What is the most reliable diagnostic evaluation for postmenopausal bleeding suspected to be due to endometrial cancer?

The most reliable diagnostic evaluation for postmenopausal bleeding suspected to be associated with endometrial cancer is an endometrial biopsy. This procedure involves taking a sample of the endometrial tissue, which can then be assessed histologically for the presence of cancerous cells. Because postmenopausal bleeding often raises concerns about malignancy, particularly endometrial cancer, an endometrial biopsy allows for direct examination of the endometrium, making it the gold standard in diagnosing the condition.

Other diagnostic measures, such as a Pap smear, are not specifically designed to evaluate the endometrial lining and are primarily used for cervical cancer screening. Serum prolactin levels and serum FSH and LH levels do not provide relevant information regarding the presence of endometrial cancer and are not considered reliable tests for this specific concern. Therefore, the endometrial biopsy stands out as the most definitive method to confirm or rule out endometrial cancer in patients experiencing postmenopausal bleeding.