How would you sequence chemotherapy and radiotherapy for a patient with stage IIIC1 serous endometrial carcinoma?

Update to Recommendation (3/2025):
Clinical trial data supports incorporating immunotherapy with chemotherapy in the adjuvant setting for this group of patients. My recommendation for a patient with Stage IIIC1 serous endometrial cancer depends on the HER2 status as follows:

Adjuvant chemotherapy in advanced uterine serous carcinoma has been shown to improve survival. Radiation can be added for local control but my priority here would be the chemotherapy.

HER2 is important to check (as you have) as the addition of trastuzumab (for her2 + tumors) in the upfront setting h...