quality of life and any symptoms you may be experiencing.

During and after treatment, imaging scans will be performed regularly to check whether the cancer has returned.

These scans will be reviewed both by your local medical team and by independent experts to assess whether there is any sign of cancer recurrence in the local area, nearby regions, or distant parts of the body.

If there is any suspicion of cancer returning, tissue samples may be taken to confirm the diagnosis.

After completing treatment, you will continue to be followed for an extended period.

The trial is expected to continue until February 2032, which means you may be monitored for several years to assess the long-term effectiveness of the treatment and your overall survival.

During this time, information will be collected about any cancer recurrence, your overall health status, and survival.