How likely is it for endometrial cancer to metastasize?

It depends: The answer to this really depends on the stage, grade and histology of the endometrial cancer. For example, early stage, low grade adenocarcinomas have a low chance to metastasize whereas a higher stage, papillary serous type endometrial cancer has a higher risk of metastasizing.

Uterine CA Spread: Patients with grade 1 tumors ) have a low risk (<5%) of nodal involvement. Patients with grade 2 or 3 tumors have a 5% to 9% incidence of pelvic node involvement and a 4% incidence of positive para-aortic nodes. Patients with deep muscle invasion and high-grade tumors and/or intraperitoneal disease have a significant risk of nodal spread, 20% to 60% to pelvic nodes and 10% to 30% to aortic nodes.

Endometrial cancer: It depends on the type of endometrial cancer, the grade of endometrial cancer and the thoroughness of the initial surgery. While the most common type spreads only about 15% of the time other more aggressive types spread more often (40-50%).