Type I endometrial ca is typically related to unopposed estrogen, either endogenous (obesity or ovarian pathology) or exogenous (unbalanced estrogen supplementation). Women with type I endometrial cancers typically have clinical risk factors including obesity, nulliparity, and late onset menopause. These tumours are typically diagnosed at an early stage because most women experience abnormal vaginal bleeding that is amenable to definitive investigation early during the course of the disease (office endometrial biopsy). Type I endometrial cancers are usually characterized by histology consistent with endometrioid adenocarcinoma that are often well-differentiated and only superficially invasive tumors at diagnosis. The prognosis for women with these tumours is typically excellent since they are often cured with definitive surgery alone.