Uterine leiomyosarcoma is a rare and aggressive cancer that occurs in the uterus. Individuals usually require a hysterectomy. Treatments can also include chemotherapy or radiotherapy.

Leiomyosarcoma is a rare type of cancer that develops in the smooth muscle in body organs. The tumor can grow in the intestines, bladder, and other areas.

Females have a smooth muscle called the myometrium in the uterus. The myometrium generates contractions involved in menstruation and childbirth. Leiomyosarcoma can occur in the myometrium, and people refer to this as uterine leiomyosarcoma.

This article examines the symptoms, causes, and treatments for uterine leiomyosarcoma. It discusses how doctors diagnose the condition and answers some frequently asked questions.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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Symptoms of uterine leiomyosarcoma may vary from person to person. They can include:

  • abnormal bleeding from the vagina and uterus
  • postmenopausal bleeding
  • pain or pressure in the pelvis or stomach
  • change in bladder or bowel habits
  • abnormal vaginal discharge
  • unexplained weight loss
  • fever
  • fatigue
  • generally feeling unwell

However, experts note that symptoms can be similar to other disorders, such as endometrial carcinoma and uterine fibroids. Fibroids may present with bleeding and pain eventually, but initially may not have any symptoms.

The exact cause of uterine leiomyosarcoma is unclear. The condition can occur for no identifiable reason.

Some researchers believe that, in rare cases, a benign fibroid may develop into uterine leiomyosarcoma, but more research into this is necessary.

The following may be factors that increase the risk of uterine leiomyosarcoma:

  • abnormal genetic changes
  • inherited conditions such as Gardner syndrome and Li-Fraumeni syndrome
  • exposure to high-dose radiation or certain chemicals
  • exposure to ultraviolet rays
  • diet
  • stress

Other studies suggest the following as risk factors:

  • obesity
  • using estrogen and progestin in menopause
  • oral contraceptives
  • never having been pregnant
  • using tamoxifen

Doctors commonly discover uterine leiomyosarcoma when operating on individuals for benign tumors such as fibroids. They can diagnose the condition by analyzing the tissue in a laboratory.

A doctor may also use imaging techniques such as CT scans or X-rays to evaluate a tumor. They may perform a diagnostic procedure known as fine-needle aspiration. This involves using a thin, hollow needle to withdraw tissue samples.

The doctor may also carry out a biopsy by removing a tissue sample through an incision.

Learn more about tests for uterine cancer.

The treatments for uterine leiomyosarcoma depend on the stage of the cancer and whether it has spread.

The American Cancer Society (ACS) notes that most people with uterine leiomyosarcoma have a hysterectomy. This is a surgical procedure to remove the uterus.

Doctors may leave the ovaries intact in individuals who still have regular menstrual cycles. During the surgery, doctors examine tissue and organs near the uterus to see if the cancer has spread. They may remove additional tissue if this is the case.

Some people require chemotherapy or radiation therapy following surgery to kill any remaining cancer cells. Follow-up appointments can also help a doctor closely watch to see if the cancer returns.

If the cancer has spread to the lungs, liver, or bones, there is no standard treatment available except for chemotherapy or radiotherapy, which may shrink the tumors for a time.

Targeted therapy may also be an option in some cases. This can include the oral multikinase inhibitor pazopanib. A 2022 study found that people who received pazopanib had progression-free survival for 4.6 months, compared with 1.6 months for those who received a placebo.

Learn more about treatments for uterine cancer.

The following answers some frequently asked questions.

What is the survival rate for uterine leiomyosarcoma?

According to the ACS, the 5-year relative survival rate for people who received a uterine leiomyosarcoma diagnosis between 2012 and 2018 was as follows:

  • Localized: 60%
  • Regional: 37%
  • Distant: 12%
  • All SEER stages combined: 38%

However, it is important to note that the outlook will differ for each individual. A person’s doctor can provide more accurate information on the basis of their individual circumstances.

A relative survival rate helps give an idea of how long a person with a particular condition will live after receiving a diagnosis compared with those without the condition.

For example, if the 5-year relative survival rate is 70%, it means that a person with the condition is 70% as likely to live for 5 years as someone without the condition.

It is important to remember that these figures are estimates. A person can consult a healthcare professional about how their condition is going to affect them.

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Is leiomyosarcoma of the uterus curable?

Studies suggest that uterine leiomyosarcoma is an aggressive condition that has a poor outlook because it is resistant to standard therapy and has a high risk of recurring. However, the possibility of curing the condition depends on the individual case.

How common is leiomyosarcoma of the uterus?

Uterine leiomyosarcoma is a rare condition that occurs in 6 in every 1 million females in the United States each year. The average age at the time of diagnosis is 51 years.

The condition accounts for around 1–2% of all malignant tumors of the uterus and around 30% of all uterine sarcomas.

Uterine leiomyosarcoma is a rare and aggressive cancer that grows in the smooth muscle of the uterus. It can cause symptoms such as abnormal bleeding and vaginal discharge.

Scientists do not know exactly what causes it, but they have identified numerous possible risk factors.

Doctors commonly discover uterine leiomyosarcoma when operating on a person for benign conditions such as fibroids. They usually treat the cancer with a hysterectomy, and they may follow this up with chemotherapy or radiation therapy.