Uterine cancer, also known as endometrial cancer, originates in the lining of the uterus, called the endometrium. It is a common gynecological cancer, with increasing incidence in high-income countries. Early detection significantly improves treatment outcomes, making various diagnostic tools important in identifying potential issues. Imaging techniques, such as ultrasound, play a role in the initial assessment of symptoms that could suggest uterine abnormalities.
What an Ultrasound Reveals
An ultrasound uses sound waves to create images of internal organs, revealing information about the uterus. A primary finding is the thickness of the endometrial lining. For postmenopausal women, an endometrial thickness greater than 4-5 mm suggests a potential problem and warrants further investigation. A normal endometrial thickness for postmenopausal women not on hormone replacement therapy is 5 mm or less.
For premenopausal women, endometrial thickness varies throughout the menstrual cycle. During menstruation, it ranges from 2-4 mm, increasing to 5-7 mm in the early proliferative phase and up to 11 mm in the late proliferative or preovulatory phase. In the secretory phase, it can range from 7-16 mm. Abnormal thickness for a premenopausal woman’s cycle is a concerning indicator.
Beyond thickness, ultrasound can identify other suspicious features within the uterine cavity. This includes masses, polyps, or other growths, which may appear as areas with irregular contours. Fluid collection within the uterus can also be observed. These findings require additional evaluation and do not provide a definitive cancer diagnosis.
Understanding Ultrasound’s Role in Diagnosis
Ultrasound serves as an initial screening tool for uterine issues, but it cannot definitively diagnose uterine cancer. It provides images of the uterus’s structure, detecting abnormalities like thickened endometrial walls or masses. Ultrasound visualizes physical structures and fluid, but cannot analyze the cellular composition of tissues.
Ultrasound cannot differentiate between benign (non-cancerous) and malignant (cancerous) growths. For instance, it can show a thickened endometrium but not confirm if it’s due to benign hyperplasia or cancerous cells. While ultrasound results guide further steps, they do not provide a final confirmation of cancer. A definitive diagnosis requires microscopic examination of tissue, as only cellular analysis confirms cancer.
Further Diagnostic Procedures
If an ultrasound reveals suspicious findings, such as an abnormally thickened endometrium or growths, subsequent procedures obtain a definitive diagnosis. These methods involve obtaining tissue samples for examination.
An endometrial biopsy is a common test, often performed in a doctor’s office. A thin, flexible tube is inserted through the cervix into the uterus, and a small sample of the endometrial lining is removed. This procedure takes less than 15 minutes and may cause mild cramping. The tissue sample is sent to a lab for microscopic analysis to check for abnormal or cancerous cells.
Hysteroscopy with biopsy offers a direct approach. During hysteroscopy, a hysteroscope, a tiny telescope-like instrument with a camera and light, is inserted through the cervix into the uterus. Clear fluid is passed through the hysteroscope to expand the uterine cavity, allowing a clearer view of the lining on a screen. This direct visualization enables the doctor to identify suspicious areas and take targeted tissue samples for biopsy, which is considered more accurate than blind sampling. This procedure can be done in an office setting, sometimes with local anesthesia.
Dilation and Curettage (D&C) obtains a larger tissue sample from the uterine lining, often performed if an endometrial biopsy is inconclusive or provides insufficient tissue. This minor surgical procedure involves dilating the cervix to access the uterus. A surgical instrument called a curette scrapes tissue from inside the uterus. A D&C can be performed with or without hysteroscopy and may require anesthesia.
Once cancer is confirmed, MRI or CT scans are used for staging. These scans help determine the extent of the cancer, including its size, depth of invasion into the uterine wall, and whether it has spread to lymph nodes or other parts of the body. MRI is often preferred for evaluating the local extent of the disease, while CT scans can detect distant metastases. These imaging studies are crucial for guiding the appropriate treatment plan after a definitive diagnosis has been established through tissue analysis.