Endometrial cancer originates in the endometrium, the inner lining of the uterus. Early detection improves treatment outcomes. When symptoms like abnormal uterine bleeding occur, especially after menopause, ultrasound is often an initial imaging tool.
Understanding Endometrial Ultrasound
Ultrasound is a medical imaging technique that uses high-frequency sound waves to generate real-time images of internal body structures. These sound waves bounce off tissues, and a computer translates the echoes into visual representations. Two primary types of ultrasound are commonly used to evaluate the uterus.
Transabdominal ultrasound involves placing a transducer on the lower abdomen, providing a general overview. Transvaginal ultrasound (TVUS) offers a more detailed view of the uterus and its endometrial lining. A slender probe is inserted into the vagina, positioning it closer to the uterus for higher resolution images. This makes TVUS the preferred method for assessing endometrial thickness and structure.
Ultrasound Findings Related to Endometrial Cancer
Ultrasound can reveal characteristics that may suggest endometrial cancer. A significant indicator is increased endometrial thickness, particularly in postmenopausal women. While normal endometrial thickness in postmenopausal women not on hormone therapy is typically 4 millimeters or less, a greater thickness often warrants further investigation.
Other suspicious findings include an irregular or heterogeneous endometrial echo pattern, meaning the lining appears uneven. The presence of fluid within the uterine cavity, such as hematometra (blood) or pyometra (pus), can also be a concerning sign. These fluid collections might occur if a mass obstructs the cervical canal. These ultrasound findings are suspicious and indicate a need for further evaluation.
Limitations of Ultrasound for Diagnosis
Ultrasound cannot definitively diagnose endometrial cancer. The images produced by ultrasound reflect structural changes but do not provide information about the cellular composition. This means ultrasound cannot distinguish between benign conditions, such as endometrial polyps, submucosal fibroids, or endometrial hyperplasia, and malignant changes.
Furthermore, ultrasound is unable to determine the specific type or stage of endometrial cancer. It provides a visual representation, but a cellular diagnosis is required to confirm malignancy. Factors like obesity or the presence of gas in the bowel can sometimes obscure the view and limit the clarity of ultrasound images. Therefore, a suspicious finding on ultrasound always necessitates additional diagnostic procedures to ascertain the nature of the endometrial changes.
Subsequent Diagnostic Procedures
When an ultrasound reveals suspicious findings regarding the endometrial lining, subsequent diagnostic procedures are typically recommended to obtain a definitive diagnosis. The most conclusive method for confirming or ruling out endometrial cancer involves obtaining tissue samples for microscopic examination. This can be achieved through an endometrial biopsy, where a thin, flexible tube is inserted into the uterus to collect a small tissue specimen.
Another procedure is a dilation and curettage (D&C), often performed with hysteroscopy. During a hysteroscopy, a thin, lighted telescope is inserted into the uterus, allowing the doctor to visually inspect the endometrial cavity and directly target areas for biopsy. These tissue samples are then sent to a pathologist, who examines them under a microscope to identify cancerous cells. If cancer is confirmed, further imaging tests like MRI or CT scans may be performed to determine the extent of the disease for staging.