A 63 year-old G0P0 woman presents for her first pelvic exam since becoming menopausal at age 55. On reviewing her history, you discover that she has been experiencing occasional vaginal bleeding for...

A 63 year-old G0P0 woman presents for her first pelvic exam since becoming menopausal at age 55. On reviewing her history, you discover that she has been experiencing occasional vaginal bleeding for almost a year. On physical exam, she has a slightly enlarged uterus but no adnexal masses, although exam is limited by her obesity. You perform an endometrial biopsy, which returns grade 3 adenocarcinoma. The patient undergoes TAH-BSO and surgical staging, revealing stage IIIC endometrial cancer, for which she receives postoperative radiation treatment. Which of the following is not a risk factor for endometrial cancer?

A. Obesity

B. Nulliparity

C. Chronic anovulation

D. Early age of first intercourse

E. Late menopause