What Is Uterine Sarcoma?

Cancer cases that affect  the female reproductive system are on the rise, with uterine cancer now ranking as the 8th most common type of cancer in the UK. Uterine sarcoma, a rare type of cancer occurring in the muscle cells and other soft tissues of the uterus (womb) constitutes about 1% of uterine cancers in the UK.¹  

Read on to find out more about uterine sarcomas, how it is caused, various accompanying symptoms, and how  it is currently managed and treated. 

Overview

The female reproductive system is made up of internal (vagina, uterus, fallopian tubes, and ovaries) and external parts (vulva, clitoris and urethra), which work together to support hormone balance, childbearing and birth. The uterus is a pear-shaped organ located in the lower abdomen made up of the endometrium (the innermost layer), myometrium (the middle layer made of smooth muscle) and perimetrium (the outermost layer made of connective tissue). Uterine sarcoma is a rare type of cancer that begins in the myometrium or other supporting tissues of the uterus and accounts for 3-7% of all uterine cancers.¹

Uterine sarcomas are referred to as soft tissue sarcomas and can occur at any age in people assigned female at birth (AFAB), but are more prevalent after menopause (aged 75-79).¹ Depending on the anatomical region and the cell type the sarcoma develops from, they are classified into different categories.

Uterine sarcomas are classified into:^1,2

• Carcinosarcoma: This is an aggressive type of uterine sarcoma that has characteristics of both a carcinoma,a type of cancer that begins in the epithelium (the cells that line organs) and a sarcoma (a type of cancer that begins in soft tissues). They account for 50% of diagnosed cases and are now classified as carcinomas of the endometrium
• Leiomyosarcoma (LMS): This is the most common type of uterine sarcoma, accounting for about 30% of cases. It begins in the smooth muscle cells of the uterus and these tumours grow quickly, leading to the spread of cancer cells to other parts (metastasis)
• Endometrial stromal sarcoma (ESS): This type of uterine sarcoma begins in the connective tissue or stroma of the endometrium of the uterus accounting for 15% of uterine cancers
• Adenosarcoma: This is a rare type of uterine sarcoma that is made up of normal epithelial gland (female hormone-releasing) cells of the uterus and cancer cells. They account for 5-10% of uterine cancers and are slow growing,  making them easily treatable
• Undifferentiated sarcoma: This is a rare and aggressive type of uterine sarcoma that is made up of cancer cells. They account for 5% of uterine cancers and  have a poor prognosis due to their rapid growth. Undifferentiated sarcomas are typically seen in patients above the age of 60

Each type of uterine sarcoma has its unique characteristics and treatment options and depending on the diagnosis, laboratory and tumour staging your oncologist/ doctor will come up with the best course of personalised treatment.. 

In addition to it your doctor rates (staging) the diagnosis (I through IV) to indicate the extent of cancer spread . The more cancer has spread throughout your body, the higher the number. 

Causes of uterine sarcoma

Uterine sarcoma is rare compared to other uterine cancers, hence making it hard for researchers to find the exact cause. Researchers are still learning about the DNA alterations that occur when healthy uterine cells transform into sarcomas, which can help with finding effective treatment and early diagnosis strategies. But certain genetic and risk factors have been identified to be associated with the start of uterine sarcomas.

Factors associated with the cause of uterine sarcomas are:^1,2

• Age: Uterine sarcoma is more common in the postmenopausal age group, typically between the ages of 50 and 70. The risk of developing uterine sarcoma increases with age
• Radiation exposure: People AFAB who have received pelvic radiation therapy as part of cancer treatment have an increased risk of developing uterine sarcoma. This includes those who have had radiation therapy for cervical or ovarian cancer
• Hormonal factors: Exposure to oestrogen  without progesterone is a known risk factor for uterine sarcoma. INdividuals AFAB who have undergone hormone replacement therapy (HRT) or have a history of endometrial hyperplasia (a condition where the lining of the uterus becomes too thick) are at a higher risk of developing uterine sarcoma
• Genetic factors: While most cases of uterine sarcoma are sporadic (not caused by inherited genetic mutations), some people with specific genetic syndromes, such as Li-Fraumeni syndrome, may be at higher risk of developing uterine sarcoma. Certain studies showed women with the abnormal gene Rb1 which causes eye cancer, retinoblastoma were  at a higher risk of developing uterine sarcoma
• Tamoxifen: Tamoxifen is an anti-cancer drug used to treat breast cancer. People who take or have taken tamoxifen have a slightly increased risk of developing uterine sarcoma
• Exposure to diethylstilbestrol (DES): DES is a synthetic form of oestrogen that was prescribed to pregnant women in the mid-20th century to prevent miscarriages. Patients who were exposed to DES before birth or during their mother's pregnancy have an increased risk of developing uterine sarcoma

While these risk factors may increase a person's likelihood of developing uterine sarcoma, most women with these risk factors do not develop the disease. Additionally, many people AFAB who develop uterine sarcoma have no known risk factors.

Signs and symptoms of uterine sarcoma

The primary signs and symptoms of uterine sarcoma are comparable to those of endometrial cancer and benign (non-cancerous) growths like fibroids. Before the uterine sarcoma has advanced, you might not experience any symptoms . But it is very likely to experience symptoms once the severity of the cancer increases. 

Signs and symptoms of uterine sarcoma may include:

• Abnormal vaginal bleeding: This is the most common symptom of uterine sarcoma. It may include heavy periods, bleeding between periods, bleeding after menopause, or any other type of abnormal bleeding
• Bleeding accompanied with foul smelling discharge
• Pelvic pain or pressure: Some people with uterine sarcoma may experience pain or pressure in the pelvic area
• A lump/mass near the vaginal area
• Abdominal swelling: In some cases, uterine sarcoma can cause the uterus to enlarge, leading to abdominal swelling
• Increased/frequent urination
• Constipation
• Anaemia: Heavy or prolonged bleeding can lead to anaemia, which may cause fatigue, weakness, and shortness of breath
• Pain during intercourse: Some patients with uterine sarcoma may experience pain or discomfort during sexual intercourse

It's important to note that these symptoms are not specific to uterine sarcoma and can be caused by other conditions as well. However, if you experience any of these symptoms, it's important to speak with your GP for an accurate diagnosis.

Management and treatment for uterine sarcoma

The management and treatment of uterine sarcoma depend on several factors, including the type and stage of cancer, as well as the patient's overall health and preferences. 

Uterine sarcoma treatment options may include:

• Surgery: The main treatment for uterine sarcoma is surgery to remove the uterus (hysterectomy) and sometimes other nearby organs such as the ovaries and fallopian tubes. The type of surgery may depend on the stage and location of the tumour
• Radiation therapy: High-energy X-rays or other forms of radiation are used in radiation treatment to kill cancer cells. It may be used before or after surgery, depending on the stage of the cancer
• Chemotherapy: Chemotherapy uses drugs to kill cancer cells. It may be given before surgery to shrink the tumours or eradicate remaining cancer cells after surgery, or in cases where surgery is not possible
• Hormone therapy: Hormone therapy uses drugs to block the effects of oestrogen  or progesterone, which can stimulate the growth of some types of uterine sarcoma
• Targeted therapy: Targeted therapy (eg. immunotherapy) is a type of treatment that targets specific proteins in cancer cells. It may be used in some cases of uterine sarcoma, but it is not yet widely used

The treatment plan for each person will be personalised based on their individual needs and circumstances. It's important to discuss treatment options and its possible side effects with your oncologist to make an informed decision.

FAQs

How is uterine sarcoma diagnosed?

Uterine sarcoma is diagnosed through transvaginal ultrasound and through a biopsy, which involves removing a small sample of tissue for examination if cancer cells are present. Additional imaging tests such as ultrasound, MRI, or CT scans are done to confirm the diagnosis and see the progression of uterine sarcoma.

How can I prevent uterine sarcoma?

There is no known way to prevent uterine sarcoma, but regular gynaecological exams and preventive genetic testing can help detect it early.

What are the stages of uterine sarcoma?

The stages of uterine sarcoma are based on the size and location of the tumour, as well as whether it has spread to other parts of the body. There are four stages, ranging from stage I (localised to the uterus) to stage IV (spread to distant organs).

Who is at risk of uterine sarcoma?

Risk factors for uterine sarcoma include older age, previous radiation therapy, and certain genetic conditions. People AFAB who have had tamoxifen therapy for breast cancer may also be at higher risk.

How common is uterine sarcoma?

Uterine sarcoma is very rare, accounting for only about 1% of all uterine cancers.

When should I see a doctor?

If you experience symptoms like abnormal vaginal bleeding, pelvic pain, or a mass or lump in the pelvis region, you should see a doctor right away. Early detection and treatment can improve the chances of successful recovery.

Summary

Uterine sarcoma is a rare and aggressive type of cancer that develops in the muscles or tissues of the uterus. It is more commonly diagnosed post menopause, in those who have had previous radiation therapy to the pelvic area or have had chemotherapy to treat breast cancer. The symptoms of uterine sarcoma are similar to those of other uterine conditions, such as fibroids and endometriosis, and may include abnormal vaginal bleeding. Treatment options for uterine sarcoma depend on the stage and type of cancer. Surgery, radiation therapy, and chemotherapy may be used alone or in combination to treat cancer.

Persons diagnosed with this condition should receive regular gynaecological exams and report any abnormal symptoms to their doctor, especially if they have a history of uterine conditions, radiation therapy, or exposure to chemotherapeutic drugs.

While uterine sarcoma is a rare condition, people AFAB need to be aware of the symptoms and risk factors and seek medical attention if they experience any abnormal symptoms related to their reproductive system.