Which test is used to establish a histologic diagnosis of endometrial cancer?

• A. CA-125
• B. Transvaginal ultrasound
• C. Endometrial biopsy
• D. Pelvic exam

Answer: (C)

To confirm endometrial cancer, you need tissue viewed under a microscope—a histologic diagnosis. Obtaining an endometrial biopsy collects endometrial tissue that a pathologist can evaluate for malignant cells and other features. This tissue sampling is the gold standard for diagnosis.

Other tests play important roles but don’t provide histology. CA-125 is a blood marker that can be elevated in various conditions and is not specific or definitive for endometrial cancer. Transvaginal ultrasound can show endometrial thickening or masses and help assess risk, but it cannot prove cancer. A pelvic exam is a physical examination and cannot yield tissue for microscopic analysis.

Thus, endometrial biopsy is the best choice to establish the histologic diagnosis.