“Ask Dr HKSH” - Endometrial Cancer

Dr. NGAN Yuen Sheung, Hextan

Specialist in Obstetrics and Gynaecology

Q1. Endometrial cancer is a type of uterine cancer. How common is it?

Uterine cancer includes cancers of both the uterine body and the cervix, which are two different parts. Cancer of the uterine body can be further divided into two types: endometrial cancer and sarcoma. Endometrial cancer is the most common type, while sarcoma, which grows in the muscle stroma of the uterus, is relatively rare, accounting for only about three to six percent of uterine cancers. Endometrial cancer is more common.

Historically, cervical cancer was more common than endometrial cancer, but currently endometrial cancer has become more prevalent. In 2021 Hong Kong data, among common gynaecological cancers, endometrial cancer ranked fourth and cervical cancer ranked seventh.

Q2. What are the symptoms of endometrial cancer?

The most common symptom of endometrial cancer is postmenopausal bleeding. The median age of onset for endometrial cancer is approximately 57 years old, indicating that most patients have gone through menopause. Bleeding after menopause should always be evaluated by a doctor to rule out the possibility of endometrial cancer. Other less common symptoms include increased vaginal discharge and abdominal pain. In the later stages, additional symptoms may appear, affecting areas such as the lungs and bones.

Q3. Which women are at higher risk for endometrial cancer? 

Endometrial cancer is usually related to high estrogen levels. Some data indicate that women who begin menstruating early and go through menopause later, or who have polycystic ovary syndrome, tend to have higher estrogen levels. Women who have never given birth or are infertile are also at higher risk. Additionally, previous breast cancer patients who have taken tamoxifen hormones may face a higher likelihood of developing endometrial cancer. Lastly, a family history of endometrial or colon cancer can further increase risk. In such cases, doctors will test for hereditary genes linked to Lynch syndrome. If confirmed, her risk of developing endometrial cancer is also higher.

Q4. How is endometrial cancer diagnosed?

When a patient presents with postmenopausal bleeding, the doctor will first take a sample of the endometrium for testing. This can be accomplished through an endometrial aspiration procedure, which can be performed in a clinic without anaesthesia. If the aspiration results are inconclusive, further examination with hysteroscopy and curettage will be arranged to collect endometrial tissue and check for cancerous cells.

Another common examination method is an ultrasound, mainly to measure the thickness of the endometrium. If the endometrial thickness after menopause exceeds 4 millimetres, it should be monitored.

Patients often ask if a Pap smear can assist in diagnosing endometrial cancer. Such results are not reliable as the cells associated with endometrial cancer reside within the endometrium. The Pap smear primarily collects cervical cells, although abnormal endometrial cells may occasionally be identified, prompting further testing to detect and the discovery of endometrial cancer.

In early-stage endometrial cancer, the disease typically remains confined to the endometrium or the uterine body. This stage is considered stage I. Generally, the earlier the staging, the higher the chance of successful treatment. Therefore, patients should see a doctor promptly if they notice postmenopausal bleeding. If cancer cells are found solely in the endometrium, it is classified as stage I. If it has spread to the cervix, it is stage II. If it has extended to the vagina, lymph nodes, etc., it is classified as stage III. Stage IV refers to metastasis to the bladder, rectum, or more distant organs such as the lungs and bones. 

It is important to note that if detected in stage I, the chance of cure can be as high as 80-90%. Therefore, early detection is crucial for early and successful treatment.

Q5. What treatment options are available for endometrial cancer?

The primary treatment for endometrial cancer is surgery. The basic procedure involves the removal of the uterus, fallopian tubes, and ovaries.

In some cases, a staging surgery may also be required. Staging surgery does not refer to conducting the surgery in two separate procedures. Instead, if the doctor finds risk factors during the pre-operative assessment, additional surgical procedures may be necessary, such as removing pelvic or abdominal aortic lymph nodes to clarify the staging. Cancer cells may initially appear confined to the uterine body, suggesting stage I. However, if they have spread to the lymph nodes, it is classified as stage III. The purpose of staging surgery is to help doctors determine the actual stage of the cancer, as treatment protocols differ based on the stage.

For patients in stage I without high-risk factors, the treatment is completed once the uterus and bilateral fallopian tubes are removed. However, if the patient has other high-risk factors, post-operative radiotherapy may be necessary. This can be done as brachytherapy, which involves radiotherapy through the vagina, or whole pelvic radiation therapy. If the cancer cells have spread to the lymph nodes or other areas, chemotherapy or targeted therapy may also be necessary.

Q6. Will endometrial cancer recur after total removal of the uterus?

Actually, all cancers have the potential to recur. Cancer occurs as it has already invaded the base layers of original tissues, and possibly even the lymphatic and blood vessels. In the early stages, the number of cancer cells that have spread is relatively small, which reduces the chance of recurrence. In more advanced stages, there is typically visible spread, thus increasing the likelihood of recurrence. Women diagnosed with stage I endometrial cancer have a recurrence risk of less than 10%, but in later stages, the chance could be 20-30%.

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