Would you recommend adjuvant therapy for a non-invasive Grade 3 endometrioid endometrial cancer that is P53 wild-type and MMR deficient (due to methylation)?

I would not give adjuvant therapy.

The risk of nodal met is low based on GOG 33 and all other known data. Given that the tumor is p53 negative, I am going to assume it will not behave as a serous tumor.

So, would observe.