What adjuvant treatment would you recommend for a patient with FIGO 2023 IIIB2 endometrioid endometrial adenocarcinoma (Grade 3, p53mut, MMR proficient), metastatic to the uterine serosa, bilateral ovaries, and anterior peritoneal reflection?

Chemotherapy followed by pelvic RT

I don't routinely radiate these patients unless they are copy-number low/NSMP subset, in which case I give chemotherapy first and radiation.

These are the subset of patients in PORTEC-3 that benefitted from chemotherapy and based on GOG-0258, you can absolutely omit radiation. If this patient was staged and debulked to R0, then I would proceed with chemo alone. If they had measurable disease or stage IIIc2, I would add IO based on the RUBY sub-analysis that showed OS benefit in TP53 mutant tumors (to be clear this was an exploratory analysis).

There is also data to show that these patients benefit from the addition of bev based on sub-analysis from MITO-END2 and translational work on GOG86-P in p53 mutant tumors. This will be studied coming ...

For this patient, I would just give cuff brachy between cycles 1-2 if adequately healed, as with peritoneal and ovarian disease patterns of failure don't support EBRT in my eyes.